bath/asme symposium on fluid power and motion control · 16:45 8917 andrea de martin, andrea...

Bath/ASME Symposium on

Fluid Power and Motion Control

FPMC 2018

12 - 14 September 2018 Contents Technical Programme 5 Social Programme 9 Obituary 10 The Robert E. Koski Medal 11 The Joseph Bramah Medal 12 Best Paper Award 13 FPMC 2018 Organisers 14 Abstracts 15 Maps 37

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Bath/ASME Symposium on Fluid Power and Motion Control FPMC 2018, 12 - 14 September 2018

University of Bath

FPMC 2018

12-14 September 2018

Lecture Room CB 2.6, Chancellors’ Building, University of Bath (also parallel sessions in room CB 1.12, Thursday only)

Delegates can register and pick up Symposium files in Chancellors’ Building Foyer

on Wednesday 12th September, 08:15-08:45 To aid in the smooth running of the Symposium, Presenting Authors and Chairs are asked to meet in the lecture room 15 minutes before the start of their session so that their presentations can be set up. If possible, presentations should be brought on a flash drive and copied onto the lecture room PC.


University of Bath

Programme for Wednesday 12th September

Chancellors’ Building Room CB 2.6

08:45 – 09:00 Introduction

09:00 – 10:30 Session 1: Efficient and Intelligent Systems Chair: Travis Wiens 09:00 8812 Heikki Kauranne, Teemu Koitto, Olof Calonius, Tatiana Minav and Matti Pietola, Direct Driven Pump Control of Hydraulic

Cylinder for Rapid Vertical Position Control of Heavy Loads – Energy Efficiency Including Effects of Damping and Load Compensation

09:15 8840 Litong Lyu, Zheng Chen and Bin Yao, High Precision Energy Saving Motion Control of Hydraulic Cylinder Based on Integration of Valves and Pump

09:30 8871 Damiano Padovani and Eric Barth, Exploiting Valve Timing for Pneumatic Energy Savings

09:45 8919 Seppo Tikkanen, Ville Ahola and Elias Koskela, Effect of Driver and Work Cycle on Losses of a Loader

10:00 8936 Bernhard Manhartsgruber, A Novel Concept for Boosting the Suction Line of Piston Pumps by Piezo-Actuated Pipe Walls

10:15 Discussion

10:30 – 11:00 Break

11:00 – 12:30 Session 2: Modelling and Simulation Chair: Kazushi Sanada 11:00 8813 Rahelehsadat Mostafavi, Dominic Tiffin and Katharina Schmitz, Determination of the Dynamic Characteristics of a

Hydraulic Reservoir for its Air Release Efficiency Using Multiphase CFD Model

11:15 8859 Sven Osterland and Jürgen Weber, Analytical Description of the Static and Dynamic Behaviour of a Pressure Relief Valve

11:30 8881 Travis Wiens and Jeremy ven der Buhs, An Improved Transmission Line Model for Dynamic Laminar Flow Through Tapered Tubes

11:45 8913 Barbara Zardin, Giovanni Cillo, Massimo Borghi, Peter Zavadinka and Juraj Hanusovsky, Modelling and Simulation of a Cartridge Pressure Amplifier

12:00 8925 Pietro Marani, Cristian Ferrari and Massimo Milani, CFD Analysis of Compensator for Meter Out Sensing System

12:15 Discussion

12:30 – 14:00 Lunch

14:00 – 15:15 Session 3: Digital and Switched Fluid Power Systems Chair: Perry Li 14:00 8810 Giacomo Kolks and Jürgen Weber, Symmetric Single Rod Cylinders with Variable Piston Area? A Comprehensive

Approach to the Right Solution

14:15 8829 Chenggang Yuan, Min Pan and Andrew Plummer, A Review of Switched Inertance Hydraulic Converter Technology

14:30 8858 Henrik B. Larsen, Magnus Kjelland, Per N. Lindholdt and Anders Holland, Digital Hydraulic Winch Drives

14:45 8866 Matti Linjama, Model-Based Control of a Digital Hydraulic Transformer-Based Hybrid Actuator

15:00 Discussion

15:15 – 15:45 Break

15:45 – 17:15 Session 4: Applications of Fluid Power Chair: Noah Manring 15:45 8862 Magnus Landberg, Robert Braun, Magnus Sethson and Petter Krus, The Hydraulic Infinite Linear Actuator Applied to

Elevators in Mid-Rise Buildings

16:00 8889 Lasse Schmidt, Henrik Pedersen, Viktor Donkov and Torben Andersen, Analysis & Control of a Self-contained Hydraulic Winch Drive

16:15 8890 Lauri Siivonen, Jyrki Tammisto, Kalevi Huhtala and Olli Tiainen, Hydraulic-Mechanic Damper Concept for Thruster Ice Impact Load Reduction

16:30 8895 Jean-Charles Mare and Silvio Akitani, Foundation for Virtual Prototyping of Mechanical Power Management Functions in Actuators

16:45 8917 Andrea De Martin, Andrea Dellacasa, Giovanni Jacazio and Massimo Sorli, High-Fidelity Model of Hydraulic Actuators for Primary Flight Control Systems

17:00 Discussion

17:15 Close

Evening: Reception, Holburne Museum, Bath. See page 9 for details.


University of Bath

Programme for Thursday 13th September

Parallel Session A, Room CB 1.12: Systems and Control 09:00 – 10:30 Session 5: Motion Control 1 Chair: Steve Weber 09:00 8835 Huan Yu, JianHua Wei, JinHui Fang, Ge Sun and Hangjun Zhang, Predictive Robust Control based on Higher-Order Sliding

Mode for Passive Heave Compensator with Hydraulic Transformer 09:15 8841 Pauli Mustalahti and Jouni Mattila, Nonlinear Model-Based Controller Design for a Hydraulic Rack and Pinion Gear

Actuator 09:30 8847 Jarmo Nurmi, Mohammad M. Aref and Jouni Mattila, A Neural Network Strategy for Learning of Nonlinearities Toward

Feed-Forward Control of Pressure-Compensated Hydraulic Valves with a Significant Dead Zone 09:45 8863 Hongzhao Zhou, Andrew Plummer and David Cleaver, Closed Loop Position and Pre-stress Control for a Morphing

Aircraft Wing with Distributed Multi-axis Pneumatic Actuation 10:00 8870 Niels Christian Bender, Henrik Pedersen, Torben Andersen and Michael Bech, A Multi-agent Evolution Algorithm for

Input shaping of a Repetitive Non-linear Dynamic System 10:15 Discussion

10:30 – 11:00 Break

11:00 – 12:30 Session 6: Motion Control 2 Chair: James Van de Ven 11:00 8868 Nils Trochelmann, Phillip Bischof-Stump, Frank Thielecke, Dirk Metzler and Stefan Bassett, A Robust Pressure Controller

for a Variable Speed AC Motor Pump - Application to Aircraft Hydraulic Power Packages 11:15 8877 L. Viktor Larsson and Petter Krus, A General Approach to Low-Level Control of Heavy Complex Hybrid Hydromechanical

Transmissions 11:30 8896 Siavash Danaee, Jarmo Nurmi, Tatiana Minav, Jouni Mattila and Matti Pietola, Direct Position Control of Electro-

Hydraulic Excavator 11:45 8935 Sangyoon Lee and Perry Li, Supervisory Control for a Switched Mode Hydraulic Transformer 12:00 8938 Addison Alexander, Annalisa Sciancalepore and Andrea Vacca, Online Controller Setpoint Optimization for Traction

Control Systems Applied to Construction Machinery 12:15 Discussion

12:30 – 14:00 Lunch

14:00 – 15:30 Session 7: System Design, Fault Analysis and Diagnosis Chair: Hubertus Murrenhoff 14:00 8802 Karl Uebel, Henrique Raduenz, Petter Krus and Victor De Negri, Design Optimisation Strategies for a Hydraulic Hybrid

Wheel Loader 14:15 8805 Junxia Guo, Jianfeng Tao, Lin Li and Chengliang Liu, Diagnosis Method for Valve-controlled Hydraulic Cylinder Leakage

Based on Subspace Identification 14:30 8808 Paolo Casoli, Andrea Bedotti, Mirko Pastori and Antonio Lettini, Condition Monitoring Based on Thermodynamic

Efficiency Method for an Axial Piston Pump 14:45 8833 Raphael Alt, Justus Malzahn, Hubertus Murrenhoff and Katharina Schmitz, A Survey of Industrial Internet of Things in

the Field of Fluid Power - Basic Requirements for Plug-and-Play 15:00 8864 Paolo Tamburrano, Riccardo Amirante, Elia Distaso and Andrew Plummer, A Novel Piezoelectric Double-Flapper

Servovalve Pilot Stage: Operating Principle and Performance Prediction 15:15 Discussion

15:30 – 16:00 Break

16:00 – 17:30 Session 8: Rheology, Tribology and Cavitation Chair: Andrea Vacca 16:00 8807 Philipp Weishaar, Alexander Görres, Hubertus Murrenhoff and Katharina Schmitz, Investigating Electrostatic Flow

Charging using a Small Scale Test Bench 16:15 8815 Felix L. Fischer, Julian Bartz, Katharina Schmitz, Ludwig Brouwer and Hubert Schwarze, A Numerical Approach for the

Evaluation of a Capillary Viscometer Experiment 16:30 8872 Filipp Kratschun, Tobias Mielke and Katharina Schmitz, Water Vapour Cavitation in Hydraulic Fluids 16:45 8904 Haihang Wang, He Xu, Zitiong Zhao, Vishwanath Pooneeth and Liye Jiao, Development of Visualized Water Hydraulic

Experiment System for Studying the Bubble Flow Pattern Inside Valve 17:00 8933 Jannik Hartwig Jakobsen and Michael Rygaard Hansen, Synthetic Esters and Dynamics of Pressure Compensated

Proportional Directional Control Valves 17:15 Discussion

17:30 Close

Evening: Symposium Dinner and Awards Presentation. See page 9 for details.


University of Bath

Programme for Thursday 13th September

Parallel Session B, Room CB 2.6: Pumps and Motors 09:00 – 10:15 Session 9: Piston Pumps and Motors Chair: Bernhard Manhartsgruber 09:00 8822 Yapeng Xu, Kai Guo, Jianfeng Li and Keyu Wang, The Torque on the Swashplate of Axial Piston Variable Displacement

Pumps with Conical Cylinder Blocks

09:15 8825 Nathaniel J. Fulbright and James D. Van de Ven, Dynamic Response of Pressure Compensated Variable Displacement Linkage Pump

09:30 8832 Peter A J Achten, Jeroen Potma and Jasper Achten, Low Speed Performance of Axial Piston Machines

09:45 8937 Liselott Ericsson and Jonas Forssell, A Novel Axial Piston Pump/Motor Principle with Floating Pistons - Design and Testing

10:00 Discussion

10:15 – 11:00 Break

11:00 – 12:30 Session 10: Vane and Gear Pumps and Motors Chair: Peter Achten 11:00 8857 Ryan Jenkins and Monika Ivantysynova, An Empirically Derived Pressure Compensation Control System for a Variable

Displacement Vane Pump

11:15 8876 Andrew Robison and Andrea Vacca, Multi-Objective Geometric Optimization of Elliptical-toothed Gerotor Pumps for Kinematics and Wear by Genetic Algorithm

11:30 8902 Divya Thiagarajan and Andrea Vacca, Modeling of the Lateral Lubricating Interfaces in External Gear Machines Considering the Effects of Cavitation

11:45 8903 Xinran Zhao, Andrea Vacca and Sujan Dhar, Numerical Modeling of a Helical External Gear Pump with Continuous-Contact Gear Profile: A Comparison between a Lumped-Parameter and a 3D CFD Approach of Simulation

12:00 8928 Christian Schänzle, Nils Störmer and Peter F. Pelz, Modeling The Efficiency of Gear Pumps Based on Similarity Considerations

12:15 Discussion

12:30 – 14:00 Lunch (Lime Tree Restaurant)

14:00 – 15:30 Session 11: Noise and Vibration Chair: Kalevi Huhtala 14:00 8809 Ryan Foss, Mengtang Li, Eric Barth, Kim Stelson and James D. Van de Ven, Addressing Valves with Pressure Ripple

14:15 8855 Wieslaw Fiebig and Jakub Wrobel, System Approach in Vibration and Noise Investigation in Fluid Power Units

14:30 8828 Min Pan, Beichen Ding, Chenggang Yuan, Jun Zou and Huayong Yang, Novel Integrated Control of Fluid-borne Noise in Hydraulic Systems

14:45 8899 Paul Kalbfleisch, Svenja Horn and Monika Ivantysynova, Cyclostationary Analysis of Measured Pump Acoustic and Vibration Signals

15:00 8856 Wieslaw Fiebig, Jakub Wrobel and Piotr Cependa, Transmission of Fluid Borne Noise inside the Reservoir

15:15 Discussion

15:30 – 16:00 Break

16:00 – 17:30 Session 12: Digital Displacement Pumps and Motors Chair: Matti Linjama 16:00 8834 Noah Manring and Chris Williamson, Calculating the Mechanical and Volumetric Efficiencies for Check-Valve Type,

Digital-Displacement Pumps

16:15 8874 Niels Henrik Pedersen, Per Johansen and Torben Andersen, Four Quadrant Hybrid Control Oriented Dynamical System Model of Digital Displacement Units

16:30 8894 Matt Green, Jill Macpherson, Niall Caldwell and Win Rampen, DEXTER - The Application of a Digital Displacement Pump to a 16 Tonne Excavator

16:45 8908 Sondre Nordås, Morten Kjeld Ebbesen and Torben Andersen, Analysis of Requirements for Valve Accuracy and Repeatability in High Efficiency Digital Displacement Motors

17:00 8922 Niall Caldwell, Review of early work on Digital Displacement® Hydrostatic Transmission Systems

17:15 Discussion

17:30 Close

Evening: Symposium Dinner and Awards Presentation. See page 9 for details.


University of Bath

Programme for Friday 14th September

Chancellors’ Building Room 2.6

09:00 – 10:30 Session 13: Renewable Energy and Hybrid Vehicles Chair: Kim Stelson 09:00 8853 Mikko Heikkilä, Mikko Huova, Jyrki Tammisto, Matti Linjama and Jussi Tervonen, Fuel Efficiency Optimization of a

Baseline Wheel Loader and Its Hydraulic Hybrid Variants Using Dynamic Programming

09:15 8869 Mikko Huova, Jyrki Tammisto, Matti Linjama and Jussi Tervonen, Fuel Efficiency Analysis of Selected Hydraulic Hybrids in a Wheel Loader Application

09:30 8912 Qunya Wen, Feng Wang and Bing Xu, Modeling and design of a series hydraulic hybrid powertrain for compact wheel loaders

09:45 8900 Biswaranjan Mohanty and Kim Stelson, High Fidelity Dynamic Modeling and Control of Power Regenerative Hydrostatic Wind Turbine Test Platform

10:00 8921 Haoxiang Zhang, Feng Wang and Bing Xu, Modeling and Experimental Study of a Novel Power Split Hydraulic Transmission

10:15 Discussion

10:30 – 11:00 Break

11:00 – 12:30 Session 14: Robotics and Prosthetics Chair: Jan-Ove Palmberg 11:00 8839 Janne Koivumaki, Wen-Hong Zhu and Jouni Mattila, Addressing Closed-Chain Dynamics for High-Precision Control of

Hydraulic Cylinder Actuated Manipulators

11:15 8842 Santeri Lampinen, Janne Koivumaki and Jouni Matilla, Bilateral Teleoperation of a Hydraulic Robotic Manipulator In Contact With Physical and Virtual Constraints

11:30 8846 Petri Mäkinen, Oleg Dmitrochenko and Jouni Mattila, Floating Frame of Reference Formulation for a Flexible Manipulator with Hydraulic Actuation - Modelling and Experimental Validation

11:45 8875 Rudolf Scheidl and Simon Mittlböck, A Hydraulic Piloting Concept of a Digital Cylinder Drive for Exoskeletons

12:00 8891 Mikko Huova, Matti Linjama, Lauri Siivonen, Till Deubel, Heino Försterling and Edgar Stamm, Novel Fine Positioning Method for Hydraulic Drives Utilizing On/Off-Valves

12:15 Discussion

12:30 – 12:40 Closure

12:40 – 14:00 Lunch


University of Bath

Social Programme

Wednesday Evening: Reception and Hot Bowl Food at Holburne Museum, Bath

18:15 Coach departs from middle of East Car Park, University of Bath Claverton Down Campus (see map on page 37).

18:30 – 20:00 Reception and hot bowl food.

You are free to explore Bath afterwards. There is a regular bus service back to the University if required – please ask one of the organisers for details.

Thursday Evening: Symposium Dinner and Awards Presentation

18:40 Coach departs from middle of East Car Park, University of Bath Claverton Down Campus (see map on page 37).

19:00 Reception drinks at the Assembly Rooms

19:30 Dinner, followed by presentations

22:30 Coach departs from Assembly Rooms to return to the University.

The 2018 Robert E. Koski Medal, 2016 and 2017 IMechE Joseph Bramah medals, and the FPMC 2017 Best Paper award will be presented at the dinner.

The Holburne Museum and Great Pulteney Street, viewed from Laura Place

Obituary: Monika Ivantysynova

We are shocked and saddened by the news that one of our most esteemed colleagues, Monika Ivantysynova, passed away on the 11th of August, following a 4 month battle with cancer. Monika was extremely active in the international fluid power research community, not least through her contributions to this Symposium over many years, and was a highly valued member of the ASME Fluid Power Systems and Technology Division. Her passion for the subject inspired researchers and engineers all over the world.

Monika Ivantysynova was born in 1955 in Polenz, Germany. After completing her PhD at the Technical University of Bratislava in 1983, she worked for seven years in industry, gaining expertise in hydraulic systems and component design, modeling and system simulation, and in the development of hydraulic pumps and motors. In 1990 she returned to academia, where she researched hydraulic actuation systems and control for aircraft applications at the Technical University of Hamburg-Harburg. In 1996 she took up the Chair in Hydraulic Systems and Control at the University of Duisburg, returning to TUHH as Professor of Mechatronic System Design three years later, establishing a comprehensive fluid power research laboratory. In 2004 Monika was appointed MAHA Professor of Fluid Power Systems at Purdue University, where she pushed ahead with her many research passions, including comprehensive simulation and optimization methods for hydraulic piston pumps, and energy-efficient mobile hydraulic machines using pump-controlled actuation.

As well as being a dedicated leader of her own research team, she energetically engaged with fluid power researchers throughout the world, travelling to the major conferences on all continents. Her presence – questioning, cajoling, encouraging – always enlivened proceedings and forced us all to think deeply about the subject. As well as her seminal book “Hydrostatic Pumps and Motors” published in German and English, and her very many research papers, she founded and was editor-in-chief of the International Journal of Fluid Power published by Taylor & Francis – the only international journal dedicated to fluid power. She was a pivotal figure in the multi-university Centre for Compact and Efficient Fluid Power, creating a renaissance in fluid power research and education in the USA. She was also a driving force behind the Fluid Power Net International, and a founding Director of the Global Fluid Power Society.

Her accolades were many. She received both pre-eminent international awards for fluid power: the 2009 Joseph Bramah Medal from the United Kingdom’s Institution of Mechanical Engineers, and the 2015 Robert E. Koski medal from the American Society of American Engineers. She was awarded two honorary doctorates, and too many Best Paper prizes to list.

The fluid power community will not be the same without Monika - an inspirational individual who was passionate about the subject. We are lucky to have known her, and will miss her greatly. Andrew Plummer Director, Centre for Power Transmission and Motion Control, University of Bath Chair, Global Fluid Power Society

The Robert E. Koski Medal The Robert E. Koski Medal, established in 2007, recognizes individuals who have advanced the art and practice of fluid power motion and control through education and/or innovation. The Medal was established by the Fluid Power Systems and Technology Division to honour Robert E. Koski's contributions to the field of Design Engineering and Dynamic and Systems and Control.

The 2018 Robert E. Koski Medal will be awarded to Dr Luca Zarotti of Universita' degli Studi di Ferrara, Italy.

Previous Recipients

2017 Werner Dieter 2016 Kim Stelson 2015 Monika Ivantysynova 2014 Hubertus Murrenhoff 2013 Wayne J. Book 2012 Siegfried Helduser 2011 Richard T. Burton 2010 Yongxiang Lu 2009 Jan Ove Palmberg 2008 Clifford R. Burrows 2007 Wolfgang Backe

Dr Ferdi Megerlin receives the Koski medal on behalf of Dr Werner Dieter at FPMC 2017

in Sarasota

Dr Luca Zarotti

The Joseph Bramah Medal The Joseph Bramah Fund was established in 1968 at the instigation of Mr Frank Towler, a Fellow of the Institution of Mechanical Engineers (1932-1977), who arranged for its support by industry to commemorate Joseph Bramah, the inventor of a patent lock, the hydraulic press and other inventions concerned with pumps, water supply and the production of pipes and tubes by the extrusion process. The 2016 Joseph Bramah Medal will be awarded to Professor Andrew Plummer, Director of the Centre for Power Transmission and Motion Control, University of Bath. The 2017 Joseph Bramah Medal will be awarded to Professor Huayong Yang, Head of School of Mechanical Engineering, and the Director of the State Key Laboratory of Fluid Power and Mechatronic Systems, Zhejiang University, China.

Previous Recipients 2015 John Savage, National Fluid Power Centre 2014 Professor Win Rampen, Edinburgh University and Artemis Intelligent

Power 2013 Professor Richard Burton, University of Saskatchewan 2011 Professor Shinichi Yokota, Tokyo Institute of Technology 2010 Professor Rudolf Scheidl, Johannes Kepler University 2009 Professor Monika Ivantysynova, Purdue University 2008 Professor Siegfried Helduser, Technical University of Dresden 2007 Dr Peter Achten, Innas BV 2006 Professor Serge Scavarda, INSA Lyon 2005 Professor Matti J. Vilenius, Tampere University 2004 Professor Hans-Heinrich Harms, Technical University, Braunschweig,

Germany 2003 Mr Roy Cuthbert 2002 Mr John Bentley 2001 Professor Hubertus Murrenhoff 1999 Professor J Watton 1998 M D Kelley 1997 Professor Jan-Ove Palmberg 1996 Mr Norman Way 1995 Dr W Dieter 1994 P J Wilson 1993 Professor C Burrows 1992 Robert Koski 1991 Professor Dr Ing Wolfgang Backe 1990 Dr Kevin Edge 1989 G Allison 1988 R B Walters 1987 R E Knight 1986 F B Levetus 1985 J F Nosworthy 1984 G C Knight 1982 M J Fisher 1981 F W Baggett 1974 C M Edgehill 1980 D Bick 1973 Professor W M J Schlosser 1979 E H Bowers 1972 R H Y Hancock 1978 Professor D E Bowns 1971 K Foster 1976 P M M Price 1970 G P Copping 1975 J G Keenan 1968 B Lengyel

Professor Huayong Yang

Professor Andrew Plummer

FPMC Best Paper Award The FPMC Best Paper award is awarded based on scoring by the Symposium delegates, on the basis of technical quality and presentation quality. The award is presented in the following year’s Symposium. The FPMC 2017 Best Paper Award will be awarded to Divya Thiagarajan, Andrea Bratto and Andrea Vacca, of Purdue University, for their paper entitled Influence of Surface Roughness Effects on the Lubrication Performance of External Gear Machines.

Previous Recipients, 2008-2016 2016 Tian Yu, Andrew Plummer, Pejman Iravani, Jawaad Bhatti, Saeed Zahedi and David Moser, The

Design, Analysis and Testing of a Compact Electrohydrostatic Powered Ankle Prosthesis 2015 Stefan Heitzig, Gregor Bultel and Hubertus Murrenhoff, Efficiency Improvement of Common-Rail

Pumps by Gap Compensation based on Hollow Pistons. 2014 Johannes Willkomm, Matthias Wahler and Juergen Weber, Process-Adapted Control to Maximize

Dynamics of Speed- and Displacement-Variable Pumps 2013 Johannes Schmitz, Milos Vukovic and Hubertus Murrenhoff, Hydrostatic Transmission for Wind

Turbines – an Old Concept, New Dynamics 2012 Henrik C Pedersen, Anders H Hansen, Rico H Hansen, Torben O Andersen and Michael M Bech, Design and Control of Full Scale Wave Energy Simulator System 2011 Matteo Pelosi and Monika Ivantysynova, A Novel Thermal Model for the Piston/Cylinder Interface of

Piston Machines 2010 Rico Hansen, Torben Andersen and Henrik Pedersen, Development and implementation of an

advanced power management algorithm for electronic load sensing on a telehandler 2009 Joshua Zimmerman and Monika Ivantysynova, Effect of Installed Hydraulic Corner Power on the

Energy Consumption and Performance of Multi-Actuator Displacement Controlled Mobile Machines 2008 José Riofrío and Eric Barth, Experimental assessment of a free elastic-piston engine compressor with

separated combustion chamber

FPMC 2018 Organisers Organising Committee:

Nigel Johnston, University of Bath Andrew Plummer, University of Bath Steve Weber, Sun Hydraulics

Technical Program Chair:

Nigel Johnston, University of Bath Administrator:

Gillian Elsworth, University of Bath Associate Editors /Session Organisers:

Eric Barth, Vanderbilt University Roger Fales, University of Missouri Kalevi Huhtala, Tampere University Songjing Li, Harbin Institute of Technology Bernhard Manhartsgruber, Johannes Kepler University, Linz Noah Manring, University of Missouri Hubertus Murrenhoff, RWTH Aachen University Victor de Negri, Federal University of Santa Catarina Kazushi Sanada, Yokohama National University Rudolf Scheidl, Johannes Kepler University, Linz Kim Stelson, University of Minnesota Andrea Vacca, Purdue University James Van de Ven, University of Minnesota Jürgen Weber, Technische Universität Dresden Steve Weber, Sun Hydraulics Travis Wiens, University of Saskatoon


University of Bath

Abstracts

Session 1: Efficient and Intelligent Systems

Wednesday 12th September 09:00 – 10:30

09:00 8812 Heikki Kauranne, Teemu Koitto, Olof Calonius, Tatiana Minav and Matti Pietola, Direct Driven Pump Control of Hydraulic Cylinder for Rapid Vertical Position Control of Heavy Loads – Energy Efficiency Including Effects of Damping and Load Compensation

The ever-tightening government-enforced regulations for more energy efficient and less polluting machines and the simultaneous fast development of electric drives have caused hydraulic systems to lose ground to electric drives. One promising solution to improve the status of hydraulics in this competition are the Direct Driven Hydraulic (DDH) systems, aka electro-hydraulic actuators (EHAs), which are characterized by a closed circuit type and a servo motor driven speed-controlled pump controlling the actuator. Due to this topology, they offer a possibility of reaching higher energy efficiencies compared to traditional open circuit type valve controlled systems and simultaneously they offer the high accuracy and dynamics of these. Typical applications where DDHs have been used are, in the area of mobile equipment, modern commercial and military aircrafts and some lift trucks, and in the area of stationary applications, mostly presses. In all of these, the actuators produce relatively slow motions. In this experimental study, a DDH system is applied to a stationary industrial vertical position control application where a very rapid movement of a heavy load is required. This brings out some unwanted fluctuation phenomena not encountered with slower motion velocities. Here we are striving for avoiding these phenomena by adding damping to the system. In addition, it is studied whether the good energy efficiency of DDH systems could be enhanced with load-compensation.

The presented measurement results include the system behavior regarding the smoothness of positioning, the fluctuations of pressures, forces, and power, and finally the energy consumption with three different system configurations: basic DDH, load-compensated DDH, and load-compensated and damped DDH. The measured energy consumptions are compared against results gained in simulating a conventional valve-controlled system driving the same application. The measurement results manifest that energy consumption wise significant benefits are achievable with DDH, especially in combination with hydraulic load compensation. However, without added damping the motion involved marked vibrations in the end of the upward and downward strokes. Added damping eliminated these vibrations, but at the cost of reduced energy efficiency. Due to this, the solution for the fluctuation and vibration problem should be sought by developing a control strategy that produces a smoother but as fast motion.

Keywords: Components and systems, Drives, transmissions and actuators, Fluid Power Systems

09:15 8840 Litong Lyu, Zheng Chen and Bin Yao, High precision energy saving motion control of hydraulic cylinder based on integration of valves and pump

The independent metering approach makes the two chamber pressure states of the hydraulic actuator completely controllable, which offers the opportunity for energy conservation by reducing the working pressure. However, there still remains a great deal of throttling losses since the entire flow rate is throttling controlled with the valves. In order to avoid throttling losses, the direct pump controlled system might be an option, but the relatively slow dynamic response restricts its application in occasions with response and precision demands. To realize further energy conservation and simultaneous high precision tracking performance, this paper proposes a brand new hardware configuration which integrates the direct pump control, independent metering, and energy reuse methods and takes advantages of their respective strengths. The adaptive robust control approach is applied to deal with the nonlinear control problems. Comparative simulations are done with the focuses on energy consumption and tracking performance.

Keywords: Control, Efficient and intelligent systems, System design

09:30 8871 Damiano Padovani and Eric Barth, Exploiting Valve Timing for Pneumatic Energy Savings

This research paper aims at addressing solutions that reduce air consumption in generic pneumatic systems used for pick-and-place operations. The investigation considers different system architectures both with a single control valve and two control valves arranged according to an independent metering configuration. Suitable control strategies are then proposed exploiting multiple timings to shut off the non-proportional switching valve(s). The resulting scenarios are experimentally evaluated on a dedicated test-bed. The main conclusion is that reduction of air consumption up to 73% is possible in comparison to the state-of-the-art layout for the reference application. Numerical simulations obtained by means of specific dynamic models suggest these air savings are consistent for actuators with different strokes.

Keywords: Components and systems, Digital and switched fluid power systems, Efficient and intelligent systems, Modelling and Simulation, System design

09:45 8919 Seppo Tikkanen, Ville Ahola and Elias Koskela, Effect of driver and work cycle on losses of a loader

Improving the energy efficiency of mobile machines requires information about the initial state of the machine. This information includes knowledge of the systems and their components and of course, measurement data that is acquired during typical operation. Machine manufacturers and research institutes have carried out extensive measurement programs during the last decade. Usually, the published studies concentrated on one work cycle, the machines studied were operated by humans, and it is shown that productivity and fuel consumption are dependent on the machine design, work cycle and operator. This study concentrates on a detailed analysis of the energy consumption of a municipal loader during measured work tasks. The goal was to find out how much the driver and work cycle affect the machine’s energy consumption and energy distribution. To evaluate the real fuel consumption and energy distribution, the measurements consisted of two different work cycles that were driven by two drivers with different skill levels. The first cycle was the classic short wheel loader loading cycle, the Y-cycle. In this task, the loader was equipped with a bucket, and a pile of gravel was moved from pile A to pile B in a Y-pattern. The second cycle was the load and carry cycle in which the driver picked up a load with the forklift attachment and carried the load over a predefined distance. The major finding was that the impact of the driver and the work cycle is considerable in fuel consumption. The difference is also seen in the energy distribution in the hydraulic system and in losses and how the losses are divided. Therefore, it can be stated that test results with one driver or one cycle should not be generalized without concern and judgement of novel concepts requires several tests with different drivers and work cycles.

Keywords: Drives, transmissions and actuators, Fluid Power Systems

10:00 8936 Bernhard Manhartsgruber, A Novel Concept for Boosting the Suction Line of Piston Pumps by Piezo-Actuated Pipe Walls

Axial and radial piston pumps are the work horse of the fluid power industry in the medium to high power range. During the maturation of the technology in the last five decades, both the pressure levels and the maximum rotational speeds have been increased significantly to meet the market demands for an increased power to weight or size ratio. The maximum speed of operation is often limited by cavitation occuring in the suction duct of pumps. A well known but expensive solution to the problem is the use of booster pumps to raise the suction pressure at the piston pump inlet. The rationale behind this solution is vary simple: The pressure oscillations inevitably caused by the nonuniform operation of the piston pump will occur around an increased mean pressure level, thereby raising also the pressure minima and avoiding cavitation. The present paper looks into the dynamics of the suction process in more detail. A simulation model of an axial piston pump with a detailed model of the wave propagation in the suction line is analysed for the potential of mitigating the pressure oscillations locally at the pump inlet by actuating the pipe wall for instance with piezo ring actuators. In a first simulation study, the power electronics of the actuation system is idealized and a mathematical optimization of the actuations signals for a certain operating point of the pump is set up. A theoretical proof of concept can be achieved in this simulation. An experimental proof of concept is left to future work at this point.

Keywords: Components and systems, Efficient and intelligent systems, Modelling and Simulation

Session 2: Modelling and Simulation


11:00 8813 Rahelehsadat Mostafavi, Dominic Tiffin and Katharina Schmitz, Determination of the Dynamic Characteristics of a Hydraulic Reservoir for its Air Release Efficiency Using Multiphase CFD Model

Undissolved air in oil causes various problems for hydraulic systems and strongly decreases the efficiency of the system. In this respect, the hydraulic reservoir as the only component that performs the function of releasing the accumulated air from the system is relevant. In recent years, the air release efficiency in hydraulic reservoirs has been studied both experimentally and in simulation. However, in none of the according studies dynamically changing flow conditions have been considered. In this paper, the air release behaviour of a hydraulic reservoir is investigated through simulation, considering the dynamics of the system. The developed multiphase CFD model utilizes the open-source CFD tool, OpenFOAM®, based on a Lagrangian particle tracking (LPT) within an Eulerian phase. The simulations have been conducted varying the key variables such as oil flow rate and air load at the inlet of the reservoir and yield the air content at the outlet.

Keywords: Components and systems, Control, Fluid Power Systems, Modelling and Simulation,

11:15 8859 Sven Osterland and Jürgen Weber, Analytical description of the static and dynamic behaviour of a pressure relief valve

The paper presents an explicitly straightforward formulation of the stationary and dynamic behaviour of a pressure relief valve (PRV). This makes it possible to consider the static, dynamic and robustness properties of a PRV during the analysis or design process. A PRV can be understood as a self-regulating, cross-domain system. The governing equations are well known and widely used in literature. Usually, these include: a geometrical description of the flow area and the pressure surface, a flow equation, the pressure build-up equations, a spring-like counterforce, a flow force, a term for viscous friction and the inertia force. Together they form a system of ordinary non-linear differential equations of third order. So far, these equations had to be solved numerically in order to analyse or adapt the static or dynamic properties of a particular PRV. In this paper, direct analytical solutions for stationary and dynamic cases are derived. This results in an explicit equation for the respective p-Q characteristic curve. In addition, a simple criterion for the stability of a PRV was found. As it turns out, the minimum requirement for viscous damping is directly anti-proportional to the gradient of the p-Q characteristic curve. It is empirically known that decreasing the gradient of the p-Q curve makes the system more susceptible to oscillations. However, this has not yet been shown mathematically elegant. The method presented here calculates the static p-Q curve, the stability and natural frequencies of a PRV in a simple procedure using only elementary mathematics - no numerical scheme is required. Thus, the new method offers four main advantages. First, it is several orders of magnitude faster because it is not necessary to solve the differential equation system numerically. Secondly, the user does not require any special knowledge or advanced calculation tools - a simple spreadsheet program is sufficient. This eliminates licensing and training costs. Third, sensitivity and robustness analyses can be carried out easily because the dependencies are explicitly known. Last but not least, the understanding of a PRV is improved by knowing directly which parameters have what influence. The new method is tested and verified by comparison with conventional non-linear numerical simulations.

Keywords: Components and systems, Modelling and Simulation

11:30 8881 Travis Wiens and Jeremy ven der Buhs, An Improved Transmission Line Model for Dynamic Laminar Flow Through Tapered Tubes

This paper presents an improved method for time-domain modelling of transient laminar flow through tapered tubes. This method is based on the transmission line method (TLM), a technique using transfer functions and delays to calculate the pressures and/or flows at the ends of the tube. However, unlike previous methods that are limited to non-tapered tubes or are inaccurate at low frequencies, the method presented here is applicable across a wide range of taper ratios, dissipation numbers, and frequency content. The new model is compared in the frequency domain to a boundary value problem solution and in the time domain to a method of characteristics solution.

Keywords: Modelling and Simulation

11:45 8913 Barbara Zardin, Giovanni Cillo, Massimo Borghi, Peter Zavadinka and Juraj Hanusovsky, Modelling and Simulation of a Cartridge Pressure Amplifier

Hydraulic pressure amplifiers of the cylinder type are much appreciated in hydraulic systems where high pressure work is needed only for a limited period of time, while during the remaining duty cycle the system operates at a standard level of pressure. The use of these elements allows the designer not to oversize the system, which will perform the work with a considerable power saving, confining the high pressure operation only on the side of the hydraulic cylinder. This works describes the modelling and simulation of a compact cartridge pressure amplifier for linear actuators. The cartridge amplifier is able to double or more the pressure in the system when needed and to not interfere during normal operation of the system. It has been designed to fit in the narrow space of the rod of normal hydraulic cylinder, being extremely

compact and efficient. Designing such a component and the study of the main design parameters influence have required a strong work of modelling and simulation, performed with a lumped parameters approach to depict the dynamic behaviour of the amplifier. This work illustrates the building of the model and a first comparison between simulated and experimental data. Moreover, the simulation activity is enlarged to analysis of the influence of some operating and design parameters on the amplifier dynamic behavior.

Keywords: Control, Digital and switched fluid power systems, Drives, transmissions and actuators, Efficient and intelligent systems, Fault analysis and diagnosis, Noise and vibration, Smart fluids and materials

12:00 8925 Pietro Marani, Cristian Ferrari and Massimo Milani, CFD Analysis of Compensator for Meter Out Sensing System

The Meter Out Sensing (abbreviated to MOS) system is a new hydraulic architecture for multi actuators systems based on meter out control and featuring regeneration. The main benefits of the system are the energy saving obtained by regeneration and the simplicity of operation for the absence of electronic controls and sensors. The regeneration and compensation are obtained through a new component called Three Way Compensator. This component compensates the pressure drop across the meter out edge of the hydraulic block, thus the flow rate is independent of the load. Moreover, regeneration is automatically enabled under proper operating conditions. The paper deals with the Computational Fluid Dynamic analysis for studying the control characteristics of the prototype of three way compensator. Since the system is fully hydraulic, the condition for regeneration depends from the load conditions primarily, but also from the pressure drops across the components generated by the fluid flow. Thus the amount of regeneration flow in a working cycle not only depends on the load but also on the flow rate. Moreover, the compensator, like all hydraulic valves, is affected by flow forces phenomenon. This can deviate the control characteristics from the expected behavior in particular by changing the force balance on the valve, thus its position. The knowledge of flow resistance characteristics and flow forces are crucial to understanding the control characteristics and the energy behavior of this new system. The results will enhance the design and will stimulate the further optimization this critical component. The numerical method is validated by comparison with experimental results obtained on the test bench.

Keywords: Efficient and intelligent systems, Fluid Power Systems, Modelling and Simulation, System design

Session 3: Digital and Switched Fluid Power Systems


14:00 8810 Giacomo Kolks and Jürgen Weber, Symmetric Single Rod Cylinders with Variable Piston Area? A Comprehensive Approach to the Right Solution

For most existing hydraulic systems, cylinders are a key selling point. In contrast to electric spindle drives, hydraulic cylinder drives offer an easy, robust and compact way of generating a translational motion for high load applications. However, unlike rotational hydraulic motors, cylinders do not offer a continuous variation of their displacement quantity. Though, multi-chamber cylinders provide a way of discrete variation of effective piston area and can be designed to act as a symmetric hydraulic actuator, despite only having one-sided piston rods.

Variation of effective piston area is beneficial in electro-hydraulic compact drives (ECD) in order to be able to switch the transmission ratio and thus exploit downsizing potential for the electric motor. ECD are displacement controlled cylinder drives with variable-speed motors in a compact unit with an enclosed oil circuit. They are an emerging technology, since machine manufacturers are increasingly in demand of modular and self-contained drive solutions with high energy efficiency – without abandoning the traditional benefits of hydraulic drives, such as robustness, power and flexible fail-safe behaviour. Being able to switch the transmission ratio adds another convincing argument for hydraulic drive technology in applications with a distinct separation between high force and rapid traverse strokes.

The proposed paper deals with actuator-based switching, which is based on allocating different cylinder displacement chambers to different pump ports or to a reservoir. Reallocating the ports by means of switching valves results in a new effective piston area by the principles of summation or subtraction. Also, the ratio of effective areas of acting and counter-acting chambers in double-acting cylinders will be treated in the paper. Being able to maintain a symmetrical cylinder enhances controllability and strongly facilitates integration into closed circuits with primary displacement control, such as ECD.

Although a lot of engineering effort has been carried out on multi-chamber cylinders, there is no comprehensive methodology known in literature yet that generates a valid solution space or that gives a guideline for synthesis of suitable multi-chamber cylinder structures. This paper proposes a systematic approach based on combinatorics to analyse all possible circuits and to help engineers make a choice of a suitable cylinder structure for their applications. Input requirements can be chosen to be transmission ratios, symmetry constraint and number of displacement chambers. The methodology is exemplarily applied to a demonstrator design of an ECD with variable transmission ratio of 3:1 with closed circuit, resulting in an innovative structure.

Keywords: Digital and switched fluid power systems, Drives, transmissions and actuators, Efficient and intelligent systems, Fluid Power Systems, System design

14:15 8829 Chenggang Yuan, Min Pan and Andrew Plummer, A Review of Switched Inertance Hydraulic Converter Technology

Digital hydraulics is a new technology providing an alternative to conventional proportional or servovalve-controlled systems in the area of fluid power. Research is driven by the need for highly energy efficient hydraulic machines but is relatively immature compared to other energy-saving technologies. Digital hydraulic applications, such as digital pumps, digital valves and actuators, switched inertance hydraulic converters (SIHCs) and digital hydraulic power management systems, all promise high energy efficiency. This review introduces the development of SIHCs and evaluates the device configurations, performance and control strategies that are found in current SIHC research, particularly focusing on the work being undertaken in last 15 years. The designs for high-speed switching valves are evaluated, and their advantages and limitations are discussed. This article concludes with some suggestions for the future development of SIHCs.

Keywords: Digital and switched fluid power systems, Fluid Power Systems

14:30 8858 Henrik B. Larsen, Magnus Kjelland, Per N. Lindholdt and Anders Holland, Digital hydraulic winch drives

This paper presents the planned use of digital displacement high torque low speed motors to drive large winches in off-shore and maritime applications. The digital displacement technology uses forced actuation of high- and low-pressure valves for each cylinder chamber, i.e. valves are opened and closed by actuation forces independently of cylinder pressure and supply pressures. The technology makes motors well suited for low speed secondary controlled operation including start and stop. It also enables un-loading of motor cylinders that are not needed to produce torque, whereby excellent efficiency at partial displacement is obtained. A research project on application of multi digital motors on a winch with lifting capacity in the 100t range is presented, and advantages of using such winch drives in off-shore and maritime lifting operations are discussed. Positioning and metering is a challenge in winch systems with traditional drives. A unique control scheme that allows very fine positioning of the motor shaft is presented. The performance of this method is shown in simulation and demonstrated with measurements on a motor.

Keywords: Components and systems, Control, Drives, transmissions and actuators, Efficient and intelligent systems, Fluid Power Systems

14:45 8866 Matti Linjama, Model-Based Control of a Digital Hydraulic Transformer-Based Hybrid Actuator

Energy-efficient motion control of hydraulic actuators is a challenging task. Throttle-free solutions have the potential for high efficiency. The main throttle-free approaches are pump-controlled systems, transformer-based solutions, and digital hydraulic solutions, such as switching transformers, multi-chamber cylinder and multi-pressure systems. This paper presents a novel solution based on a so-called digital hydraulic power management system (DHPMS). The DHPMS is freely rotating and a hydraulic accumulator is used for energy storage. In contrast to existing approaches, each actuator has its own DHPMS and a small accumulator to locally handle the power peaks. Only an average amount of power is needed from the hydraulic grid, radically reducing the size of the supply pump and the hydraulic piping and hosing. Pump flow is only 12.5% of the peak flow of the actuator in the case studied. Control of this type of system is challenging, and the model-based approach is used. The controller uses a simplified model and functionality is verified by using a detailed simulation model of the system. The results show that the approach is feasible but is demanding on the control valves. The system delay is also relatively long, which reduces the control performance in high-end systems. Nevertheless, this approach has potential in mobile machines, for example.

Keywords: Control, Digital and switched fluid power systems, Efficient and intelligent systems

Session 4: Applications of Fluid Power


15:45 8862 Magnus Landberg, Robert Braun, Magnus Sethson and Petter Krus, The Hydraulic Infinite Linear Actuator Applied to Elevators in Mid-Rise Buildings

Hydraulic elevators with conventional long-stroke hydraulic cylinders are limited for use in low-rise buildings, up to five floors. The benefits of such conventional cylinders are greatly reduced in taller buildings. A number of issues needs to be addressed in longer cylinders, like low hydraulic stiffness, low natural frequency, low hydraulic pressure and large oil volumes. Unfortunately for the hydraulic industry this sets a competitive edge to electromechanical drive train, which then becomes the dominant technology for elevators for mid-rise and high-rise buildings.

With a new hydraulic actuation technology jointly invented at Linköping University and SAAB named the Hydraulic Infinite Linear Hydraulic Actuator (HILA), these short-comings for hydraulic actuators can be reduced and hydraulic elevators can be offered for mid-rise buildings. The HILA technology provides long strokes, high system pressure, compactness and small chamber volumes. The actuator has a higher stiffness and a higher natural frequency compared

to conventional hydraulic cylinders. These characteristics are favourable in control design. The higher system pressure allows for an even more compact system design, with lower flow levels and a smaller reservoir.

The HILA technology combines two short-stroke cylinders with two engaging and disengaging clamping mechanisms into one actuator with long stroke length. The clamping mechanism by means of a hydraulic membrane is connecting the piston and the rod, when pressurised. By using simple logic valves for pressurizing, the piston and rod can be connected and disconnected with a secure and reliable clamping in a fast way. The motion of each single short-stroke piston linked together by the clamping mechanisms creates the motion of the piston rod. In this way the two pistons are moving along the rod in a kind of rope climbing motion.

The challenge is to implement a control system which can make use of all these characteristics and provide a smooth motion with constant elevator speed without unacceptable jerk at load shift as seen with ordinary directional valves. Earlier research work on HILA technology has shown that a control system with fast servo valves can fulfil these requirements.

This study shows results from system simulations using simulation analysis combined with optimization techniques. It is designed to evaluate how the comfort and endurance requirements can be achieved with HILA technology using slightly modified standard directional hydraulic valves.

Keywords: Digital and switched fluid power systems, Drives, transmissions and actuators

16:00 8889 Lasse Schmidt, Henrik Pedersen, Viktor Donkov and Torben Andersen, Analysis & Control of a Self-contained Hydraulic Winch Drive

This paper is considering the analysis and control of a self-contained hydraulic winch drive. Winch drives are used in various industries, and especially in offshore and marine applications such as fishing vessels, active heave compensation applications, cranes, oil- and gas drilling rigs, vessels for wind turbine installation and so forth. When high loads are present, such winches are typically actuated by use of hydraulics, and a main disadvantage of hydraulic actuation compared to electrical actuation is the potentially large installation space required due to the hydraulic power unit. In this paper the analysis of- and control design for a self-contained hydraulic winch drive is considered. The drive include a single supply pump, fixed displacement motor, flow control valve, a boot-strap reservoir and integrated boost-flow functionality. Emphasis is placed on the analysis of the highly coupled dynamics, an approach to decouple the dynamics and a robust control structure able to handle various types of loads. The properties are demonstrated through simulation results, when the system is subjected to a strongly varying external load and motion reference from an offshore wind turbine blade installation system.

Keywords: Control, Drives, transmissions and actuators, Fluid Power Systems, Modelling and Simulation

16:15 8890 Lauri Siivonen, Jyrki Tammisto, Kalevi Huhtala and Olli Tiainen, Hydraulic-Mechanic Damper Concept for Thruster Ice Impact Load Reduction

A novel hydraulic-mechanic damper was designed and dimensioned for damping of ice loads of a steerable thruster. The system consists of inertia masses and four hydraulic cylinders acting as spring and damping elements. The system is energy self sufficient and fail safe. Simulation model is used to study the damping potential and applicability of the system. Comparison between system with and without dampers showed clear advantages and potential for effecting the life time of the thruster gearbox.

Keywords: Components and systems, Fluid Power Systems, Modelling and Simulation, Noise and vibration, System design

16:30 8895 Jean-Charles Mare and Silvio Akitani, Foundation for Virtual Prototyping of Mechanical Power Management Functions in Actuators

Beside the main functions related to the control and transformation of power, safety-critical electromechanical actuators require many additional functions for power routing, protection and limitation. In practice, these functions are implemented mechanically because their realization at motor drive level is not acceptable for performance and reliability reasons. Contact forces play a major role in these mechanical devices (e.g. endstop, lock, brake, torque limiter, etc.), being either functional to serve the need, or parasitic due to their alteration of performance. The virtual prototyping of such mechanical power management functions therefore requires normal and tangent forces to be modelled with the right level of realism and reduced complexity. This communication provides some proposals to be used as foundation for the system-level modelling and simulation of these types of mechanical power elements that can be found in electromechanical actuators. Special focus is given to the model architecting, decomposition and block-diagram implementation, using the example of normal contact forces. The illustrative example concerns an integrated landing gear extension/retraction electromechanical actuator which embeds free-fall and autolock features. It shows how a well implemented single model (e.g. generic normal contact force model) combined with a right model decomposition can meet various modelling needs (e.g. droppable end-stop, lock and shearable axial stop). The proposed models are made compatible for integration in a 2x1D mechanical model architecture (axial and rotational motion) developed by the authors in previous reported work.

Keywords: Drives, transmissions and actuators, Modelling and Simulation, System design

16:45 8917 Andrea De Martin, Andrea Dellacasa, Giovanni Jacazio and Massimo Sorli, High-Fidelity Model of Hydraulic Actuators for Primary Flight Control Systems

Hydraulic actuators are the de facto standard for primary flight control systems, since they provide low jamming probability and intrinsic damping capabilities. Electro-Hydraulic Actuators theoretically provide a number of advantages over the traditional hydraulic systems, such as the decrease in the overall power consumption, easier installation and reduced weight of the flight control system, but are so far mostly used as back-up solutions in civil applications. Flight control actuators can face an extremely wide range of operational scenarios depending on the aircraft route, weather condition, pilot behaviour and components health. The use of high-fidelity models is instrumental in the design of both actuators and control laws and can enhance the definition of a Prognostics and Health Monitoring system, given its capability to simulate a huge number of possible in-flight situations. In this paper, we provide the mathematical definition of a novel high-fidelity model for primary flight control system, discuss its implementation and results in nominal and off-nominal conditions.


Session 5: Motion Control 1

Thursday 13th September 09:00 – 10:30

09:00 8835 Huan Yu, JianHua Wei, JinHui Fang, Ge Sun and Hangjun Zhang, Predictive Robust Control based on Higher-Order Sliding Mode for Passive Heave Compensator with Hydraulic Transformer

Passive heave compensation (PHC) system is widely applied in offshore equipment because of its superiority in energy conserving and reliability. However, it has poor adaptability to changing sea condition and the compensation accuracy is low. Hydraulic transformer (HT), working as a pressure-flow control element, can potentially solve the problems mentioned above. In this paper, an HT based PHC system is proposed for the first time, and a compensation algorithm based on higher-order sliding mode (HOSM) together with a prediction algorithm for the heave motion of the vessel is also proposed to get good compensation effect using the new PHC system. The prediction algorithm is proved to be effective according to the measured data of sea trials, and reduce the difficulty of designing and parameter tuning process compared with the existing ones. The effectiveness of the proposed control algorithm is evaluated with simulation, moreover, the effectiveness can still be maintained under changing sea condition which is also verified by simulation. Key words: passive heave compensator, hydraulic transformer, heave prediction, high order sliding mode

Keywords: Components and systems, Digital and switched fluid power systems, Drives, transmissions and actuators, Efficient and intelligent systems, Fault analysis and diagnosis, Noise and vibration, Smart fluids and materials

09:15 8841 Pauli Mustalahti and Jouni Mattila, Nonlinear Model-Based Controller Design for a Hydraulic Rack and Pinion Gear Actuator

Hydraulic manipulators are extensively utilized to move heavy loads in many industrial tasks. In commercial applications, a manipulator base is required to rotate a motion range of the full 360°. This is usually implemented by using a hydraulic rack and pinion gear actuator. Due to the manipulator’s long reach and heavy loads, manipulator tip acceleration can produce significant torque to the rotation gear in free-space motion. Imposed by nonlinear dynamical behavior (involving, e.g., the gear backlash and actuator friction) added to high inertia, a system closed-loop control design becomes a challenging task. An advanced closed-loop control enables to increase the automation-level of hydraulic manipulators. This study designs a novel subsystem-dynamics-based controller for a hydraulic rack and pinion gear actuator utilizing the control design principles of the virtual decomposition control (VDC) approach. An adaptive backlash compensation is incorporated in the control design. Furthermore, the proposed controller is implemented in previously-designed state-of-the-art hydraulic manipulator control. The stability of the overall control design is proven. Experiments with a full-scale commercial hydraulic manipulator demonstrate the effectiveness of the proposed adaptive backlash compensation and the overall control performance.

Keywords: Control, Modelling and Simulation

09:30 8847 Jarmo Nurmi, Mohammad M. Aref and Jouni Mattila, A Neural Network Strategy for Learning of Nonlinearities Toward Feed-Forward Control of Pressure-Compensated Hydraulic Valves with a Significant Dead Zone

A velocity feed-forward-based strategy is an effective means for controlling a heavy-duty hydraulic manipulator; in particular, a typical valve-controlled hydraulic manipulator, to compensate for valve dead-zone and other hydraulic valve nonlinearities. Based on our previous work on the adaptive learning of valve velocity feed-forwards, manually labelling and identifying the dead-zones and the other nonlinearities in the velocity feed-forward curves of pressure-compensated hydraulic valves can be avoided. Nevertheless, it may take two to three minutes or more per actuator to identify a pressure-compensated valve's highly nonlinear velocity feed-forward in real-time with an adaptive approach, which

should be reduced for realistic applications. In this paper, inspired by brain signal analysis technologies, we propose a new method based on deep convolutional neural networks comparing with the previous method to significantly reduce this online learning process with the strong nonlinearities of pressure-compensated hydraulic valves. We present simulation results to demonstrate the effectiveness of the deep learning-based learning method compared to the previous results with an adaptive control-based learning.

Keywords: Control, Fault analysis and diagnosis, Modelling and Simulation

09:45 8863 Hongzhao Zhou, Andrew Plummer and David Cleaver, Closed Loop Position and Pre-stress Control for a Morphing Aircraft Wing with Distributed Multi-axis Pneumatic Actuation This paper presents the design and control of a morphing wing structure using an active tensegrity structure. A tensegrity structure, which is a set of compressive members (struts) stabilized by a set of tensile members (cables) is a good basis for creating a lightweight active structure, due to its potentially high stiffness-to-weight ratio, and the ease with which actuators can be embedded by replacing selected members in the structure. In this work, a multi-axis control scheme is developed for closed loop control of the shape and internal force (pre-stress) of the structure. An experimental prototype has been built, with 6 unidirectional pneumatic cylinders controlled by pulse-width-modulated switching valves. Shape change in terms of twisting and span-wise bending are demonstrated, and an optical motion tracking system is used to help investigate the dynamic position control of the structure. The structure can achieve ±15° twist change for wing angle of attack or ±10° span-wise bending in a 300mm span length. By simultaneously controlling the structural pre-stress, the geometric stiffness of the structure can also be varied. Future research is discussed, which will involve embedding the active structure in a wing aerofoil and testing in a wind tunnel.

Keywords: Components and systems, Control

10:00 8870 Niels Christian Bender, Henrik Pedersen, Torben Andersen and Michael Bech, A Multi-agent Evolution Algorithm for Input shaping of a Repetitive Non-linear Dynamic System

This paper explores the challenges regarding designing a heuristic control algorithm for a dynamic non-linear system with multiple inputs and outputs. The presented algorithm aims to shape the voltage input (both magnitude and timing) applied to fast switching valves in a Digital Displacement unit. This consists of multiple sub-systems, where optimal decisions must be made, based on the system design and performance criteria. In this regard good performance are defined as: low electrical energy required for switching, accurate switching timing and low plunger velocity near the seat. The proposed algorithm examines the design-space in a user-defined manner combined with stochastic decision making. The randomness of the algorithm is based on the standard deviation between located elite designs. This reveals several feasible input sequences to achieve the goal, and the optimums are benchmarked with a differential evolution algorithm. The techniques are demonstrated by simulation and the results compared showing similar performance of the optimums.

Keywords: Control, Digital and switched fluid power systems, Fluid Power Systems

Session 6: Motion Control 2


11:00 8868 Nils Trochelmann, Phillip Bischof-Stump, Frank Thielecke, Dirk Metzler and Stefan Bassett, A Robust Pressure Controller for a Variable Speed AC Motor Pump - Application to Aircraft Hydraulic Power Packages

Highly integrated electro-hydraulic power packages with electric motor-driven pumps (EMP) are a key technology for future aircraft with electric distribution systems. State of the art aircraft EMPs are robust but lack efficiency, availability, and have high noise emissions. Variable speed fixed displacement (VSFD-) EMPs, combining a permanent magnet synchronous motor and an internal gear pump, show promising properties regarding noise reduction and energy efficiency. Though, meeting the strict dynamic requirements is tough with this EMP-concept. Speed limitations and inertia impose strong restrictions on the achievable dynamic performance. Moreover, the requirements must be met under a wide range of operating conditions. For a prototype aircraft VSFD-EMP a robust pressure controller design is proposed in this paper. In a first step the operating conditions of the EMP are defined, analyzing environmental conditions and impacts of the interfacing aircraft systems. Nonlinear and linear control design models are developed and validated by measurements at an EMP test rig built for this project. A conventional cascade pressure control concept is selected. This is motivated by the demand for simple, reliable, and proven solutions in aerospace applications. A controller is designed by applying classical loop shaping techniques. Robust stability and performance of the system are investigated through a subsequent μ-analysis. Finally, the controller is tested under nominal and worst case conditions in nonlinear simulations.

Keywords: Components and systems, Control, Efficient and intelligent systems, Fluid Power Systems, Modelling and Simulation, System design

11:15 8877 L. Viktor Larsson and Petter Krus, A General Approach to Low-Level Control of Heavy Complex Hybrid Hydromechanical Transmissions

This paper focuses on the low-level control of heavy complex hydraulic hybrids, taking stability and the dynamic properties of the included components into account. A linear model which can describe a high number of hybrid configurations in a straightforward manner is derived and used for the development of a general multiple input multiple output (MIMO) decoupling control strategy. This strategy is tested in non-linear simulations of an example vehicle and stability requirements for the low-level actuators are derived. The results show that static decoupling may be used to simplify the control problem to three individual loops controlling pressure, output speed and engine speed. In particular, the pressure and output speed loops rely on fast displacement controllers for stability. In addition, it was found that the decoupling is facilitated if the hydrostatic units have equal response. The low-level control of heavy complex hydraulic hybrids may thus imply other demands on actuators than what is traditionally assumed.

Keywords: Control, Drives, transmissions and actuators, Fluid Power Systems

11:30 8896 Siavash Danaee, Jarmo Nurmi, Tatiana Minav, Jouni Mattila and Matti Pietola, Direct Position Control of Electro-Hydraulic Excavator

Position measurement in the electro-hydraulic systems is feasible via the utilization of physical sensors. An improvement in technology has led to the manufacturing of high accurate position sensors for direct position control. This paper proposes utilization of direct position control in an electro-hydraulic system with a new hydraulic zonal system architecture implemented with Direct Driven Hydraulics. It was mentioned in early study that this hydraulic system architecture as a replacement for the traditional valve-based hydraulic systems, has higher energy efficiency rate. In this study, the simulation implementation and experimental verification of Direct Driven Hydraulics (DDH) will be investigated for a micro excavator test case from position control point of view. Results demonstrated that the implementation of DDH in an excavator case will lead to maximum 5 cm error in a single-cycle movement.

Keywords: Control, Fluid Power Systems, Modelling and Simulation

11:45 8935 Sangyoon Lee and Perry Li, Supervisory Control for a Switched Mode Hydraulic Transformer

A supervisory control for a hydraulic transformer is developed. The hydraulic transformer being controlled is configured in a traditional manner where a pair of hydraulic pump/motors are mechanically coupled together. This transformer can be configured in three distinct modes depending on how each port is connected. A supervisory control determines, for the desired output pressure and output flow, the mode and shaft speed that the transformer should operate in order to minimize the power loss. The resulting controller structure ensures that the transformer provides the desired flow while following the desired mode and shaft speed. The supervisory control is further modified to avoid high-frequency switching and to achieve bumpless transfer between modes. Experimental results demonstrate the efficacy of the supervisory controller to increase the efficiency of the hydraulic transformer driven system.

Keywords: Control, Digital and switched fluid power systems, Efficient and intelligent systems

12:00 8938 Addison Alexander, Annalisa Sciancalepore and Andrea Vacca, Online Controller Setpoint Optimization for Traction Control Systems Applied to Construction Machinery

The development of a suitable traction control system for off-road heavy machinery is complicated by several different factors, which differentiate these machines from typical on-road systems. One such difficulty arises from the fact that they are often operated on ground conditions which can vary widely and rapidly. Due to this, traction control systems designed for these vehicles must be robust to a large array of surface types, and they must be capable of reacting quickly to significant changes in those types. In order to accomplish this, this paper proposes an online parameter optimization technique suitable for tuning the setpoint of a control system to maximize the tractive potential of a construction vehicle in real time. The traction control principle itself is based on selectively braking wheels which are slipping. It also attempts to account for the interactions of the transmission systems that deliver power from the engine to the wheels. This research uses a wheel loader as a reference machine for assessing controller performance. Drawing on previous work in simulation and controller design, a system model was developed which incorporates the vehicle dynamics of the machine as well as the behavior of the electrohydraulic brakes. This system model was leveraged to understand the effect of different optimization schemes on the performance of the traction control.

The self-tuning algorithm is based on a compound optimization method utilizing both a system identification component and a parameter tuning component. The first part optimizes the model parameters to fit it as well as possible to measured slip-friction data. Based on the results of this, the second part draws from theories of wheel traction to maximize a balance of pushing force and traction effectiveness. The result is a method which can achieve the proper setpoint based on real-time data describing the ground condition. This system was run first in simulation and then on a modified vehicle system. In both cases, the algorithm allows the controller to find better setpoints to improve the traction control performance online.

Keywords: Control, Efficient and intelligent systems, Modelling and Simulation, System design

Session 7: System Design, Fault Analysis and Diagnosis


14:00 8802 Karl Uebel, Henrique Raduenz, Petter Krus and Victor De Negri, Design Optimisation Strategies for a Hydraulic Hybrid Wheel Loader

This paper deals with design optimisation of hydraulic hybrid drivelines during early concept design phases. To set the design parameters of a hybrid driveline such as gear ratios, pump/motor displacements and size of energy storage, the energy management of the hybrid machine needs to be considered as well. This is problematic since a nested design and control optimisation normally requires substantial computer power and is time-consuming. Few previous studies have treated combined design and control optimisation of hydraulic hybrid vehicles using detailed, non-linear component driveline models. Furthermore, previously proposed design optimisation methods for on-road vehicles are not suitable for heavy off-road machines operating in short repetitive cycles with high transient power output. The paper demonstrates and compares different optimisation approaches for design and control optimisation combining deterministic dynamic programming and non-gradient based numerical optimisation. The results show that a simple rule-based energy management strategy can be sufficient to find the optimal hardware design even though non-optimal control laws are used.

Keywords: Fluid Power Systems, Modelling and Simulation, System design

14:15 8805 Junxia Guo, Jianfeng Tao, Lin Li and Chengliang Liu, Diagnosis Method for Valve-controlled Hydraulic Cylinder Leakage Based on Subspace Identification

This paper proposes a fault diagnosis method based on subspace identification for the leakage fault detection of valve-controlled hydraulic cylinders. Firstly, the state-space model for the system is established, in which the external force on the piston of the hydraulic cylinder is selected as input signal, and the pressure of the two chambers, displacement and velocity of piston rod are chosen as state variables. Then, the estimation value of specific elements of the system matrix can be obtained in terms of the subspace identification theory. On this basis, the existence, type and level of the leakage fault are determined. Finally, the numerical simulation is conducted through MATLAB-Simulink to verify the proposed method. The results demonstrate that the proposed method is effective and has high accuracy.

Keywords: Fault analysis and diagnosis, Modelling and Simulation

14:30 8808 Paolo Casoli, Andrea Bedotti, Mirko Pastori and Antonio Lettini, Condition Monitoring Based on Thermodynamic Efficiency Method for an Axial Piston Pump

In the last years, the interest in the field of Prognostics and Health Management (PHM) has been growing in many industrial fields. The objective of PHM is to switch from a time-based (scheduled) maintenance to a predictive maintenance with advantages in terms of reliability and safety. This paper presents the thermodynamic method for the fault detection of an axial piston pump which is a critical component in many hydraulic systems; the method was developed for the evaluation of the overall efficiency which is an important parameter to monitor the machine health state. Through the measurements of temperatures and pressures at suction and delivery ports the method allows to calculate the efficiency avoiding the use of costly sensors, such as speed and torque sensors. The paper investigates the possibility of utilizing the pump overall efficiency evaluated through the thermodynamic method as a reliable parameter for the fault detection. The machine under study is a variable displacement axial-piston pump with external drainage equipped with a load sensing regulator. The thermodynamic method was already validated in a previous work by comparing it with the standard approach, based on the direct measurement of the mechanical power. The proposed method requires the measurement of the delivery and drain flow rates involving the use of expensive flowmeters which could prevent its usage in online applications; this limit should be overcome with the development of low-cost solutions for flow rate measurements. A preliminary investigation of the pump failure modes was conducted to identify the most important faults which need to be considered. An experimental campaign was carried out on a laboratory test bench with the pump in the flawless state and in faulty states. The faulty states were realized by introducing components with artificial faults into the pump. The pump was accurately instrumented to monitor all the main variables, i.e. pressures, temperatures, flow rates, swash plate angle and shaft torque and speed. Different operating conditions were considered and each test was repeated several times in order to acquire a suitable population to verify the repeatability of the data. The experiments demonstrate the method capability of detecting some but not all of the incipient faults tested in steady-state conditions as a consequence of temperature variations which have the most important influence on efficiency estimation. Future works will include the development of innovative solutions to measure flow-rates and the testing of other faults to further verify the reliability of the method.

Keywords: Fault analysis and diagnosis

14:45 8833 Raphael Alt, Justus Malzahn, Hubertus Murrenhoff and Katharina Schmitz, A Survey of Industrial Internet of Things in the Field of Fluid Power - Basic Requirements for Plug-and-Play

The Internet of Things (IoT) describes the fusion of computational power (embedded systems) and mechatronic systems establishing an internet based network of machinery. Various industrial branches are influenced, reaching from the energy sector (smart grids) over the field of consumer products (smart home, smart phone, ..) to the manufacturing industry, the “Industrial Internet of Things” (IIoT). The modern Information and Communication Technologies (ICT) of IIoT set up the foundation in order to overcome the former conflicting objectives of high productivity on the one side and a highly individual production at low manual effort in planning, development and adaption on the other side. Within the production industry, commissioning of a machine is still representing a very challenging operation. For the first time, various subsystems of different manufacturers are supposed to work cooperatively in a new environment. Due to the vast variety of systems-configurations thus resulting in individual commissioning events, the majority of steps are executed manually by commissioning engineers. In this paper an approach to integrate and automate the commissioning of a Fluid Power machine based on new ICT is presented. This use-case is known as “Plug-and-Play” or “Plug-and-Produce”. The principle of this method originates from the field of distributed systems (i.e. Internet) and is modified to fit industrial applications. As a key concept, the commissioning is divided into generalised tasks, which can be distributed and executed by available system participants subsequently. This concept sets up new requirements to the system participants which are pointed out in more detail. Equipped with additional technological abilities, such as basic communication, self-description and digital services, former intelligent field devices become cyber-physical systems (CPS). Finally, a draft of the entire Plug-and-Play process is shown by the example of an electro-hydraulic actuator (EHA), providing a general understanding of the main requirements and opportunities of Industrial Internet. Furthermore, the demand of action on specific domains can be deduced and thus delivers indications for upcoming research developments.

Keywords: Components and systems, Efficient and intelligent systems, Fluid Power Systems, System design

15:00 8864 Paolo Tamburrano, Riccardo Amirante, Elia Distaso and Andrew Plummer, A Novel Piezoelectric Double-Flapper Servovalve Pilot Stage: Operating Principle and Performance Prediction

This paper proposes a novel architecture for the pilot stage of electro-hydraulic two-stage servovalves that does not need a quiescent flow and a torque motor as well as a flexure tube to operate. The architecture consists of two small piezoelectric valves, coupled with two fixed orifices, which allow variation of the differential pressure at the main stage spool extremities in order to move it with high response speed and accuracy. Each piezoelectric valve is actuated by a piezoelectric ring bender, which exhibits much greater displacement than a stack actuator of the same mass, and greater force than a rectangular bender. The concept is intended to reduce the influence of piezoelectric hysteresis. In order to assess the validity of the proposed configuration and its controller in terms of spool positioning accuracy and dynamic response, detailed simulations are performed by using the software Simscape Fluids. At 50% amplitude the -90° bandwidth is about 150Hz.

Keywords: Servovalve, Piezoelectric, Ring bender, Simscape, Control, Drives, transmissions and actuators, Fluid Power Systems

Session 8: Rheology, Tribology and Cavitation


16:00 8807 Philipp Weishaar, Alexander Görres, Hubertus Murrenhoff and Katharina Schmitz, Investigating Electrostatic Flow Charging using a Small Scale Test Bench

Common examples for electrostatic discharges can be encountered in everyday life. When approaching a grounded surface after walking on insulating flooring material or while riding an escalator one might experience an electrostatic discharge first hand. These discharges generally do not pose a problem but when translated to various fields of engineering, such as in hydraulics, discharges can be the root cause for system failures. The pioneering fields of engineering for electrostatic charging in systems are petro-chemistry and electrical engineering. Researchers in both fields attempted to formulate models to calculate the electrostatic charging a priori. These models provide some indication regarding the magnitude of charge but are currently not suited for the application in hydraulic systems. This is due to the lack of necessary fluid and material parameters for the application of either one of the models. [1, 2] Previous work in the pioneering fields focused on fluids and materials typical for their respective applications. This paper seeks to take the first step to remedy this situation by developing and commissioning a test bench for investigating a wide variety of hydraulic fluid material combinations. The fluids pending investigation range from a typical hydraulic fluid based on a group I base oil to a pure polyalphaolefine of group IV. Common materials for hydraulic systems are investigated with a small scale test bench as well, such as steel and brass common to hydraulic applications as well as plastics and rubbers. In order to conduct these investigations a Searle viscometer is presented in this paper. In a Searle viscometer the cylinder is rotating while the cup or pipe remains stationary. Initially this paper gives the necessity for a small scale test bench using

experimental results of an existing large scale test rig. Subsequently, the design of a small scale test bench, the Searle viscometer, will be presented along with a method for measuring the charge density. The small scale test bench is based on the work of Washabaugh and is able to generate the necessary information required for using the chemical reaction-based model [3, 4]. The main feature of the chemical reaction based model is the consideration for different material and fluid influences, beyond the scope of viscosity and system geometry.

Keywords: Smart fluids and materials

16:15 8815 Felix L. Fischer, Julian Bartz, Katharina Schmitz, Ludwig Brouwer and Hubert Schwarze, A Numerical Approach for the Evaluation of a Capillary Viscometer Experiment

The dynamic viscosity of a fluid is an important input parameter for the investigation of elastohydrodynamic contacts within tribological simulation tools. In this paper, a capillary viscometer is used to analyse the viscosity of a calibration fluid for diesel injection pumps. Capillary viscometers are often used for the determination of viscosities that show a significant dependence on shear rate, pressure and temperature such as polymer melts or blood. Therefore most of the research on corrections of measured viscosities have been made using polymer melts. A new method is presented to shorten the effort in evaluating the capillary experiment. The viscosity itself can be calculated from experimental data. Essential parameters are the radius of the capillary, its length, the capillary flow and the pressure difference over the capillary. These quantities are used in the Hagen-Poiseuille equation to calculate the viscosity, assuming laminar and monodirectional flow. According to said equation, the viscosity depends on the geometry and the pressure gradient. A typical capillary viscometer contains three main flow irregularities. First the contraction of the flow at the capillary inlet, second the expansion of the flow at the capillary outlet and third the inlet section length of the flow after which the velocity profile is fully developed. These flow phenomena cause pressure losses, which have to be taken into account, as well as the altered length of the laminar flow in the capillary. Furthermore, the temperature difference over the capillary also affects the outlet flow. Therefore, in this paper, a newly developed method is proposed, which shortens the effort in pressure and length correction. The method is valid for viscometers, which provide a single phase flow of the sampling fluid. Furthermore, the proposed correction is suited for arbitrary geometries. A numerical approach is chosen for the analysis of the experiment. In order to facilitate the experimental procedure of a capillary viscometer, a special algorithm was developed. The numerical approach uses a static CFD simulation, which is recursively passed through. If a termination condition, regarding the pressure difference between two cycles, is fulfilled, the real viscosity can be calculated in the usual way from the Hagen-Poiseuille equation. A special advantage of the proposed experimental evaluation is the general applicability for arbitrary geometries. In this paper, the procedure is validated with a well-known reference fluid and compared to data, which was gathered from a quartz viscometer experiment with the same fluid. Therefore, experiments are conducted with the capillary viscometer and compared at various pressure and temperature levels.

Keywords: Components and systems, Drives, transmissions and actuators, Fluid Power Systems, Smart fluids and materials

16:30 8872 Filipp Kratschun, Tobias Mielke and Katharina Schmitz, Water Vapour Cavitation in Hydraulic Fluids

Cavitation in hydraulic systems leads to cavitation erosion which ultimately results in system failure. The phenomenon has been known for decades, yet its physical background is still not fully understood. There are three types of cavitation known: gas, vapour and pseudo cavitation. While in the latter case gas bubbles already exist and change in size due to the pressure variation, the other cavitation types produce bubbles or enlarge existing ones by mass transport mechanisms. In the case of gas cavitation, air is released from the fluid due to lowered solvability of the fluid, whereas vapour cavitation describes the evaporation of the surrounding fluid inside the bubble. In previous gas-cavitation studies enormous air release rates in hydraulic fluids have been discovered which could not be explained just by the diffusion of dissolved air through bubble boundary’s. A possible explanation is the simultaneous occurrence of vapour cavitation in conjunction with gas-cavitation /Ibe15/ and /Fre15/. However, this requires drastic pressure drops below few Pa, which is hard to achieve in hydraulic systems. The authors suggest a further explanation for the unexplainable air release rates. This article suggests a fourth type of cavitation. Technical fluids can dissolve other fluids, such as water, to a certain degree. If these have a significantly higher vapour pressure than the base fluid they evaporate at a much higher pressure compared to the base fluid. Based on a standard HLP 46 hydraulic oil and water as dissolved fluid, the presented hypothesis is verified. Firstly, a phenomenological mathematical model is developed that takes into account not only the gas cavitation of the dissolved air but also the formation of bubbles due to the dissolved water. Subsequently, a test rig is presented to prove the hypothesis. This consists of an airtight container in which oil with a specified humidity is poured. After setting a defined temperature, the air volume over the oil is suddenly sucked off. Following this, the resulting increase in pressure is measured. The water in the oil evaporates and causes a faster increase in pressure than a dry oil ultimately leading to a higher air release rate. In addition, the change in humidity in the oil is measured. Finally, the experimental results for the fluid pair HLP 46 / water are presented and compared with the developed model.

/Fre15/ Freudigmann, H. A. , Iben, U., Pelz, P.F. Air release measurements of V-oil 1404 downstream of a micro orifice at chocked flow conditions, 9th International Symposium on Cavitation, Lausanne, Swiss, 2015 /Ibe15/ Iben, U. et al. Optical measurements of gas bubbles in oil behind a cavitating micro orifice flow, Springer-Verlag Berlin Heidelberg, 2015

Keywords: Fluid Power Systems, Modelling and Simulation

16:45 8904 Haihang Wang, He Xu, Zitiong Zhao, Vishwanath Pooneeth and Liye Jiao, Development of Visualized Water Hydraulic Experiment System for Studying the Bubble Flow Pattern Inside Valve

To study the flow pattern mechanism of cavitation and erosion in water hydraulic valves, a visualized water hydraulics experiment for testing the bubble flow was designed and conducted in this paper. An ergonomic design method was adopted to ensure with the characteristics of the visualized experiment platform of being modular, movable, networked, adopting a virtual three-dimensional vision and safety, respectively, were adhered. An experimental video acquisition subsystem with an optimized arrangement of 5plane mirrors was presented to observe and analyze the bubble flow pattern in a transparent hydraulic valve. An algorithm was developed to extract the 2-D bubble features and reconstruct the 3-D bubble flow pattern. The 2-D and 3-D calculated results were analyzed, which effectively reconstructed the bubble flow. During the 2-D and 3-D results analysis for a selected period of time, the visualized water hydraulics experiment system in this paper met the expected performance requirements.

Keywords: Components and systems, System design

17:00 8933 Jannik Hartwig Jakobsen and Michael Rygaard Hansen, Synthetic Esters and Dynamics of Pressure Compensated Proportional Directional Control Valves

The purpose of this paper is to help reduce the uncertainty in behavior introduced when changing hydraulic oil from mineral oil (HLP) to biodegradable oil (synthetic esters - HEES) by comparing the behavior of proportional valves with HLP and with HEES at various temperatures. The focus of this article is on classic proportional valves used in the industry. The study is based on tests and modelling with characterization of dynamic behavior in mind. The characterization is based on tests of two pressure compensated proportional valves, one with closed loop control of the spool position, and one without. The two ester types tested are one based on a saturated, fully synthetic ester and a regular fully synthetic ester. The tests consist of steps and frequency responses. Both valves are tested at oil temperatures 20°C, 40°C and 60°C. The adopted models are based on a third order linear model with parameters identified using frequency responses from actual valve tests. The variation of amplitude and bias has some influence on the resulting frequency response especially at lower temperatures. But the general tendencies are unaffected by amplitude and bias. As expected a clear tendency for both valves of increasing dampening at decreasing temperatures is seen regardless of oil type, but the increase in dampening is similar for all oil types. The saturated ester leads to less bandwidth at lower temperatures for both valves, but the overall variations between all oil types stay within 1.66Hz of each other when tested with the same test parameters. The investigation indicates that the difference in dynamic characteristics at 20°C caused by the different oil types can not be explained with variations in any single one of the classic liquid properties density and viscosity and more investigations are needed to identify the cause.

Keywords: Components and systems, Fluid Power Systems, Modelling and Simulation, Smart fluids and materials, System design

Session 9: Piston Pumps and Motors


09:00 8822 Yapeng Xu, Kai Guo, Jianfeng Li and Keyu Wang, The Torque on the Swashplate of Axial Piston Variable Displacement Pumps with Conical Cylinder Blocks

In this paper, the load torque on the swashplate of axial piston variable displacement pumps with conical cylinder blocks is studied. At present, general analytical solution for the load torque of axial piston variable displacement pump is not available, which makes the dynamic analysis and controller design an uneasy work. The main contribution of this paper is that the analytical solution of the swashplate torque caused by piston inertia and centrifugal force was derived. First, based on the piston acceleration and centrifugal force, the piston kinematic and dynamic models were developed, the analytical solution of the swashplate torque caused by piston inertia and centrifugal force was derived. In addition, the piston chamber pressure dynamics were established, the pressure distribution in the cylinder bore and the load torque of the swashplate under different working conditions were obtained. Finally, the relationship between the swashplate average load torque and the swashplate angle, swashplate angular velocity, pump load pressure and the pump input shaft velocity was uncovered. It is shown that the swashplate angle has greater influence on the load torque when the pump load pressure is higher, besides, it is interesting to observe that the swashplate angular velocity has a damping influence upon swashplate dynamics which helps to stabilize the swashplate during pump displacement regulation transients.

Keywords: Components and systems, Control, Fluid Power Systems, Modelling and Simulation

09:15 8825 Nathaniel J. Fulbright and James D. Van de Ven, Dynamic Response of Pressure Compensated Variable Displacement Linkage Pump

The Variable Displacement Linkage Pump (VDLP) uses an adjustable planar linkage to vary the displacement of the piston. Previous work focused on dynamic modeling of the pump at fixed displacements and therefore did not account for the displacement control method or the dynamics of changing displacement. One key application of the VDLP is in pressure compensated, high-pressure water hydraulics. This paper expands on previous modeling work to include the behavior of the hydro-mechanical pressure compensation valves and the displacement control linkage. The multi-domain dynamic model captures the fluid dynamics in the pumping chambers and poppet-style control valves; the dynamics of the control valves; and the kinematics and kinetics of the two degree-of-freedom nine-bar pump linkage. The dynamic model was exercised in a simulation of the pump responding to changing demands in the output flow rate. Simulation results showed that quick response times of 100 milliseconds to a step in the load were achieved. Overshoot of the displacement is damped using an orifice in the control line. A physical prototype of the VDLP was used to validate the simulation results.


09:30 8832 Peter A J Achten, Jeroen Potma and Jasper Achten, Low Speed Performance of Axial Piston Machines

Low speed operation of axial piston motors has always been a critical performance issue. The breakaway torque determines the capacity of a motor to move a certain load from standstill conditions. In addition, the low speed performance has also become a critical performance parameter for pumps being applied in frequency controlled electro-hydraulic actuators. Yet, there is almost no information available about the low speed and breakaway characteristics of piston pumps and motors.

A new test bench has been constructed to measure these characteristics. The new bench allows operation of hydrostatic machines below 1 rpm, down to 0.009 rpm. At these conditions, the main tribological interfaces operate in the solid friction domain, at which the friction losses are at a maximum value.

This research describes and analysis the test results for a number of different axial piston pumps and motors: two slipper type motors, one slipper type pump and a floating cup pump/motor. The tests have been performed at various operating pressures and operating speeds. Furthermore, the breakaway torque has also been measured after letting the hydrostatic motor stand still for one or more days.

Keywords: Components and systems, Efficient and intelligent systems, Fault analysis and diagnosis

09:45 8937 Liselott Ericsson and Jonas Forssell, A Novel Axial Piston Pump/Motor Principle with Floating Pistons - Design and Testing

This work presents a method of estimating a flow loss within the discharge flow of a pressure controlled axial piston pump. A noticeable drop in flow efficiency can be seen due to flow losses in hydraulic pumps. Estimates of loss parameters are computed utilizing a nonlinear, first order model of the discharge pressure of the pump and an extended Kalman filter (EKF) with parameter estimation with a single measurement for the EKF. The experimental setup consists of the pump, the implement valve to control flow to the load, and a cylinder setup that can be approximated by a double rod cylinder. A valve has been added to the discharge flow with variable valve area to create different flow losses. Two pressure reducing valves, one for each half of the cylinder, has been introduced to vary load pressure. Experimental measurements include discharge and load pressure, as well as discharge flow, discharge flow loss, swash plate position, and measurements to determine the implement valve position. Instead of modeling the load pressure, swash plate angle, and implement valve dynamics, they have been included as parameters of the discharge pressure model. The discharge pressure is the only measurement in the EKF algorithm. Experimental testing included combinations of the following: varying hydraulic drive motor speed, varying flow loss valve area, varying load pressures, and varying implement valve area. Flow loss is characterized by low Reynolds flow and high Reynolds flow. A single state is appended to the first order model utilized in the EKF to do real time estimation of either the low Reynolds flow parameter or the high Reynolds flow parameter, as well as the discharge pressure. The EKF result for the discharge pressure estimation is compared to the measured pressure. The estimation result for the flow loss parameter is compared to a general least squares fit of a parameterized model of the sum of flows within the discharge volume, where the high Reynolds flow and low Reynolds flow coefficients are the unknown parameters of the general least squares fit. Results show that changes in flow losses can be detected by the algorithm which could be implemented in real-time for use in detecting changes in the pump due to wear or damage exhibited as a flow loss.

Keywords: Fluid Power Systems

Session 10: Vane and Gear Pumps and Motors


11:00 8857 Ryan Jenkins and Monika Ivantysynova, An Empirically Derived Pressure Compensation Control System for a Variable Displacement Vane Pump

Pressure compensated vane pumps are well suited to applications such as automatic transmissions which require a low-cost, compact solution to provide the hydraulic power required for clutch control as well as the lubrication and cooling functions. This paper presents a black-box model of the series of valves providing the flowrate to control the motion of the pivoting cam in a variable displacement vane pump from an automatic transmission application. This series of valves consists of a pressure-reducing valve followed by a solenoid-operated valve that generates a pilot pressure acting on the main pressure regulator valve to adjust the commanded pump outlet pressure setting. Valves taken from a transmission control block were integrated into a custom unit and installed on a test rig with a modified vane pump. Measurements previously collected on this test rig were used to validate a lumped-parameter vane pump model and provide data containing the input-output relationships of the pressure compensation system valves. An analysis of the black-box description of this control system identifies limitations to the achievable system performance. This analysis reveals that the low-cost solenoid-operated valve and the arrangement of the valves within the control circuit both contribute to a controllable bandwidth less than 2Hz. Finally, the paper presents an alternate control system design capable of improved system performance.

Keywords: Components and systems, Control, Drives, transmissions and actuators, Modelling and Simulation

11:15 8876 Andrew Robison and Andrea Vacca, Multi-Objective Geometric Optimization of Elliptical-toothed Gerotor Pumps for Kinematics and Wear by Genetic Algorithm

A computationally efficient gerotor gear generation algorithm has been developed that creates elliptical-toothed gerotor gear profiles, identifies conditions to guarantee a feasible geometry, evaluates several performance objectives, and is suitable to use for geometric optimization. Five objective functions are used in the optimization: minimize pump size, flow ripple, adhesive wear, subsurface fatigue (pitting), and tooth tip leakage. The gear generation algorithm is paired with the NSGA-II optimization algorithm to minimize each of the objective functions subject to the constraints to define a feasible geometry. The genetic algorithm is run with a population size of 1000 for a total of 500 generations, after which a clear Pareto front is established and displayed. A design has been selected from the Pareto front which is a good compromise between each of the design objectives and can be scaled to any desired displacement. The results of the optimization are also compared to two profile geometries found in literature. Two alternative geometries are proposed that offer much lower adhesive wear while respecting the size constraints of the published profiles and are thought to be an improvement in design.

Keywords: Components and systems

11:30 8902 Divya Thiagarajan and Andrea Vacca, Modeling of the Lateral Lubricating Interfaces in External Gear Machines Considering the Effects of Cavitation This work presents a novel approach to evaluate the cavitating conditions encountered in the lateral lubricating interfaces which exist between floating lateral bushings and gears in external gear machines (EGMs). The design of these lubricating gaps influences their ability to seal against leakages as well as reduce friction between solid components in the interface and thus, consequently affect the overall performance of the unit. Therefore, a comprehensive understanding of the performance of these interfaces is critical in achieving a reliable and efficient design of EGMs. However, to account for the complex phenomena in the gaps due to the coupled fluid structure interaction leading to an Elastohydrodynamic (EHD) lubrication regime, a high fidelity numerical model is needed.

Previous work in the authors’ research team had resulted in the development and experimental validation of a full fluid structure interaction (FSI)-EHD lubricating model for the lateral lubricating gaps, which remains the most advanced model for an EGM in the current state of the art. However, a very simplified and approximate approach to consider cavitating conditions in the lubricating gap is followed in this model, where the pressures are simply saturated to a constant minimum value during their solution whenever they cross a minimum threshold. This subsequently results in numerically unstable predictions of pressure when substantial cavitating regions are encountered while also violating mass conservation laws. To overcome this issue, this paper presents a stable mass conserving cavitation algorithm by implementing the universal Reynolds equation in the existing FSI-EHD model which is applicable for both full film and cavitating conditions and has been found to be applicable in several other tribological interfaces. Such a method offers to predict the onset and shape of the cavitating regions without the need for considering complex bubble dynamics. After outlining the formulation and implementation of the new cavitation algorithm, this paper also presents simulations of certain extreme operating conditions of a commercially available EGM, where using this cavitation algorithm was found to predict realistic pressure distributions in the lubricating interface while also maintaining the stability of such a complex lubricating gap model for EGMs.


11:45 8903 Xinran Zhao, Andrea Vacca and Sujan Dhar, Numerical Modeling of a Helical External Gear Pump with Continuous-Contact Gear Profile: A Comparison between a Lumped-Parameter and a 3D CFD Approach of Simulation

The concept of continuous-contact helical gear pumps (CCHGP) has been proposed and successfully commercialized in the recent past. Thanks to the continuous-contact rotor profile design and to the helical gear structure, this design eliminates the kinematic flow oscillation. This has important implications on the fluid borne noise generation, which is considered as one of the major sources of noise emissions and mechanical vibrations for positive displacement machines. Although the commercial success of the CCHGP concept, there is very little published studies about the underling physics at the basis of the functioning of this type of design. This is mostly due to the complexity of the fluid domain that characterize the functioning of CCHGP units. In this paper, a transient 3D CFD study is conducted for a reference CCHGP unit for high-pressure (up to 200 bar) fluid power applications. The results of the 3D CFD simulation are compared with those given by a lumped-parameter model developed at the Maha Fluid Power Research Center of Purdue University (USA), which was previously validated against experimental results. The results show how with a proper discretization of the fluid domain the CFD simulation approach can be used for the case of helical CCHGP units. Both models provide a good description of the main features of operation of the unit. The lumped parameter model is quicker, thus suitable for fast optimization studies. However, the CFD results not only can be used to support the main assumptions done on the lumped parameter model, they also permit to gain further insight on the operation of the CCHGP unit, particularly with respect to the flow features of the meshing process.


12:00 8928 Christian Schänzle, Nils Störmer and Peter F. Pelz, Modeling the Efficiency of Gear Pumps Based on Similarity Considerations

Gear pumps are used in numerous different applications and industrial sectors. However, when selecting a suitable gear pump for a specified application, manufacturers are often confronted with a lack of comparable measurement data for the desired combination of operating conditions and pumping fluid. Consequently, an estimation of the volume flow rate and the power consumption of a pump under the operating conditions of the application is necessary. In this context, this paper discusses the application of similarity on external gear pumps and presents its validation by means of measured pump characteristics. Seven gear pumps of different displacement volume are measured at different operating conditions varying pressure, rotational speed and the viscosity of the pumping fluid. The validation results prove that similarity is useful to represent a pump’s characteristic over a wide operating range. The prediction of the volume flow rate and the power consumption at a changed viscosity show good accuracy. However, the scaling of the pump characteristic based on the displacement volume show contradictory results.

Keywords: Efficient and intelligent systems, Fluid Power Systems

Session 11: Noise and Vibration


14:00 8809 Ryan Foss, Mengtang Li, Eric Barth, Kim Stelson and James D. Van de Ven, Addressing Valves with Pressure Ripple

Pressure ripple can be purposely used to transmit information within a hydraulic system. For example, introducing ripple at specific frequencies into a fluid line can activate a valve, eliminating electrical wires. A key element of this system is the hydraulic resonator that activates the valve when a specific frequency pressure ripple is present in the line. This paper presents a linear and nonlinear model of the hydraulic resonator with experimental validation. The hydraulic resonator consists of an inertance tube, a series capacitor, made up of a deforming elastic membrane, and an orifice. For system validation, displacement of a valve, the capacitor, and system pressure are measured.

Keywords: Components and systems, Fluid Power Systems, Modelling and Simulation

14:15 8855 Wieslaw Fiebig and Jakub Wrobel, System Approach in Vibration and Noise Investigation in Fluid Power Units

Many investigations show, that noise emitted by pumps depends on their mounting, i.e., the application and the layout of the piping system. The results show that the noise behavior of a pump is strongly system-dependent. The total sound power level is determined by the loudest source or sources of noise. Therefore, detection of the loudest noise sources in a power unit is very important. Successful noise reduction of hydraulic systems can only be achieved, when the design changes will be made to the loudest noise source or sources. Noise source location will be shown on example of a two fluid power units with horizontal and vertical situated motor pump group. Components of power units with larger radiating surfaces such as the electric motors and tank structure produce often the major part of the global noise radiation. Significant noise reduction in fluid power units has been achieved by reduction of vibration transmission from

the pump to the tank structure. The power unit is well optimized regarding the noise when its overall sound power level is close to the sound power level of the motor pump group. The Experimental Modal Analysis (EMA) on horizontal and vertical type fluid power unit has been carried out to identify the natural frequencies and mode shapes. To investigate the influence of rpm change on amplitude of vibration the Operational Vibration Analysis (OVA) has been carried out. Based on the results of acoustic and vibration measurements the FE- models of power units has been developed and FE- Modal Analysis of whole structure of fluid power units has been carried out. The results of FE- analysis show how to modify the structure of power unit to change the natural frequencies and to move these from the excitation frequencies of the pump. The sensitivity analysis has been carried out to investigate which parameters have the highest influence on natural frequencies of the power unit significant for the noise development. Finally the method for the noise reduction in fluid power units has

Keywords: Components and systems, Fluid Power Systems, Noise and vibration, System design

14:30 8828 Min Pan, Beichen Ding, Chenggang Yuan, Jun Zou and Huayong Yang, Novel Integrated Control of Fluid-borne Noise in Hydraulic Systems

The noise in hydraulic machines presents itself as fluid-borne noise (FBN), structure-borne noise (SBN) and air-borne noise (ABN). FBN is caused by the unsteady flow produced by pumps and motors or the operation of digital hydraulics, and propagates through the system causing SBN, which in turn causes ABN. This article reports on a novel integrated FBN attenuation approach, which employs a hybrid control system by integrating an active feedforward noise attenuator with passive tuned flexible hoses. The passive hoses are tuned to cancel the high-frequency pressure pulsations, whilst the active controller is designed to attenuate the dominant harmonic ripples. Adaptive notch filters with a variable step-size filtered-X Least Mean Square algorithm were applied in the new designed active piezoelectric actuator with high preload and operating forces, a wide bandwidth and very good linear dynamics. A time-domain hose model considering coupling of longitudinal wall and fluid waves was used to model and tune the flexible hose. Very good FBN cancellation was achieved by using the proposed integrated control approach, which was validated by comparing with numerical simulation and experiments. It can be concluded that the active attenuator with passive flexible hoses can form an effective, cost-efficient and practical solution for FBN attenuation. As the problem of high noise levels generated by hydraulically powered machines has risen significantly in awareness amongst industry and the general public, this work constitutes an important contribution to the sustainable development of low noise hydraulic fluid power machines.

Keywords: Fluid Power Systems, Modelling and Simulation, Noise and vibration

14:45 8899 Paul Kalbfleisch, Svenja Horn and Monika Ivantysynova, Cyclostationary Analysis of Measured Pump Acoustic and Vibration Signals

The stationary signal assumption is convenient as its signal processing methods are the minimum effort required to characterize periodic signals and therefore the most common. However, signals from rotating machines have been found to naturally be characterized as cyclostationary. The existent of natural phenomenon such as, shaft imbalances, turbulent fluid flows, friction, combustion forces, and torsional vibrations create modulation effects, that can be seen in the measured signals. These observed modulations in pump noise and vibration signals are synonymous to amplitude modulations (AM), frequency modulations (FM), and potentially phase modulations in electrical systems. Having this knowledge, the fluid power noise, vibration, and harshness (NVH) researchers can draw from an enormous amount of progress made in the modern telecommunication signal processing methods of cyclostationary signals. This article introduces the basic concepts of cyclostationary signals, some of their signal processing techniques, and a simple example of analysis for a positive displacement machine through the cyclostationary paradigm.

Keywords: Noise and vibration

15:00 8856 Wieslaw Fiebig, Jakub Wrobel and Piotr Cependa, Transmission of Fluid Borne Noise inside the Reservoir

In this paper the results from investigations regarding the transmission of fluid borne noise inside the reservoir structure has been investigated. In many power units there are vibrating elements submerged in the fluid like pumps, pipe elements, filters, etc. Due to the vibration of these elements fluid borne noise will be generated which will be transmitted to the tank structure. The transmission of fluid borne noise to the tank structure is dependent on its natural frequencies. FE model of the reservoir has been developed to analyse the natural frequencies. This model include the FSI (Fluid Structure Interactions) in which the influence of the fluid on the natural frequencies of the reservoir has been investigated. The natural frequencies of the empty reservoir are different from the natural frequencies of the reservoir filled with fluid. The results of Modal Analysis in term of natural frequencies and mode shapes of the reservoir have been compared. The transmission of the vibrations from the vibrating cylindrical body to the reservoir has been established experimentally on the physical model. The vibration of the cylinder submerged in the fluid in the cubic reservoir ware excited by the shaker. The vibrations amplitudes induced on the reservoir walls depend from the distance between the vibrating cylinder and reservoir walls. The results shows that the transmission of vibrations in the reservoir is lower in lower frequency range than in higher frequency range. This results confirm the results achieved by the noise sources

location in fluid power units in which the stronger noise radiation of the tank structure in the high frequency range has been observed.

Keywords: Modelling and Simulation, Noise and vibration

Session 12: Digital Displacement Pumps and Motors


16:00 8834 Noah Manring and Chris Williamson, Calculating the Mechanical and Volumetric Efficiencies for Check-Valve Type, Digital-Displacement Pumps

Check-valve type, digital-displacement pumps are among the most efficient pumps on the market, however, they have been known to undergo an apparent shrinkage in size with increased operating pressure. This phenomenon has made it difficult to describe the components of pump efficiency in terms of mechanical and volumetric efficiencies. In this paper, the shrinkage in pump size is described mathematically as a function of displacement command, operating pressure, stroke volume and residual fluid volume in a single piston chamber, and the fluid bulk modulus. In conclusion it is shown that the pump shrinkage calculation is necessary to avoid overestimating the mechanical efficiency, and underestimating the volumetric efficiency. The efficiency calculations presented are generally applicable to check valve or check ball pumps. The results are presented using experimental data collected by Danfoss Power Solutions for a 96 cc/rev Artemis pump.

Keywords: Digital and switched fluid power systems

16:15 8874 Niels Henrik Pedersen, Per Johansen and Torben Andersen, Four Quadrant Hybrid Control Oriented Dynamical System Model of Digital Displacement Units

Proper feedback control of dynamical systems requires models that enables stability analysis, from where control laws may be established. Development of control oriented models for digital displacement (DD) fluid power units is complicated by the non-smooth behavior, which is considered the core reason for the greatly simplified state of the art control strategies for these machines. The DD unit comprises numerous pressure chambers in a modular construction, such that the power throughput is determined by the sequence of activated pressure chambers. The dynamics of each pressure chamber is governed by non-linear differential equations, while the binary input (active or inactive) is updated discretely as function of the shaft angle. Simple dynamical approximations based on continuous or discrete system theory is often inaccurate and is not applicable for such system when it is to operate in all four quadrants. Therefore, a method of applying hybrid dynamical system theory, comprising both continuous and discrete elements is proposed in this paper. The paper presents a physical oriented hybrid model accurately describing the machine dynamics. Since development of stabilizing control laws for hybrid dynamical systems is a complicated task, a simpler hybrid model only including the fundamental machine characteristics is beneficial. Therefore, a discussion and several proposals are made on how a simpler DD hybrid model may be established and used for feedback control development.

Keywords: Control, Digital and switched fluid power systems, Drives, transmissions and actuators, Fluid Power Systems, Modelling and Simulation

16:30 8894 Matt Green, Jill Macpherson, Niall Caldwell and Win Rampen, DEXTER - The Application of a Digital Displacement Pump to a 16 Tonne Excavator

Environmental and economic factors are driving the development of lower emission and more fuel efficient off-highway vehicles. While a great deal of this development is focused on hybrid technology and novel system architectures, the simple application of a Digital Displacement® Pump (DDP) in place of a conventional pump can deliver significant fuel savings and productivity benefits, whilst also acting as an enabler for more radical future development. This paper describes the ‘DEXTER’ project, in which a tandem 96cc/rev DDP was installed in a 16 tonne excavator. The energy losses in the unmodified excavator are calculated based on test data, confirming the scope for efficiency improvements. Next, the basic operating principle and efficiency of the DDP and its application to the excavator system are outlined, alongside simulation based fuel saving predictions. The model based design and ‘operator in the loop’ testing of the control system are then described. Side by side testing of the modified excavator and a standard excavator showed that when the modified excavator was operating in ‘efficiency mode’ a fuel saving of up to 21% and productivity improvement of 10% is possible. In ‘productivity’ mode, a 28% productivity improvement was recorded along with a 10% fuel saving. These results are validated with reference to the higher efficiency of the DDP and improved control system which allows the engine to run closer to its torque limit.

Keywords: Components and systems, Digital and switched fluid power systems, Efficient and intelligent systems, Fluid Power Systems

16:45 8908 Sondre Nordås, Morten Kjeld Ebbesen and Torben Andersen, Analysis of Requirements for Valve Accuracy and Repeatability in High Efficiency Digital Displacement Motors

Traditional variable displacement piston machines achieve high efficiency when operating at high displacements, but struggle with poor efficiency at low displacements. The pistons are connected to high pressure and low pressure in conjunction with the output shaft position and the displacement is changed by changing the piston stroke, resulting in almost constant friction, leakage, and compressibility losses independent of displacement. In digital displacement machines, the rotary valve is replaced by two fast switching on/off valves connected to every cylinder. By controlling the fast switching on/off valves, the cylinders can be controlled individually and friction, leakage and compressibility losses can be minimized resulting in high efficiency even at low displacements. Previous studies have shown that high efficiency digital displacement machines require fast switching valves with high flow capacity and optimal valve timing strategy. When the digital displacement motor is to start, stop or be controlled at low speeds, the on/off valves must be able to open against high pressure difference. When opening the valves actively, the valve timing has to be conducted properly to minimize valve throttling losses and flow and pressure peaks. First, this paper shortly describes a previously developed method to estimate valve characteristics like transition time and flow capacity for a digital displacement machine. Then the paper presents a novel method of describing the required valve accuracy and repeatability to keep the valve throttling losses low and machine efficiency high.

Keywords: Digital and switched fluid power systems, Modelling and Simulation

17:00 8922 Niall Caldwell, Review of early work on Digital Displacement® Hydrostatic Transmission Systems

The paper describes work by the author between 1999 and 2006 for his Phd thesis “Digital Displacement Hydrostatic Transmission Systems”, in the context of earlier and later developments. Due to commercial confidentiality, the thesis has so far not been published - but will be in time for the conference. Before 1999, Rampen and collaborators at Artemis Intelligent Power Ltd. had demonstrated the first Digital Displacement pump (DDP) and pump/motor (DDPM), operating as a power-pack at constant shaft speed. This attracted the interest of Danfoss, who supported the author’s research to show feasibility of a mobile hydraulic product. The author built on Rampen’s work, coupling the DDP to an engine, and driving the wheels of a small vehicle with a DDPM capable of all four quadrants of operation. Experimental results are shown of the first complete Digital Displacement Transmission (DDT), featuring secondary control by DDPM displacement. The link between DDPM performance and the solenoid valve performance was identified. To enable increased motor speed range and volumetric capacity, valve transit speed and stability required improvement. Magnetic geometry was improved by parametric FEA, then time-domain behaviour was improved with a lumped-parameter model. Prototypes showed similar performance to that predicted. Embedded software was developed for control of the valves allowing variable–speed operation. The effect of discretisation of volume delivery on system characteristics was considered. System control software was developed to demonstrate the quality of motion, for both primary and secondary configurations. A time-domain simulation was created of the primary-controlled vehicle, which yielded good comparison to experimental results. The deterministic nature of the DDP lends itself to model-based system design methods, which have since been used to develop larger commercial systems such as forklift trucks, excavators and a 7MW offshore wind turbine. Following successful demonstration of the vehicle, Danfoss commissioned a 35cc/rev prototype, to demonstrate operation as a load-sensing pump in a full-scale aerial work platform. The author conducted the first detailed analysis of the energy loss and volumetric characteristics of this DDP, establishing the relationships between speed, pressure and displacement and the various loss sources. Informed by this, a semi-empirical loss model was developed and coefficients established for a 35cc/rev and later 11.8 cc/rev machine – the latter exhibiting a peak of 97% overall efficiency. Later work has confirmed that such favourable characteristics are maintained even at the megawatt scale, leading to a positive outlook to the commercial and environmental impact of this technology.

Keywords: Digital and switched fluid power systems

Session 13: Renewable Energy and Hybrid Vehicles

Friday 14th September 09:00 – 10:30

09:00 8853 Mikko Heikkilä, Mikko Huova, Jyrki Tammisto, Matti Linjama and Jussi Tervonen, Fuel Efficiency Optimization of a Baseline Wheel Loader and Its Hydraulic Hybrid Variants Using Dynamic Programming

In this paper, fuel consumption of a 5.7-ton municipal tractor in a wheel loader application is studied, and methods for improving the fuel efficiency are compared with each other. Experimental data from the baseline machine with load-sensing hydraulics has been gathered during a y-pattern cycle, and the data is inputted to an optimization function having realistic loss models for a hydraulic pump and diesel engine. Dynamic programming is used to analyze different system configurations in order to determine optimal control sequence for each system. Besides optimization of variable engine rotational speed on the baseline system during the working cycle (considering the point of operation), three hybrid supply

systems are studied: 1) a hydraulic flywheel, 2) parallel supply pumps and 3) a throttled accumulator. These systems utilize a hydraulic accumulator as an energy source/sink alongside the diesel engine. The optimal sequence for charging and discharging of the accumulator is examined in order to minimize the fuel consumption of the machine. The idea is to use the lowest acceptable, constant engine rotational speed, to cut down the diesel losses. In addition, the study covers an analysis of adjusting the engine rotational speed for each point of operation also when the hybrid systems are considered. The results show that finding advantageous engine rotational speed for each loading condition can decrease the fuel consumption of the baseline machine around 14%, whereas hybridization of the supply system can further improve the result by a couple of percentage units. Hybrid systems also reduce engine’s maximum load by making it more uniform, which allegedly reduces emissions. The possibility of engine downsizing to further improve the fuel efficiency of hybrid systems is not considered, because the maximum engine power is usually determined by the hydrostatic transmission of a municipal tractor. However, the study assumes that actuators are controlled using traditional 4/3 proportional control valves; hence, there are still potential for greater fuel savings. For example, applying independent metering valves on the actuator control can further decrease the system losses.

Keywords: Efficient and intelligent systems

09:15 8869 Mikko Huova, Jyrki Tammisto, Matti Linjama and Jussi Tervonen, Fuel efficiency analysis of selected hydraulic hybrids in a wheel loader application

There is a potential for significant improvement on fuel efficiency of many mobile machines by using hybrid technology as the Diesel engines are often driven at very inefficient operating points in these applications. The load generated by the working hydraulics of a mobile machine is often rapidly changing and contains high peak powers compared to the mean power required. This paper studies three different hydraulic hybrids in a wheel loader application. The study is based on a measured sand-loading Y-cycle. In addition to the hybrid systems, a load sensing proportional valve based reference machine and a modified machine based on independent metering valves are analyzed. All five system alternatives are analyzed systematically to enable a comparison of their fuel efficiency. The study shows that the fuel consumption of the machine can be decreased up to 28 % in such load cycle by using a suitable hydraulic hybrid system.

Keywords: Efficient and intelligent systems

09:30 8912 Qunya Wen, Feng Wang and Bing Xu, Modeling and design of a series hydraulic hybrid powertrain for compact wheel loaders

As an effective approach to improving the fuel economy of modern heavy-duty vehicles, hydraulic hybrids have shown great advantages in off-road vehicles. Wheel loader is one of the representative vehicles in off-road applications as they are usually designed for single and repetitive task such as loading material. In a typical short loading cycle, there are many accelerations and decelerations, showing great hybridization potentials. Therefore in this paper a series hydraulic hybrid powertrain has been proposed for compact wheel loader since its hydrostatic powertrain can be easily transformed to a series hydraulic hybrid with an additional hydraulic accumulator. The modeling and system design of the series hydraulic hybrid wheel loader have been presented. Three controllers have been designed for vehicle speed control, engine torque control and engine speed control respectively. A dynamic simulation model has been developed in MATLAB/Simulink. A rule-based energy management strategy (EMS) has been proposed for the series hydraulic hybrid wheel loader. Two different EMS schemes were investigated and compared through simulation studies.

Keywords: Modelling and Simulation, System design

09:45 8900 Biswaranjan Mohanty and Kim Stelson, High Fidelity Dynamic Modeling and Control of Power Regenerative Hydrostatic Wind Turbine Test Platform

Conventional wind turbines are equipped with multi-stage fixed-ratio gearboxes to transmit power from the low speed rotor to the high speed generator. Gearbox failure is a major issue causing high maintenance costs. With a superior power to weight ratio, a hydrostatic transmission (HST) is an ideal candidate for a wind turbine drivetrain. HST, a continuous variable transmission, has the advantage of delivering high power with a fast and accurate response. To evaluate the performance of the HST wind turbine, a power regenerative hydrostatic wind turbine test platform has been developed. A hydraulic power source is used to emulate the dynamics of the turbine rotor. The test platform is an effective tools to validate the control strategies of the HST wind turbine. This paper presents the high fidelity mathematical model of the test platform. The parameters of the dynamic equations are identified by the experiments. The steady state and transient operations results are compared with the experimental data. The detailed control architecture of the start-up and shut-down cycle is described for the test platform.

Keywords: Control, Modelling and Simulation, System design

10:00 8921 Haoxiang Zhang, Feng Wang and Bing Xu, Modeling and Experimental Study of a Novel Power Split Hydraulic Transmission

The characteristics of a novel power split hydraulic transmission are studied in this paper. The new hydraulic transmission is built from a balanced vane pump with a floating ring. By coupling the floating ring to the output shaft, it becomes a hydraulic transmission, converting the mechanical power on the input shaft into the hydraulic power at the

outlet and the mechanical power on the output shaft. By controlling the pressure at the outlet (control pressure), the power ratio transferred through mechanical and hydraulic path can be adjusted. One important feature of the new transmission is that the internal friction torque of the transmission, e.g., friction torque between vane tips and floating ring, helps to drive the output shaft whereas is wasted and turned into heat in a conventional vane pump. This increases the transfer efficiency from input shaft to output shaft. In this study, the characteristics of the input shaft torque, output shaft torque and the outlet flow rate are investigated through experimental studies. Results show that the shaft torques and the outlet flow rate are functions of control pressure and differential shaft speed. The mathematical models have been developed from the analytical and experimental results. The study provides a comprehensive understanding of the new transmission.

Keywords: Components and systems, Drives, transmissions and actuators

Session 14: Robotics and Prosthetics

Friday 14th September 11:00 – 12:30

11:00 8839 Janne Koivumaki, Wen-Hong Zhu and Jouni Mattila, Addressing Closed-Chain Dynamics for High-Precision Control of Hydraulic Cylinder Actuated Manipulators

Nonlinear model-based (NMB) control methods have been shown (both in theory and in practice) to provide the most advanced control performance for highly nonlinear hydraulic manipulators. In these methods, the inverse dynamics of a system are used to proactively generate the system actuation forces from the desired motion dynamics. To model the inverse dynamics in articulated systems, the Lagrange dynamics and the Newton-Euler dynamics are the most common methods.

In hydraulic cylinder actuated manipulators, a linear motion of the cylinder can be converted to a rotational joint motion between two links, creating closed-chain structures in the system. In Lagrange-dynamics-based control methods, the closed-chain structures are typically treated as an open-chain structure, which may raise the question of inaccurate system modeling. Contrary, the virtual decomposition control (VDC) approach is the first rigorous NMB control method to take full advantage of Newton-Euler dynamics, allowing to address the system nonlinear dynamics without imposing additional approximations.

In VDC, the actuated closed-chain structures can be virtually decomposed to open chain structures. To address the dynamics between the decomposed open chains, three specific terms (namely two load distribution factors and an internal force vector) need to be addressed. However, analytical solutions for these terms cannot be found in the literature. This paper provides the detailed solutions for these terms, which are further needed in a high-precision control of hydraulic robotic manipulators.

Keywords: Control, Fluid Power Systems, Modelling and Simulation

11:15 8842 Santeri Lampinen, Janne Koivumaki and Jouni Matilla, Bilateral Teleoperation of a Hydraulic Robotic Manipulator In Contact With Physical and Virtual Constraints

Teleoperated robotic manipulators can be used to remotely operate within hazardous, hard to reach or dangerous environments. In tasks requiring handling of heavy objects with high forces, hydraulic manipulators have remained the most practical solution. Contrary to the previous research on teleoperation of hydraulic manipulators based on linearization and linear control theory, the present study proposes a full-dynamics-based bilateral force-reflected teleoperation, designed between a multiple degrees-of-freedom (n-DOF) electrical master manipulator and an n-DOF hydraulic slave manipulator. The used teleoperation method allows arbitrary motion and force scaling between the n-DOF manipulators, effectively enabling the use of two greatly dissimilar manipulators. The proposed teleoperation system is demonstrated with a full-scale two-DOF hydraulic slave manipulator (having 475 kg payload attached to the tip) in a free-space motion task, and in a constrained motion task including both real and virtual constraints in the environment. Despite the inherent highly nonlinear dynamic behaviour of hydraulic systems and challenges in realizing a bilateral teleoperation, the experimental results demonstrate that the proposed controller for full-dynamics-based teleoperation 1) can rigorously address the system nonlinearities, 2) can realize a high-performance bilateral teleoperation with hydraulic slave manipulators, and 3) is capable to operate in constrained motion with the environment having both real and virtual (i.e., artificially rendered) constraints.

Keywords: Control, Fluid Power Systems

11:30 8846 Petri Mäkinen, Oleg Dmitrochenko and Jouni Mattila, Floating Frame of Reference Formulation for a Flexible Manipulator with Hydraulic Actuation - Modelling and Experimental Validation

One of the current and future trends in robotics is to reduce the weight of a robotic manipulator by using lightweight materials, such as ultra-high-strength steel or composites. The reduction in weight results in material and fuel savings, which are highly relevant for heavy-duty, off-highway manipulators found in excavators, truck-mounted cranes, and forestry machines. Due to the highly demanding working conditions of such manipulators, hydraulic actuation is mainly used. Automated and accurate control of these manipulators is very challenging due to the nonlinearities present in the system. Recent studies indicate that nonlinear model-based control (NMBC) methods can provide the most advanced control performance in the case of hydraulic robotic manipulators. An accurate model capturing the dynamics of the physical system is required for effective NMBC design. The present study proposes a hybrid rigid-flexible model for a flexible manipulator combined with a hydraulic actuator, implemented with the help of the floating frame of reference formulation (FFRF). The designed model is validated by comparing simulations with experimental reference data obtained from an OptiTrack motion-capture system and other sensors. The comparative results demonstrate that the model is able to capture the system's dynamics accurately, which motivates further research on developing NMBC methods using the FFRF.


11:45 8875 Rudolf Scheidl and Simon Mittlböck, A Hydraulic Piloting Concept of a Digital Cylinder Drive for Exoskeletons

The use of a digital cylinder drive for exoskeletons was proposed in the recent year as a means to save weight, installation space, and energy. Also the hydraulic actuation of the switching valves of the digital drive was brought into discussion, in particular by a so called hydraulic digital counter concept. That concept was originally invented to realize a digital hydraulic amplifier. It uses a mechanical input and feedback, transfers this into binary switching states of the valves which switch the chambers of the digital cylinder either to tank or system pressure. It is now reconsidered with a hydraulic input, a special design of the valves appropriate for the sub-kilowatts power ranges of exoskeletons, and a special control strategy. The configuration of this system with a true binary counting property requires the input pressure thresholds to grow exponentially with the number of binary stages of the drive. That limits the number of feasible stages to approximately five or six, complicates the mechanical parts of the valves which realize the hysteretic response to the pilot pressure, and increases the hydraulic power for valve actuation. To overcome these problems the system is configured as a quasi binary counter which jumps over certain digits if the input flow is monotonous, thus, requires a reversal of input flow to realize those digits. A theory and a numerical model of the counter in this configuration and a proper counting control strategy of the hydraulic input are presented. With this much higher number of digits can be realized and valve design and configuration are eased.

Keywords: Control, Digital and switched fluid power systems

12:00 8891 Mikko Huova, Matti Linjama, Lauri Siivonen, Till Deubel, Heino Försterling and Edgar Stamm, Novel Fine Positioning Method for Hydraulic Drives Utilizing On/Off-Valves

This paper studies a novel on/off-valve-based fine positioning method for hydraulic drives. The method proposed utilizes four on/off-valves in independent metering configuration to reach good positioning accuracy and low power losses. Previously, servo valves have been used in precise position control of hydraulic double acting cylinders. Another approach uses on/off-valves, which are typically driven by using pulse width modulation (PWM) or, if there are parallel connected valves, pulse code modulation (PCM). Typically, both cylinder sides are modulated simultaneously. The new concept proposed uses a cylinder model to calculate a correct opening sequence for the on/off-valves, such that the target piston position is reached. The method proposed modulates single cylinder side at a time in order to achieve small piston position step sizes. Despite relying on the modelled compressibility of the fluid, the method presented requires no knowledge about the bulk modulus of the fluid. It is enough that the bulk modulus of the fluid in both cylinder chambers can be assumed equal. The paper includes the design of the control method, a simulation study proving the validity of the method and an experimental part investigating the performance in practice. The experimental results show a positioning accuracy of +/- 1 μm with an on/off-valve-based hydraulic drive, the maximum velocity of which is 0.7 m/s.

Keywords: Control, Digital and switched fluid power systems

Map of Campus

From http://www.bath.ac.uk/publications/claverton-down-campus-flat-map/

See also http://www.bath.ac.uk/topics/travel-advice/

Lime Tree

Restaurant

Chancellors’ Building (for technical sessions)

Coach pick-up

http://www.bath.ac.uk/publications/claverton-down-campus-flat-map/

http://www.bath.ac.uk/topics/travel-advice/

Map of Bath, showing venues for receptions

Holburne Museum (Wednesday)

Assembly Rooms

(Thursday)

bath/asme symposium on fluid power and motion control · 16:45 8917 andrea de martin, andrea...

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