8/7/2019 HyperWorks for Multi-Body Dynamics in the Design & Development of a Novel Suspension System

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ChallengeULTra ® is a revolutionary form of Personal Rapid Transit (PRT). The ULTra ® system uses a fleet

of low power, electrically driven vehicles on a dedicated guideway. Once on the guideway,

each vehicle becomes autonomous, adjusting steering and speed where necessary using a

combination of sensors embedded in the track and on the vehicle.

One of the project tasks that ARRK R&D undertook was to design and study the suspension

system of the ULTra ® vehicle fleet. The vehicle has four passenger seats, accommodating a

combined occupant and luggage payload of up to 500kg and travels at speeds up to 40 kph

(25mph). It has a small (5m) turning radius and copes with gradients of up to 20%.

HyperWorks for Multi-Body Dynamics in the Design

& Development of a Novel Suspension System

HyperWorks is a division of

Case Study

OverviewARRK Research & Development Limited was tasked by Advanced Transport Systems (ATS) toengineer, prototype, test and manufacture ULTra ®; a driverless, battery powered vehicle for theworld’s first Personal Rapid Transport (PRT) system at Heathrow Airport Terminal 5. The ULTra ® suspension system was designed and developed using a number of multi-body dynamics(MBD) modelling techniques in conjunction with an independent (parametric) whole vehiclehandling simulation.

HyperWorks’ MotionSolve, HyperView and HyperStudy were used (in tandem with CarSim) todevelop the suspension geometric properties to meet specific cascaded targets, to reducevehicle weight, to predict forces under a variety of loads and to estimate response to trackinputs.

Business Profle

ARRK Research & Development Limited is a design, engineering and recruitment consultancy

providing managed solutions throughout the complete product development process with

offices in Basildon and Coventry, UK. ARRK’s customers come from a wide range of industries

including transportation, aerospace, energy and consumer goods. ARRK R&D are members of

the ARRK Global Network which employ over 22,000 people within 120 companies worldwideenabling them to provide customers with comprehensive product development services.

Fig. 1: ULTra ® Prototype

www.altairhyperworks.co.uk

“HyperWorks allowed us

to reduce our overall design

time while minimising the

mass of the vehicle and

optimising components

for ideal performance

characteristics.”

David Fothergill ARRK R&D

8/7/2019 HyperWorks for Multi-Body Dynamics in the Design & Development of a Novel Suspension System

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Altair Engineering Ltd Imperial House, Holly Walk, Royal Leamington Spa, CV32 4JG, UKPhone: 01926 468 600 • Fax: 01926 468 601 • www.uk.altair.com • info@uk.altair.com

Solution

The project required the implementation of mechanical analysis to fulfill the design anddurability requirements, as well as the study of the variation of loading weight during

operational cycles.

The project used a technical approach commonly known as ‘Target Cascading’. This method

consists of establishing the requirements of the design using a high level parametric vehicle

model, then ‘Cascading’ these requirements to the (vehicle suspension and steering)

subsystem level as a set of targets, which are then used as objectives in the design and

optimisation of the subsystems. The resultant elasto-kinematic properties of optimised

candidate subsystem designs are then passed back to the parametric model in order to

predict the vehicle performance.

The ‘Cascading’ approach was successfully used to study the steering response during all

loading conditions and the level of ride comfort when the vehicle travelled over the guideway

joints. HyperStudy was used extensively to optimise the sub-system parameters. A full

MotionView multi-body dynamics (MBD) vehicle model was used to calculate operating loads.

Quasi-static and dynamic loading was modelled in order to target durability requirements.

In terms of passenger weight and its influence during loading, travelling and alighting,

the MBD vehicle model was employed to explore the system stability and its potential for

measuring payload with reasonable accuracy.

Fig. 2: Parametric Model withSubsystem characteristics

Fig. 3: Typical Dynamic Force Responseto Traversing a 32mm Obstacle

ResultsMotionSolve proved to be a very robust tool to solve the complex multi degree-of-freedom

systems required to represent a whole vehicle. HyperStudy was employed to optimise steering

geometries and it proved to be a simple way of optimising complex mechanical systems. In

addition, the report wizard in HyperView was a very efficient tool for repeat plotting activities

allowing for a reduction of time in order to obtain customised and optimum results.

The HyperWorks suite allowed ARRK R&D to reduce their overall design time through the

use of the integrated toolset. The software helped ARRK R&D to deliver the project on time,

while reducing the mass of the vehicle and optimising components for ideal performance

characteristics.

Fig. 4: Whole Vehicle MBD Model with Track Obstacle

Altair HyperWorks

Modeling and Assembly

Robust DesignOptimization

Design AnalysisVisualization

Reporting Virtual Manufacturing Process AutomationData Management

For more information please visitwww.altairhyperworks.co.uk