a grinding machine controller with enhanced process monitoring integration john moruzzi geri /...

A grinding machine controller with enhanced process monitoring integration

John MoruzziGERI / AMTReL


M. N. Morgan, X. Chen, D.R. Allanson


AMTReL 1300X Grinding Machine

• Universal grinding machine• External and Internal wheelheads• SAMM control (Servo Assisted Manual Machine)• Prototype machine based on Format 15 model• Built circa 1994, modified 2001• Closed control system – Industrial PC / MS-DOS

LJMU: M/C and Initial Control Arrangement

Aims of the project

The objectives are to:

•Replace old ‘closed’ CNC control – new PC hardware•New simplified operator panel•Touch screen operation•Implement existing cycles for External grinding•Enhance cycle programming and machine setup•Interface and integrate external process control equipment•Demonstrate optimised cycle

•Modern software design and implementation•Expandable for intelligent and adaptive grinding features

A Low-Cost, Expandable, Open-Architecture Grinding Machine Control System

New System Components


Control system modifications:

•Industrial rack PC •Workhead servo drive•Motion control card•Touchscreen monitor•Console switches / lamps•Cabling / connectors•Process control unit

Quality, Efficiency and Safety Issues


Quality Issues Efficiency Issues Safety IssuesSize tolerance Air grinding time before machining Wheel collision

Surface roughness Dwell time after machining Wheel failure

Roundness Incorrect wheel dressing intervals Wheel overspeed

Burning Material removal during dressing

Spindle wear Damaged dressing tool

In practice the physical variability of the grinding process, such as wheel wear, machine deflections, wheel vibrations and temperature variations mean that adjustments to the grinding parameters need to be made in order to improve the quality of the finished part .

Auxiliary process monitoring equipment will help operators and machine controls to identify, optimise and correct key machining issues.

Improving the grinding process


In machining, and particularly grinding, it is desirable to have a control system that can integrate and adopt the latest Process Control and Monitoring equipment, and implement enhanced production cycles.

Grinding optimization technologies include wheel balancing, in-process gauging, touch detection (power and acoustic emission) and other sensor-based strategies.

A selection of such features may be included in higher-end grinding machines in response to specific requirements, however this involves significant customisation and application engineering from the machine builder.

It has proved to be impractical or uneconomic to apply the benefits of this technology to simpler, cheaper grinding machines, despite the fact that low-cost process control equipment is becoming increasingly available.

Monitoring of the grinding process


As various programmed conditions are met during machining, appropriate signals and visual indications are set by the device. The operator or machine control will then respond to this information according to a defined strategy.

Auxiliary Process Monitoring equipment is generally a stand-alone unit, connected to the machine control via a wiring or communications interface. The operator will set the device operating parameters and monitor its behaviour via a control panel.

Key monitoring and control features are:

• Wheel Balancing (vibration sensing / correction)• Touch Detection (Acoustic Emission or Power sensing)• Gauging (Size / Position measurement)

The enhanced system design implements a simpler integration of process monitoring equipment with the machine control system.

Main equipment suppliers


• Lack of standardisation between CNC and equipment manufacturers• Different interfacing hardware and strategies for Process Control equipment. • Different levels of functionality / complexity

CNC

Fanuc

Mitsubishi

Siemens

Heidenhain

Fagor

Num

OEM / Custom

….

Gauge

Marposs

Movomatic

Balance Systems

Control Gauging

Touch

Dittel

Movomatic

Balance Systems

Marposs

Balance

Balance Systems

Schmitt

Dittel

Marposs

MPM

Elaso

Challenges leading to the development of a generic type interface:


Key Control System Elements

The main features of a machine tool control system are:

Operator HMI panel

Operator input and control

features

Axis control and position

measurement

Additional measurement

and control equipment

Computer processing unit with setup and

program storageOperator

program and status display

featuresMachine <=> Control

signal interfacing

Many of these elements can be treated as interconnected devices or packages that compose the complete system.

Interfacing of System Equipment


System devices are interconnected to transmit and exchange:

• Control signals• Status signals• Process data• Configuration data

N.B. There is a wide variety of communications and signalling hardware and protocols.

CNC IO modules

CNC main module

Process Monitoring unit

PC unit

RS232

Digital IO

Ethernet

ProfibusDigital IO

Bus

Bus

CNC axis drives

Digital IO

Bus

Analog

Ethernet

New Control Objectives and Innovation


An innovative new software design strategy has been designed to directly address the issue of improved process control integration.

The aim is to unify the design and implementation of key machine tool features such as hardware configuration parameters, operational parameters, process variables and machining cycles into a rationalized, extendable, Object-Oriented framework suitable for implementation using current PC hardware and software.

In order to implement such a framework it is necessary to identify and specify the key features and requirements of the new system:

The main items for consideration are:• Cycles and Part programs (Grinding, Dressing, Balancing)• Hardware features (Connectors,Interfaces)• Communication features (Protocols, data structures)• Operational features (Functions, signals, data)• Software features (Configuration, displays)

Open Control Systems: the idea

• Commercial or Industry standard hardware (increasingly moving in this direction)

• Modular software structures (now common practice)

• Well defined software interfaces - standardised

• Vendor-neutral architectures and application modules

• Flexible and reconfigurable , adaptable to new technologies and processes

• Layered approach to structure hides hardware-specific features


The new system builds on the Open Control Systems concept, originating in the 1990s for Machine Tool Control applications:

Key interactions with Devices


Main actions :

• Device configuration

• Device operation

• Device monitoring

Main data:

• Control, status and alarm signals

• Process signal values

• Device parameters

What we need our control system to do…

John Moruzzi:Open Device Interface (ODI) framework

Level 5 : User program (application)

Level 0 = Low level (hardware) API libraries

4 levels of OPI Software Classes / Objects:

Level 4 : Application Object LayerObject Instances: Actual data items e.g. actual devices (e.g. MyGauge)

Level 3 : Data Presentation LayerDerived Classes: More specialised device class (e.g. VM9TD)

Level 2 : Session Management Layer Base Classes: Basic definitions to be enhanced (e.g. TDevice TParam)

Level 1 : Data Transport LayerAPI routines: Libraries for access to specific hardware (e.g RS232)

A newly proposed Object-Oriented design that enables the structuring of Device software classes (Base and Derived) to provide a standardised top-level programming interface with abstracted levels of specific functionality at the lower levels.


Example ODI device implementation


Level 4:Application Object

Object Instances

Level 3:Data Presentation

Derived Classes

Level 2:Session Management

Base classes

Level 1:Data Transport

API routines

TouchDetectorUnit_1 TVM9_TD_Device TDevice

TouchDetectorUnit_2 TVM20_TD_Device

GaugeUnit TVM9_GA_Device

BalancerUnit TVM9_BA_Device

TDIOInterface TInterface

DigitalIO(1) TDV004_DIO_Device Deva.get_digital_inputw

DigitalIO(2) TBB48D_DIO_Device BB.write_output_port(B)

VM9Unit.Serial TSerial_Interface Win.Com1.Output = ..VM20Unit.Profibus TProfibus_Interface DevInitBoard()

TouchCycle1.Active TSignalState TProcessSignal

AE.Channel(1).Value TDataValue TProcessData

AE.Channel(1).Gain TParameterValue

GapCycle.State TGapElim_Cycle TProcessCycle

GaugeCycle2.State TGauge_Cycle

AutoBalanceCycle.State TAutoBalance_Cycle

This diagram indicates the levels of Abstraction and Inheritance in Classes using the Object-Oriented Approach :


Example Device Class : BS VM20–TD

Config Data (Acyclic)Report device details

Command data (Cyclic)Turn features On /Off etc

Status data (Cyclic)Reporting of device events

Monitor Data (Cyclic)Live device signal values

Parameter Data (Acyclic)Read / Write setup info

Signal Data (Cyclic)Digital Inputs / Outputs

Key data structures and operations of a typical device:


VM20 TD – Parameter & Config data

Parameter Data :

Device <=> ControlConfig Parameters(Gain,Filter,…)

Working Parameters(Limits,…)

Parameter Item:Device <=> Control Accessed from Address on Page in Device memory.

Command sent to Request or Update parameter data


VM20 TD – Monitor & Control data

Monitor Data :Device => Control

Process data valuesSelectable content: AE1 & AE2 AE1 & PWR1 …….

Control Data :Control => Device

Activate featuresSelect programStart / Reset Cycle

Summary of studied ODI devices


Devices implemented:

Jones & Shipman 1300X Operator Panel (RS232)Balance Systems VM9TD Touch Detector Unit (RS232)Balance Systems VM20SYS System Rack (Profibus)Balance Systems VM20BA Balancer Card (Profibus)Balance Systems VM20TD Touch Detector Card (Profibus)Balance Systems VM20GA Gauge Card (Profibus)

Devices studied:

Deva004 Motion Control (Digital IO)Fanuc CNC CNC Interface (Ethernet / FWLIB)

Heatmiser UH1 Building Heating Control (RS485 / TCPIP)

Applications of the ODI Library


Overall software and hardware structure:(and its uses beyond this application)

ODI Device Library

TDeva_004TVM9_TDTVM9_BA

TVM20_TDTDTLM5000_BA

…..T1300X_Panel

THM_UH1Control

BS VM9BA

BS VM9TD

BS VM20SYSBS VM20BABS VM20TD

Dittel M5000 MA

J&S 1300X Panel

Dittel AE4000

CNC Program(Machine control)

e.g. J&S 1300X

Monitor Program

IGAIGPS

HeatMiser UH1

Deva 004

User Application Virtual Device Actual Device

The IGA application example


The IGA (Intelligent Grinding Assistant) was developed previously at AMTReL as an external PC program that interfaced between the Fanuc CNC of the Jones & Shipman Ultramat grinder and its installed VM20 Balancer, Touch Detection and Gauging Unit.

It was able to demonstrate Adaptive Control of the grinding cycle parameters, by monitoring live process data values (e.g. spindle power, wheel acoustic emission) at various points in the cycle, and performing analysis and calculations on the data.

Quantities such as the system Time Constant τ can be calculated from the power signal (least mean squares method) during the initial contact or dwell phases of the grinding cycle.

The Time Constant can be used to adapt the wheel infeed rate parameter or the sparkout dwell time parameter.

IGA implementation with ODI


IGA ProgramBS VM20SYSBS VM20BABS VM20TDBS VM20GA

J&S Fanuc CNC

EthernetLink

ProfibusLink

Cycle parametersCycle phaseCycle commands Balancer Data

Touch / Power dataGauge data

Config parametersSystem Status data

Programmed cycle parametersOptimised cycle parameters

Time Constant ModelBurn Model

Grinding Database

ODI device libraryUltramat Machine

The existing IGA program was studied and adapted to work with the ODI implementation of the external system devices.

Summary


• A revised and modernised Control System package for a grinding machine has been specified, designed and developed.

• An Open Device Interface (ODI) to facilitate the integration of various Grinding process Control and Monitoring devices has been designed and demonstrated.

• The Object Oriented Framework allows a common access strategy for different makes and models of equipment (a generalised Device Object) by using layers of hardware and software abstraction.

• Application software can now interact with different Devices much more easily, and Harmonised user interface allows the operator to work with different devices easily.

• Different communications methods between devices are supported

• The concept is extendable for the control of other Device types such as Motion / Axis Controllers or even Building heating controllers.

End of Presentation

Any Questions ???


Thank you for your attention.....

a grinding machine controller with enhanced process monitoring integration john moruzzi geri /...

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