a low-cost, expandable, open- architecture grinding machine control system john moruzzi amtrel a...

A LOW-COST, EXPANDABLE, OPEN-ARCHITECTURE GRINDING MACHINE CONTROL

SYSTEM

John MoruzziAMTReL

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

Director of Studies: Dr Michael Morgan

AMTReL Jones & Shipman 1300X

• 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


Used for previous AMTReL projects/PhD’s

Adaptive control (Y Chen)Open CNC Interface (C Statham)

High speed Internal grindingIndustry co-operations (Timken, Lucas, …)Fluid delivery methods, nozzle designAE monitoring Dressing tool control (fluid coupling)

Aims of the project

• Replace old ‘closed’ CNC control• 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


Initial Objectives

MachineFamiliarity with machine & electrics

Re-commission hardwareMove axesReplace workhead drive

Modifications to wiringDisable hardware limits

Remove original control panel

Control systemInitial “desktop” PC control :

ISA bus motion control cardNo Digital I/O cardStandard mouse / keyboard / monitor

Initial SoftwareWindows 2000 (XP), Visual BasicProgramming familiarityAxis configuration (Utility S/W)Axis movements (Utility S/W, libraries)Simple grinding cyclesSimple cycle parametersNo I/O features


Phase 2 Objectives

MachineModifications to hardwareOptimise axes (drives)Replace original digital I/O wiring

Activation of workheadexternal wheelcoolant pump

Modifications to wiringEnable hardware limits

Interface to original control panelInterface external control devices (Power, AE)

Implement new control panel

Control systemNew “industrial” PC control :

Rack mount case with Mini-ITX PC boardPCI bus motion control cardDigital I/O from motion cardStandard mouse / keyboard / monitorLCD / Touchscreen monitor

Developed softwareWindows XP, Visual Basic / .NETProgram design & implementationParameter definition & managementEnhanced axis moves (MPG)Standard grinding cyclesEnhanced cycle programmingInitial IO featuresRS232 connectivity


Architecture of a CNC system

Main Control

Executor Scheduling, program execution, monitoring

IO routines HMI, programming, Digital, Bus

Safety Machine logic

Cycle management Sequencing, monitoring

Motion Control Axis movements, motors

Process optimisation

In-process Gauging Diameter, Shoulder

Touch Detection AE, PowerWheel balancing Auto / ManualProbing

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

Adaptive / Intelligent Control

Adaptive strategy Parameter modificationSelection strategy Rule / Case basedProcess models & rules Kinematic, ComplianceDatabase Learning strategy, data

New Components

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


Grinding Wheel speed and Control

WheelspeedRotational speed ns (RPM) Surface speed vs (m/sec)

Fixed on 1300X machine , can be changed with gearing / pulleys (3 ratios)

Control buttons: SB4 Start Wheel GreenSB3 Stop Wheel Red

Control relays: KA5 Wheelhead Stop OverrideKA12 Enable Internal WheelheadKA13 Enable External Wheelhead


Workhead speed and control

WorkspeedRotational speed nw (RPM) Surface speed vw (m/sec)

Variable on most grinding machines Controlled by operator / programOpen-loop motor drive control 3rd axis on motion cardCalibration Reference Voltage => speed


Control buttons: W+ W- Speed Down / UpSB8 Start Workhead GreenSB7 Stop Workhead Red

Control relays: KA4 Workhead Stop OverrideKA6 Workhead Start OverrideKA7 Workhead Stop Relay

Deva 004 : Axis servo setup

Z axis parameters

PITCH = -10.0000 MAXVOLT = 3000 (2150)COUNT = 10000.0000 MAXSPEED = 60

MAXACCEL = 60GAIN KV = 15

SPEED = 25


Motion card driver : Set up and adjust axis configuration parameters in, to match to real-world values and give satisfactory response characteristics.

Optimization / minimization of lag and overshoot

Also :Adjust servo drive amplifier settings, to give satisfactory response characteristics. Tuning of amplifier trim-potsOptimization / minimization of drift and overshoot

Axor MTS 400

VEL Fine speed adjustment Offset Zero volt drift compensationkV Dynamic response (gain)Der Derivative gain

Workhead drive setup #1


Original drive unit (with choke)

Original transformer (single phase)

• Non-standard drive and transformer (undocumented, unsupported)• Non-functioning

Workhead drive setup #2


New servo drive unit New transformer(3 phase 2kW)

• Axor drive Masterspeed MTS-200-14/28 and transformer TT2000/200-300 • Matched to wheelhead motor SEM MT40-P4 • Equivalent to Control Techniques Maxi-Maestro DCD 200 25/50

A

wheel power monitor

Motion Control Interfacing

Problem : to integrate a new Motion card with the existing machine wiring.

Original ISA bus Motion card – 4 axes on 2 boards:Conn 1 15W D Axis 0 encoder inputsConn 2 15W D Axis 1 encoder inputsConn 3 9W D Axis 0 , 1 servo outputsConn 4 15W D Axis 3 encoder inputs Conn 5 15W D Axis 4 encoder inputsConn 6 9W D Axis 2 , 3 servo outputs

New PCI bus Motion card – 4 axes on 1 board + flyer cables:

Conn 1 15W D Axis 0 encoder inputs / limit signalsConn 2 15W D Axis 1 encoder inputs / limit signalsConn 3 15W D Axis 2 encoder inputs / limit signalsConn 4 15W D Axis 3 encoder inputs / limit signalsIO2 25W D Axis 0, 1, 2 , 3 servo outputs


Digital I/O Interfacing

Problem: To integrate a new Digital IO card with the existing machine.

Original ISA bus I/O card – 48 opto-isolated signals on 50W D connector:Conn 1 50W D 24 inputs, 24 Outputs, 2 x common

New PCI bus Motion card – 48 opto-isolated signals on 2 flyer cables:IO1 25W D 12 inputs, 9 Outputs, 2 x common, 1 x WDog IO2 25W D 4 inputs, 3 Outputs, 2 x common

Machine requirements: 16 Inputs, 7 Outputs, 1 x WDog

Connection: To terminal rails in electrical cabinetTo auxiliary control equipment


Signal Interface Unit

To convert one set of signal configurations to be compatible with the machine wiring


Servo 0, 1, 2, 3

MachineInterfaceControl PC

Servo 0 , 1

Servo 2 , 3

Outputs 0..11

Encoder 0

IO1 Inputs, Outputs

IO2 Inputs, Outputs

Encoder 1

Encoder 2

Encoder 3

Inputs 0..15

Encoder 0

Encoder 1

Encoder 2

Encoder 3

AdditionalAdditional

Signal Interface Unit cont...

Implemented as 2U high 19” rack enclosure


Rack assembly with connecting cables

Electrical cabinet :- I/O


I/O terminals

Fuses

Relay board

Control PC hardware

IEI Kino 945 GSE• Industrial Mini ITX board with Intel Atom

1.6GHz CPU (Fanless)• 1 x PCI expansion slot• 1 x 200pin DDR2 SODIMM slot• 2 x SATA connectors, 1 x IDE• 2 x RS232 ports on rear I/O • 1 x RS232 port (internal)• 1 x RS232/422/485 port (internal)• 8-bit digital I/O

Further equipment• 2U 19” rack PC case with PSU• Operating system Windows XP

• 8.4” LCD Touchscreen (VGA, RS232)

• Deva 004 Motion card (4 axis + I/O)

• 2U 19” rack for signal interfacing• Blank 19” rack panels

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

Control PC hardware cont...

Front of 19” control console:• VM20 unit 3U (balance / touch)• Blank panel 1U• PC rack unit 2U• Signal Interface unit 2U

Inside of control console:• Axis cabling• I/O cabling• Cross connections

An Introduction to Grinding Machine Control Systems

Software panel – main screen

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

Main user interface

Z axis status and Jog

X axis status and Jog

Manual axis control

Cycle start / stop and status

Grinding mode and program control

Machine functions control

Software panel – program screen


Cycle programming - Traverse

Common grinding cycles

Dressing Single point “diamond” dressing:Wheel rotating (surface speed vc )Wheel traverses past diamond tip (crossfeed velocity vf)

Wheel infeeds an increment (infeed amount ad)Repeat until wheel surface fully dressed

Plunge grinding Workpiece / table positioned relative to wheelWheel and workpiece rotating (vc and vw)Wheel infeed at Rapid speed to start position (dia)Wheel infeed at Coarse feed to Fine Feed start position (dia)Wheel infeed at Fine feed to Final Size position (dia)Sparkout or Dwell with no infeed

Traverse grinding Workpiece / table set to oscillate across wheelWheel and workpiece rotating (vc and vw)Wheel infeed at Rapid speed to start position (dia)Wheel infeed by Coarse increments to Fine Feed start position (dia)Wheel infeed at Fine feed to Final Size position (dia)Sparkout passes of wheel with no infeed


Automatic Plunge Cycle


Cycle parametersPlungeCoarseInfeed As DoublePlungeFineInfeed As DoublePlungeFineDia As DoublePlungeStartDia As DoublePlungeSizeDia As DoublePlungeDwell As Double

Motion parametersdblXMovespeed As Double dblXRapid As Double dblXCoarseFeed As DoubledblXFineFeed As DoubledblXInfeed As DoubledblXInfeedRate As DoubleintXDwell as Integer

dblXStartPosition As DoubledblXFinePosition As DoubledblXSizePosition As Double

dblZReversePositionL As DoubledblZReversePositionR As DoubledblZStartPosition As Double

intFROSetting As IntegerblnFeedHold As Boolean

Cycle State Machine

Auxiliary variablesWheelSpeed As DoubleWorkSpeed As DoubleWheelheadOn As BooleanWorkheadOn As BooleanCoolantOn As Boolean

Interfacing of Peripherals 1


RS232:Com 1,9600 Baud, No Parity

Connect to 1300X Operator Panelvia RS232:

Read Data String: FRO value, button values, checksum

Write Data String:Axis position displays, Workspeed display, LED values, checksum

Interfacing of Peripherals 2


RS232:Com 2,38400 Baud, No Parity

Connect to Balance Systems VM9 TDvia RS232:

Read Data String: Signal values, Parameter values, checksum

Write Data String:Operating commands, Parameter settings, checksum

Object Oriented Design

• OOD (Object Oriented Design) models software as people would describe the objects in the world.– OOD takes advantage of class relationships where objects of a certain

class (e.g. a class of Vehicle) have the same characteristics. (e.g. a Car, a Truck, a Bus).

– OOD also takes advantage of inheritance relationships where a new class of objects is derived by absorbing characteristics of an existing class of objects and adding unique characteristics of its own.

• An object of class Convertible has the characteristics of class Car, but additionally, has a convertible roof.


Introducing OO . . . cont

• An Object has attributes . . .– i.e. size, shape, colour & weight.

• . . . and exhibits behaviours.– i.e. a ball rolls, bounces, inflates & deflates.

• A Class has Properties . . . – that describe its state and features

• . . . and Methods – that allow it to perform and experience actions


OO Class example

A fundamental object could be of type Parameter, with various Attributes and Operations (i.e. Properties and Methods)

Class: Parameter Derived classes: CycleParameterAxisParameterVM9 Parameter

….Properties: Data Type Methods: ReadValue

Decimal places WriteValueGroup FormatValueLevel ResetValueValue GetAddressMin Value ….Max Value

….


Some System Parameters


Axis ConfigurationXAxisChannel As AxisParameterXAxisPitch As AxisParameterXAxisCount As AxisParameterXAxisKV As AxisParameterXAxisMaxSpeed As AxisParameterXAxisMaxVolt As AxisParameter

Traverse CycleXCoarseInc As CycleParameterXFineInc As CycleParameterTraverseZFeed As CycleParameterTraverseStartDia As CycleParameterTraverseFineDia As CycleParameterTraverseSizeDia As CycleParameterZ0Dwell As CycleParameterZRevDwell As CycleParameterTraversePasses As CycleParameter

VM20 Balancer FunctionMinimumTolerance As BalanceParameterMaximumTolerance As BalanceParameterMaximumUnbalance As BalanceParameterNominalSpeed As BalanceParameterUnbalanceMeasuringUnit As BalanceParameterBalancingCycleTimeout As BalanceParameterCollectorType As BalanceParameterBalancingHeadType As BalanceParameterOptionRPMOutput As BalanceParameter

RS232 ConfigurationPort As RS232ParameterBaudrate As RS232ParameterParityChecking As RS232ParameterHandshaking As RS232ParameterInBufferSize As RS232ParameterOutBufferSize As RS232Parameter

UML Class Diagram

. . . ?Universal Modelling Language

The UML Class diagram allows us to model the classes in the system and their relationships.

Class diagrams :

• model a class as a rectangle.

• The top zone displays the class name.

• The middle zone contains the class attributes.

• The bottom zone contains the class operations.


Progress

So far.....

Reactivation of machine toolElectrical modifications, new workhead drive

Initial software with old hardwareDevelopment software with new hardware

Axis configuration and movementFamiliarity with motion control package

Implementation of simple cycles

Design and build of control unit, IO conversion

Developed basic interface design

Communication with external equipment

Next steps....

Formal definition of software structure

Integration of TouchscreenConnection with VM20 unit (RS232/Profibus)

Axis movement via MPGs: Improved driver


Issues....

Machine removed for workshop rebuild since August 2011

New workshop with machines availableduring April 2012 ?????

VM9 Touch Detector unit with Hydrophone ?

And finally...

Any Questions ???


Thank you for your attention.....

a low-cost, expandable, open- architecture grinding machine control system john moruzzi amtrel a...

Documents

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motion control axis

ratios control buttons

external grinding

expandable openarchitecture

adaptive grinding

isa bus motion control

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