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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
A Low-Cost, Expandable, Open-Architecture Grinding Machine Control System
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
A Low-Cost, Expandable, Open-Architecture Grinding Machine Control System
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
A Low-Cost, Expandable, Open-Architecture Grinding Machine Control System
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
A Low-Cost, Expandable, Open-Architecture Grinding Machine Control System
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
A Low-Cost, Expandable, Open-Architecture Grinding Machine Control System
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
A Low-Cost, Expandable, Open-Architecture Grinding Machine Control System
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
A Low-Cost, Expandable, Open-Architecture Grinding Machine Control System
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
A Low-Cost, Expandable Open-Architecture Grinding Machine Control System
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
A Low-Cost, Expandable, Open-Architecture Grinding Machine Control System
Original drive unit (with choke)
Original transformer (single phase)
• Non-standard drive and transformer (undocumented, unsupported)• Non-functioning
Workhead drive setup #2
A Low-Cost, Expandable, Open-Architecture Grinding Machine Control System
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
A Low-Cost, Expandable, Open-Architecture Grinding Machine Control System
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
A Low-Cost, Expandable, Open-Architecture Grinding Machine Control System
Signal Interface Unit
To convert one set of signal configurations to be compatible with the machine wiring
A Low-Cost, Expandable Open-Architecture Grinding Machine Control System
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
A Low-Cost, Expandable Open-Architecture Grinding Machine Control System
Rack assembly with connecting cables
Electrical cabinet :- I/O
A Low-Cost, Expandable Open-Architecture Grinding Machine Control System
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
A Low-Cost, Expandable Open-Architecture Grinding Machine Control System
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
A Low-Cost, Expandable Open-Architecture Grinding Machine Control System
Automatic Plunge Cycle
A Low-Cost, Expandable Open-Architecture Grinding Machine Control System
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
A Low-Cost, Expandable Open-Architecture Grinding Machine Control System
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
A Low-Cost, Expandable Open-Architecture Grinding Machine Control System
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.
A Low-Cost, Expandable Open-Architecture Grinding Machine Control System
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
A Low-Cost, Expandable Open-Architecture Grinding Machine Control System
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
….
A Low-Cost, Expandable Open-Architecture Grinding Machine Control System
Some System Parameters
A Low-Cost, Expandable Open-Architecture Grinding Machine Control System
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.
A Low-Cost, Expandable Open-Architecture Grinding Machine Control System
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
A Low-Cost, Expandable Open-Architecture Grinding Machine Control System
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 ???
A Low-Cost, Expandable Open-Architecture Grinding Machine Control System
Thank you for your attention.....