A LOW-COST, EXPANDABLE, OPENARCHITECTURE GRINDING
MACHINE CONTROL SYSTEM
John Moruzzi
AMTReL
Director of Studies: Dr Michael Morgan
A Low-Cost, Expandable, Open-Architecture Grinding Machine Control System
AMTReL Jones & Shipman 1300X
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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
Open CNC Interface
(Y Chen)
(C Statham)
High speed Internal grinding
Industry co-operations (Timken, Lucas, …)
Fluid delivery methods, nozzle design
AE monitoring
Dressing tool control (fluid coupling)
A Low-Cost, Expandable, Open-Architecture Grinding Machine Control System
Aims of the project
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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
Machine
Control system
Familiarity with machine & electrics
Initial “desktop” PC control :
ISA bus motion control card
No Digital I/O card
Standard mouse / keyboard / monitor
Re-commission hardware
Move axes
Replace workhead drive
Modifications to wiring
Initial Software
Disable hardware limits
Remove original control panel
A Low-Cost, Expandable, Open-Architecture Grinding Machine Control System
Windows 2000 (XP), Visual Basic
Programming familiarity
Axis configuration (Utility S/W)
Axis movements (Utility S/W, libraries)
Simple grinding cycles
Simple cycle parameters
No I/O features
Phase 2 Objectives
Machine
Modifications to hardware
Optimise axes (drives)
Replace original digital I/O wiring
Activation of
workhead
external wheel
coolant pump
Control system
New “industrial” PC control :
Rack mount case with Mini-ITX PC board
PCI bus motion control card
Digital I/O from motion card
Standard mouse / keyboard / monitor
LCD / Touchscreen monitor
Developed software
Modifications to wiring
Enable hardware limits
Interface to original control panel
Interface external control devices (Power, AE)
Implement new control panel
A Low-Cost, Expandable, Open-Architecture Grinding Machine Control System
Windows XP, Visual Basic / .NET
Program design & implementation
Parameter definition & management
Enhanced axis moves (MPG)
Standard grinding cycles
Enhanced cycle programming
Initial IO features
RS232 connectivity
Architecture of a CNC system
Main Control
Executor
IO routines
Scheduling, program execution, monitoring
Safety
Cycle management
Motion Control
Machine logic
HMI, programming, Digital, Bus
Sequencing, monitoring
Axis movements, motors
Process optimisation
Adaptive / Intelligent Control
In-process Gauging
Touch Detection
Wheel balancing
Probing
Adaptive strategy
Parameter modification
Selection strategy
Rule / Case based
Process models & rules Kinematic, Compliance
Database
Learning strategy, data
Diameter, Shoulder
AE, Power
Auto / Manual
A Low-Cost, Expandable Open-Architecture Grinding Machine Control System
New Components
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A Low-Cost, Expandable, Open-Architecture Grinding Machine Control System
Workhead servo drive
Industrial PC
Motion control card
Touchscreen monitor
Console switches / lamps
Cabling / connectors
Grinding Wheel speed and Control
Wheelspeed
Rotational speed
ns (RPM)
Surface speed
Fixed on 1300X machine , can be changed with gearing / pulleys
Control buttons:
SB4
SB3
Start Wheel
Stop Wheel
Control relays:
KA5
KA12
KA13
Wheelhead Stop Override
Enable Internal Wheelhead
Enable External Wheelhead
A Low-Cost, Expandable, Open-Architecture Grinding Machine Control System
Green
Red
vs (m/sec)
(3 ratios)
Workhead speed and control
Workspeed
Rotational speed
nw (RPM)
Surface speed
Variable on most grinding machines
Open-loop motor drive control
Calibration
Control buttons:
Control relays:
W+ WSB8
SB7
KA4
KA6
KA7
Controlled by operator / program
3rd axis on motion card
Reference Voltage => speed
Speed Down / Up
Start Workhead
Green
Stop Workhead
Red
Workhead Stop Override
Workhead Start Override
Workhead Stop Relay
A Low-Cost, Expandable, Open-Architecture Grinding Machine Control System
vw (m/sec)
Deva 004 : Axis servo setup
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
Z axis parameters
PITCH = -10.0000
COUNT = 10000.0000
MAXVOLT = 3000 (2150)
MAXSPEED = 60
MAXACCEL = 60
GAIN KV = 15
SPEED = 25
Also :
Adjust servo drive amplifier settings, to give
satisfactory response characteristics.
Tuning of amplifier trim-pots
Optimization / minimization of drift and overshoot
A Low-Cost, Expandable Open-Architecture Grinding Machine Control System
Axor MTS 400
VEL
Offset
kV
Der
Fine speed adjustment
Zero volt drift compensation
Dynamic response (gain)
Derivative gain
Workhead drive setup #1
Original drive unit
(with choke)
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Original transformer
(single phase)
Non-standard drive and transformer (undocumented, unsupported)
Non-functioning
A Low-Cost, Expandable, Open-Architecture Grinding Machine Control System
Workhead drive setup #2
New servo drive unit
wheel power monitor
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New transformer
(3 phase 2kW)
A
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 Low-Cost, Expandable, Open-Architecture Grinding Machine Control System
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
Conn 2
Conn 3
Conn 4
Conn 5
Conn 6
15W D
15W D
9W D
15W D
15W D
9W D
Axis 0 encoder inputs
Axis 1 encoder inputs
Axis 0 , 1 servo outputs
Axis 3 encoder inputs
Axis 4 encoder inputs
Axis 2 , 3 servo outputs
New PCI bus Motion card – 4 axes on 1 board + flyer cables:
Conn 1
Conn 2
Conn 3
Conn 4
IO2
15W D
15W D
15W D
15W D
25W D
Axis 0 encoder inputs / limit signals
Axis 1 encoder inputs / limit signals
Axis 2 encoder inputs / limit signals
Axis 3 encoder inputs / limit signals
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 cabinet
To 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
Control PC
Interface
Machine
Encoder 0
Encoder 0
Encoder 1
Encoder 1
Encoder 2
Encoder 2
Encoder 3
Encoder 3
Servo 0, 1, 2, 3
Servo 0 , 1
Servo 2 , 3
IO1 Inputs, Outputs
Inputs 0..15
IO2 Inputs, Outputs
Outputs 0..11
Additional
Additional
A Low-Cost, Expandable Open-Architecture Grinding Machine Control System
Signal Interface Unit cont...
Implemented as 2U high 19” rack enclosure
Rack assembly with
connecting cables
A Low-Cost, Expandable Open-Architecture Grinding Machine Control System
Electrical cabinet :- I/O
I/O terminals
Relay board
Fuses
A Low-Cost, Expandable Open-Architecture Grinding Machine Control System
Control PC hardware
IEI Kino 945 GSE
Further equipment
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2U 19” rack PC case with PSU
Operating system Windows XP
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8.4” LCD Touchscreen (VGA, RS232)
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Deva 004 Motion card (4 axis + I/O)
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2U 19” rack for signal interfacing
Blank 19” rack panels
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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
Low-Cost, Expandable Open-Architecture Grinding Machine Control System
Control PC hardware cont...
Front of 19” control console:
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VM20 unit 3U (balance / touch)
Blank panel 1U
PC rack unit 2U
Signal Interface unit 2U
An Introduction to Grinding Machine Control Systems
Inside of control console:
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Axis cabling
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I/O cabling
Cross connections
Software panel – main screen
Main user interface
Grinding mode
and program
control
Z axis status
and Jog
Cycle start / stop
and status
Machine
functions
control
X axis status
and Jog
Manual axis
control
Low-Cost, Expandable Open-Architecture Grinding Machine Control System
Software panel – program screen
Cycle programming - Traverse
A Low-Cost, Expandable Open-Architecture Grinding Machine Control System
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 wheel
Wheel 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 wheel
Wheel 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
Cycle State Machine
Cycle parameters
PlungeCoarseInfeed As Double
PlungeFineInfeed As Double
PlungeFineDia As Double
PlungeStartDia As Double
PlungeSizeDia As Double
PlungeDwell As Double
Auxiliary variables
WheelSpeed As Double
WorkSpeed As Double
WheelheadOn As Boolean
WorkheadOn As Boolean
CoolantOn As Boolean
Motion parameters
dblXMovespeed As Double
dblXRapid As Double
dblXCoarseFeed As Double
dblXFineFeed As Double
dblXInfeed As Double
dblXInfeedRate As Double
intXDwell as Integer
dblXStartPosition As Double
dblXFinePosition As Double
dblXSizePosition As Double
dblZReversePositionL As Double
dblZReversePositionR As Double
dblZStartPosition As Double
intFROSetting As Integer
blnFeedHold As Boolean
A Low-Cost, Expandable Open-Architecture Grinding Machine Control System
Interfacing of Peripherals 1
Connect to 1300X Operator Panel
via RS232:
Read Data String:
FRO value, button values, checksum
Write Data String:
Axis position displays, Workspeed
display, LED values, checksum
A Low-Cost, Expandable Open-Architecture Grinding Machine Control System
RS232:
Com 1,
9600 Baud,
No Parity
Interfacing of Peripherals 2
Connect to Balance Systems VM9 TD
via RS232:
Read Data String:
Signal values, Parameter values, checksum
Write Data String:
Operating commands, Parameter settings, checksum
A Low-Cost, Expandable Open-Architecture Grinding Machine Control System
RS232:
Com 2,
38400
Baud,
No Parity
• 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
• 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
A fundamental object could be of type Parameter,
with various Attributes and Operations
(i.e. Properties and Methods)
Class:
Parameter
Derived classes:
CycleParameter
AxisParameter
VM9 Parameter
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Properties:
Data Type
Decimal places
Group
Level
Value
Min Value
Max Value
Methods:
….
A Low-Cost, Expandable Open-Architecture Grinding Machine Control System
ReadValue
WriteValue
FormatValue
ResetValue
GetAddress
….
Some System Parameters
Axis Configuration
RS232 Configuration
XAxisChannel
XAxisPitch
XAxisCount
XAxisKV
XAxisMaxSpeed
XAxisMaxVolt
Port
Baudrate
ParityChecking
Handshaking
InBufferSize
OutBufferSize
As AxisParameter
As AxisParameter
As AxisParameter
As AxisParameter
As AxisParameter
As AxisParameter
Traverse Cycle
XCoarseInc
XFineInc
TraverseZFeed
TraverseStartDia
TraverseFineDia
TraverseSizeDia
Z0Dwell
ZRevDwell
TraversePasses
As CycleParameter
As CycleParameter
As CycleParameter
As CycleParameter
As CycleParameter
As CycleParameter
As CycleParameter
As CycleParameter
As CycleParameter
A Low-Cost, Expandable Open-Architecture Grinding Machine Control System
As RS232Parameter
As RS232Parameter
As RS232Parameter
As RS232Parameter
As RS232Parameter
As RS232Parameter
VM20 Balancer Function
MinimumTolerance
As BalanceParameter
MaximumTolerance
As BalanceParameter
MaximumUnbalance
As BalanceParameter
NominalSpeed
As BalanceParameter
UnbalanceMeasuringUnit As BalanceParameter
BalancingCycleTimeout As BalanceParameter
CollectorType
As BalanceParameter
BalancingHeadType
As BalanceParameter
OptionRPMOutput
As BalanceParameter
Universal Modelling Language
...?
The UML Class diagram allows us to
model the classes in the system
and their relationships.
Class diagrams :
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model a class as a rectangle.
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The top zone displays the class name.
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The middle zone contains the
class attributes.
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The bottom zone contains the
class operations.
A Low-Cost, Expandable Open-Architecture Grinding Machine Control System
Progress
So far.....
Reactivation of machine tool
Electrical modifications, new workhead drive
Initial software with old hardware
Development software with new hardware
Next steps....
Formal definition of software structure
Integration of Touchscreen
Connection with VM20 unit (RS232/Profibus)
Axis movement via MPGs: Improved driver
Axis configuration and movement
Familiarity with motion control package
Issues....
Implementation of simple cycles
Machine removed for workshop rebuild since
August 2011
Design and build of control unit, IO conversion
Developed basic interface design
New workshop with machines available
during April 2012 ?????
Communication with external equipment
VM9 Touch Detector unit with Hydrophone ?
A Low-Cost, Expandable Open-Architecture Grinding Machine Control System
And finally...
Thank you for your attention.....
Any Questions ???
A Low-Cost, Expandable Open-Architecture Grinding Machine Control System