A framework for integrated process

ugliestmysticAI and Robotics

Nov 14, 2013 (3 years and 8 months ago)

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A framework for integrated process
monitoring in grinding machine control

John Moruzzi

GERI / AMTReL

A framework for integrated process monitoring in grinding machine control

M. N. Morgan, X. Chen
,

D.R. Allanson

Introduction

A framework for integrated process monitoring in grinding machine control

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 is often 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.





Objectives and Innovation

A framework for integrated process monitoring in grinding machine control

An innovative new software
-
based design strategy is therefore proposed 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
of the new system, using a standardized format that will allow similarities
and synergies to be recognised and optimised.


The main items for consideration are:




Cycles and Part programmes

(Grinding, Dressing, Balancing)



Hardware features


(Connectors,Interfaces)




Communication features


(Protocols, data structures)



Operational features


(Functions, signals, data)



Software features


(Configuration, displays)




Control of the grinding process

A framework for integrated process monitoring in grinding machine control

A BASIC GRINDING CYCLE:

The fundamental
process parameters
for
grinding cycles are wheel and workpiece
speed. Additionally there will be defined
various infeed rates, infeed setpoints
(Coarse, Medium, Fine, Final size), reversal
points (Left and Right) and time dwells.


The machine control will execute a sequence
of moves to the programmed axis positions
at the appropriate speeds, and the
expectation is that a satisfactory part will be
produced.





Automatic Plunge Cycle

A typical automated cycle path is shown :


Monitoring of the grinding process

A framework for integrated process monitoring in grinding machine control

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.


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.


The devices will generally operate in
Manual

mode (operator control) or
Automatic
mode (machine control).












Key target functions:




Wheel Balancing

(vibration sensing / correction)




Touch Detection (Acoustic Emission or Power sensing)



Gauging

(Size / Position measurement)

The enhanced system is designed to accommodate fuller integration of process
monitoring equipment with the machine control system.

Quality Issues

A framework for integrated process monitoring in grinding machine control









Quality

Issues

Causes


Monitoring

Solution

Size

tolerance

System

deflections

Wheel

wear

In
-
Process

Gauging

Power

/

AE

monitoring

Surface

roughness

Wheel

selection

/

condition

Grinding

parameters

Post
-
Process

Gauging

Roundness

Grinding

parameters

Wheel

unbalance

Post
-
Process

Gauging

Wheel

balancing

Burning

Wheel

wear

/

dulling

Excessive

infeed

Power

monitoring

Spindle

wear

Wheel

unbalance

Wheel

balancing

In practice the physical variability of the process, such as wheel wear, machine
deflections, and temperature variations mean that adjustments to the
grinding parameters need to be made in order to improve the quality of the
finished part . The refinements to the process variables are often made in
response to changes in the part dimensions, surface finish or roundness, and
are identified through post
-
process measurements and operator experience.

Efficiency Issues

A framework for integrated process monitoring in grinding machine control

Key process efficiency issues:


Optimisation of machining and dressing times


Reduction in scrap, reworking, replacement of wheels etc.





Efficiency

Aims

Issue

Monitoring

Solution

Reduction

in
:

Air

grinding

time

before

machining


Power

/

AE

monitoring

Dwell

time

after

machining

Power

/

AE

monitoring

Excessive

wheel

dressing

intervals

Insufficient

wheel

dressing

intervals

Power

/

AE

monitoring

Optimisation

of
:

Infeed

rates

Power

monitoring

Material

removal

during

dressing

AE

monitoring

Safety Issues

A framework for integrated process monitoring in grinding machine control

Safety

Issues

Condition

Monitoring

Solution

Detection

of
:

Wheel

collision


AE

/

Power

monitoring

Wheel

failure

Unbalance

monitoring

Wheel

overspeed

Speed

monitoring

Key process safety issues:


Protection of operator from crash or failure conditions


Reduction in machine, wheel and part damage





Example Arrangement of Integrated System

A framework for integrated process monitoring in grinding machine control




CNC MAIN CONTROL




Major equipment suppliers

A framework for integrated process monitoring in grinding machine control



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:

Machine Control and Balancer features

A framework for integrated process monitoring in grinding machine control

Machine Control

Cycles

Plunge

Traverse

Dress

Commands

Start / Reset cycle

Select cycle

Set parameter

Integration

Machine logic

Custom software

Interfaces

Digital I/O

Analog signals

Serial

Bus

Network

Wheel Balancer

Cycles

Automatic balance

Manual balance

Neutral Balance

Sensors

Vibration

Rotation

Signals

Start / Reset cycle

Limits

Faults / Alarms

Data

Unbalance

Speed

The fundamental features, functions, quantities
and interfaces in a typical grinding machine
control are shown below.






The wheel balancer can be seen as
a simplified version of a machine
control system.





Functional similarities between equipment types:

Gauge and Touch Detector features

A framework for integrated process monitoring in grinding machine control

Touch Detector

Cycles

Touch monitoring

Burn Monitoring

Crash monitoring

Sensors

Acoustic Emission

Power

Special

(Force, Strain, ...)

Signals

Start / Reset cycle

Limits

Faults / Alarms

Data

Acoustic levels

Power levels

In
-
Process Gauge

Cycles

Diameter gauging

Flag gauging

Sensors

Gauging head

Rotation

Signals

Start / Reset cycle

Limits

Faults / Alarms

Data

Size

Position

There are also similarities in the functionality of the Gauging and Touch Detector
features.

Both use various sensors and channels to monitor and control different phases of the
grinding cycle. They will use different cycle parameters for machining different parts.






CNC Equipment Interfacing

A framework for integrated process monitoring in grinding machine control

System devices are
interconnected to
transmit and exchange:




Control signals



Status signals



Process data



Configuration data







CNC IO modules

CNC main module

Monitoring unit

PC unit

RS232

Digital IO

Ethernet

Profibus

Digital IO

Bus

Bus

CNC axis

drives

Digital IO

Bus

Analog

Ethernet

Equipment interfacing schemes

A framework for integrated process monitoring in grinding machine control

Digital I/O Interface



(Conventional)

24V DC opto
-
isolated digital inputs and outputs.

Each line set to 0 or 24V level = Low / High, On / Off, True / False.


Serial communications interface


(RS232, USB)

Traditional method between computer hardware. Direct Port
-
Port connection.


Bus / Fieldbus communications


(Profibus, Modbus, Interbus,…)

RS 485
-
based. Devices daisy
-
chained together :



1 x Master, n x slaves (with ID)


Network communications


(Profinet, DeviceNet,…)

Ethernet / TCPIP based.







Main schemes for interaction between devices
:

Dittel M5000 TD unit
-

signals definition

A framework for integrated process monitoring in grinding machine control

IO Interface table


Describes the connector

hardware and pin / line

assignments.


Identifies input and output

lines and numbers.


Identifies power supply/

ground lines.


Describes logic levels

(sense of signal)


Describes signal wiring

(Source / Sink)






BS VM9 TD unit
-

signals definition

A framework for integrated process monitoring in grinding machine control

IO Interface table
-

2


Equivalent table for similar

Touch Detector unit from a

different supplier.


Small set of names and

descriptors helps to identify

common or similar features.


Formalised / standardised

structure aids device

analysis and documentation.






Key interactions with devices

A framework for integrated process monitoring in grinding machine control

Main actions :




Device configuration




Device operation




Device monitoring


Main data:




Control, status and
alarm signals




Process signal values




Device parameters





What we would like our system to do…

Objectives for Open Control Systems:


Commercial or Industry standard hardware

(increasingly moving in this direction)



Modular software structures


(now commonplace)



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

A framework for integrated process monitoring in grinding machine control

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

applications:

Open Control Systems : previous work

OSACA / OSACA II



(1992, 1997 ESPRITIII)


Open Systems Architecture for Controls in Automation Systems


Participants:

Num, Fagor, Bosch, Siemens, Comau, Uni.Stuttgart & Aachen

OCEAN





(2002 Framework 5)

Open Controller Enabled by an Advanced real
-
time Network


Participants:

Homag, Fagor, OSAI, Fidia, Uni.Stuttgart & Aachen

OROCOS



(2000 …)

Open RObot COntrol Software


Participants:


Uni. Leuven & Collaborators (Laas, KTH, LVD, Flanders Mechatronics)

OCI




(1997)

Open Control Interface


Statham (LJMU AMTReL)

Outcomes:

Basic outcomes published but no recognised standards adopted.

Further developments kept “in
-
house” or public domain / Open Software

A framework for integrated process monitoring in grinding machine control

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 Layer


Object Instances:

Actual data items e.g. actual devices (e.g.
MyGauge
)


Level 3 :

Data Presentation Layer


Derived 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 Layer


API 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
.

A framework for integrated process monitoring in grinding machine control

Example ODI device implementation

A framework for integrated process monitoring in grinding machine control

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

TVM
9
_TD_Device

TDevice

TouchDetectorUnit_
2

TVM
20
_TD_Device

GaugeUnit

TVM
9
_GA_Device

BalancerUnit

TVM
9
_BA_Device

TDIOInterface

TInterface

DigitalIO(
1
)

TDV
004
_DIO_Device

Deva
.
get_digital_inputw

DigitalIO(
2
)

TBB
48
D_DIO_Device

BB
.
write_output_port(B)

VM
9
Unit
.
Serial

TSerial_Interface

Win
.
Com
1
.
Output

=

..

VM
20
Unit
.
Profibus

TProfibus_Interface

DevInitBoard()

TouchCycle
1
.
Active

TSignalState

TProcessSignal

AE
.
Channel(
1
)
.
Value

TDataValue

TProcessData

AE
.
Channel(
1
)
.
Gain

TParameterValue

GapCycle
.
State

TGapElim_Cycle

TProcessCycle

GaugeCycle
2
.
State

TGauge_Cycle

AutoBalanceCycle
.
State

TAutoBalance_Cycle

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

Applications of the ODI Library

A framework for integrated process monitoring in grinding machine control

Overall software and hardware structure:

(& why it is useful beyond this application!)






OPI Device Library


TDeva_004

TVM9_TD

TVM9_BA

TVM20_TD

TDTLM5000_BA

…..

T1300X_Panel

THM_UH1Control


BS VM9BA

BS VM9TD

BS VM20SYS

BS VM20BA

BS VM20TD

Dittel

M5000 MA

J&S 1300X Panel

Dittel

AE4000

CNC Program

(Machine control)


e.g. J&S 1300X

Monitor Program

(Standalone)



HeatMiser

UH1

Deva

004

User Application






Virtual Device






Actual Device






A framework for integrated process monitoring in grinding machine control


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:

A framework for integrated process monitoring in grinding machine control


VM20 TD Device


Status data

Status Data read
Cyclically

from a data
BYTE

at a defined memory
ADDRESS


-


Call Method

VM20_TD.GetStatus

Individual data items decoded from
BIT

settings and written to a standard data structure


Valid Status data used directly by application program





Status Data : Device => Control


feedback & event signals

A framework for integrated process monitoring in grinding machine control


VM20 TD


Monitor & Control data

Monitor Data :


Device => Control

Process data values


Selectable content:



AE1 & AE2



AE1 & PWR1



…….

Control Data :


Control => Device

Activate features


Select program


Start / Reset Cycle

A framework for integrated process monitoring in grinding machine control


VM20 TD


Parameter & Config data

Parameter Data :


Device <=> Control



Config 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

HMI and other features

In addition, the facility to
Record

live process data and store in a common format


log file is provided.

A framework for integrated process monitoring in grinding machine control


Once we have established communications and control of a device, the operator


of the Application program should be presented with a standard HMI display for


interaction with the various devices.






Therefore a library of Display and
Editing Components is included:


Graph


Edit box

LED


Numeric Keypad

LEDBar


Data Name text

DRO


Data Units text

Buttons


……..

Summary of studied ODI devices

A framework for integrated process monitoring in grinding machine control

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 / planned:


Deva004



Motion Control


(Digital IO)

Fanuc CNC


CNC Interface


(Ethernet / FWLIB)


Heatmiser UH1


Building Heating Control

(RS485 / TCPIP)







Summary

A framework for integrated process monitoring in grinding machine control



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



A procedure for documenting and specifying the individual features of various equipment
examples into a common format has been developed.



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



A Common 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.

And finally...

Any Questions ???

A framework for integrated process monitoring in grinding machine control


Thank you for your attention.....