Model-Driven Evolution of Software Architectures - Software and ...
Model-Driven Evolution of Software Architectures - Software and ...
Model-Driven Evolution of Software Architectures - Software and ...
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7.3. MigrationContext 133<br />
requests<br />
7.3 MigrationContext<br />
user<br />
supervisory controllers<br />
results<br />
activities triggers<br />
mechatronic subsystems<br />
regulative controllers<br />
transducers<br />
Figure 7.1:Machinecontrolcontext<br />
InthissectionwefirstdefinetheSMCcontext.Next,weintroducethemotivatingcase<strong>and</strong>runningexampleforthischapter:atypicalwaferscanner<br />
asproduced,forinstance,byASML.Inthissettingwebrieflydiscussthe<br />
keyconcernsforSMCsystemsingeneral. Theseconcernsneedtobeaddressedduringarchitecturemigration.Assuch,theyformthebasisforthe<br />
design<strong>of</strong>ournormalisation<strong>and</strong>transformationrules.<br />
7.3.1 SupervisoryMachineControl<br />
ThemachinecontrolcontextisclarifiedinFigure7.1.Fromasupervisory<br />
perspective,(sub)frames,transducers<strong>and</strong>associatedregulativecontrollers<br />
form mechatronic subsystemsthatexecute manufacturing activitiestoaddvalue<br />
toproducts.Therecipe-<strong>and</strong>customer-dependentrouting<strong>of</strong>multi-product<br />
flows,withvaryingoptimisationcriteria,constitutesone<strong>of</strong>thekey(supervisory)controlissues.Moreover,advancedmanufacturingmachinesmust<br />
respondcorrectly<strong>and</strong>reproduciblyto manufacturing requests,run-time events<br />
<strong>and</strong> results. Consequently,tointerpretmanufacturingrequests<strong>and</strong>toensurefeasiblemachinebehaviour,asupervisory<br />
machine controlcomponentis<br />
requiredtocoordinatetheexecution<strong>of</strong>manufacturingactivities[Ramadge<br />
<strong>and</strong>Wonham,1987;Sabuncuoglu<strong>and</strong>Bayiz,2000;V<strong>and</strong>enNieuwelaar,<br />
2004].<br />
Inpractice,ahigh-levelmanufacturingrequestistranslatedintovalid<br />
low-level machine behaviour using multiple, consecutive control-layers.<br />
This is supported by recursive application <strong>of</strong> the control context from<br />
Figure7.1: manufacturingactivities<strong>of</strong>onelevelbecomemanufacturing<br />
requestsforthenextleveluntilthelevel<strong>of</strong>themechatronicsubsystems.
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