Universität PaderbornAG Softwaretechnik

Towards Modular Modeling and SimulationTowards Modular Modeling and Simulationof Production Control Systemsof Production Control Systems

Holger GieseHolger Giese und Ulrich A. Nickel und Ulrich A. NickelAG Softwaretechnik, Universität PaderbornAG Softwaretechnik, Universität Paderborn

Warburger Str. 100, 33098 PaderbornWarburger Str. 100, 33098 Paderborn{hg|duke}@upb.de{hg|duke}@upb.de

Universität PaderbornAG Softwaretechnik

Holger Giese und Ulrich A. Nickel: Towards Modular Modeling and Simulation of Production Control Systems 2/15

Production Control System Executable UML Class Model & Simulation Modularity & Separation for Executable Models Requirements & Simulation Conclusion & Future Work

Overview

Universität PaderbornAG Softwaretechnik

Holger Giese und Ulrich A. Nickel: Towards Modular Modeling and Simulation of Production Control Systems 3/15

Production Control System (PCS)

Flexible distributed control is „complex” to build

Frequent adaptation to new requirements or changes in the topology are required

Programming languages (Ada, C, …)

Test & code corrections in the production environment

Design and maintenanceMethodology & UML

Avoid long downtimes Verification is hard problem

Simulation

Universität PaderbornAG Softwaretechnik

Holger Giese und Ulrich A. Nickel: Towards Modular Modeling and Simulation of Production Control Systems 4/15

Application SoftwareGate

Bus Interface

Sensors/Actors

Processor Nodes ID Identification Unit

Data Links St Stopper

Travel Direction M Motor

Signal Direction S Sensor

ID St MS

S

PCS: Overview & Elements

Universität PaderbornAG Softwaretechnik

Holger Giese und Ulrich A. Nickel: Towards Modular Modeling and Simulation of Production Control Systems 5/15

Executable UML Class Model

UML Model describes: possible system

topology Reactive overall

class behavior (Statecharts, SDL,..)

Advantages: OO concepts: e.g.,

class encapsulation Visual modeling High level viewSignal

Gate

Track

Universität PaderbornAG Softwaretechnik

Holger Giese und Ulrich A. Nickel: Towards Modular Modeling and Simulation of Production Control Systems 6/15

Specification

Topology

Visuali-zation

Simulation

Control software

Simulation kernel

Java Virtual Machine

JavaReflect

Dobs

Production-order

Codesynthesis

Hardwareconfiguration

Executable UML Model Simulation

Universität PaderbornAG Softwaretechnik

Holger Giese und Ulrich A. Nickel: Towards Modular Modeling and Simulation of Production Control Systems 7/15

Classes & Simulation

Simulation result: Can detect coordination

problems: deadlock, … Provides insight into

system dynamics (tinkering style)

Limitations: System has to be

complete (closed) Observations do only hold

for very restricted form of subclass refinement

Universität PaderbornAG Softwaretechnik

Holger Giese und Ulrich A. Nickel: Towards Modular Modeling and Simulation of Production Control Systems 8/15

Modularity: Overall Synchronization

Component Spec.: overall behavior arbitrary structuresAbstraction: combine processes build abstract process behavior for layer C depends on (A || B) no abstraction barrier for used layersLimitations: State explosion problem (propability for error

detection) Component exchange preserve results only when

very restricted conformance realtion holds

A

B

C

Layer C

Universität PaderbornAG Softwaretechnik

Holger Giese und Ulrich A. Nickel: Towards Modular Modeling and Simulation of Production Control Systems 9/15

Modularity: Contract

Reduce class behavior to external visible/relevant contract behavior

Multiple contracts (UML-RT ports)

Universität PaderbornAG Softwaretechnik

Holger Giese und Ulrich A. Nickel: Towards Modular Modeling and Simulation of Production Control Systems 10/15

Modularity: Partial Contract Border

Component Spec.: set of contract behavior layered structures

Abstraction: specification for layer

C is C1 || ... || C4 partial model simulation & analysis

arbitrary usage of provided contracts C5 || C6 || C7 assumed for used contracts

Limitation: embedding restricted to layered structures

C1

C2

C3

C4

C7

C6

C5

Contracts are design elements, but the by abstraction steps derived abstract

processes are not!!

Layer C

Universität PaderbornAG Softwaretechnik

Holger Giese und Ulrich A. Nickel: Towards Modular Modeling and Simulation of Production Control Systems 11/15

Modularity: Open PCS

Factory as open system within and out contracts (ports): possible Environments? embedding?

Universität PaderbornAG Softwaretechnik

Holger Giese und Ulrich A. Nickel: Towards Modular Modeling and Simulation of Production Control Systems 12/15

Modularity: Implicit Component Behavior

support even for set of contract behavior

and implicit dependencies Embedding only restricted

by demand to ensure acyclic dependencies

Abstraction: specification for C1, …, C4

Advantage: More flexible embedding when independent

C1

C2

C3

C4

C7

C6

C5

Component C

Universität PaderbornAG Softwaretechnik

Holger Giese und Ulrich A. Nickel: Towards Modular Modeling and Simulation of Production Control Systems 13/15

Modularity: Implicit Component Behavior

Open factory with implicitcomponent behavior: implicit environment embedding rule:

“depend has to remain acyclic”

Universität PaderbornAG Softwaretechnik

Holger Giese und Ulrich A. Nickel: Towards Modular Modeling and Simulation of Production Control Systems 14/15

Requirements & Simulation

Requirements are describedScenario-oriented: external view system may realize

suitable interleaving for multiple parallel requested tasks

Factory Simulation: use for checking use for run-time

assertions

Universität PaderbornAG Softwaretechnik

Holger Giese und Ulrich A. Nickel: Towards Modular Modeling and Simulation of Production Control Systems 15/15

Conclusion & Future Work

Modeling PCS: strong requirements for control

software methodology & UML-RT code synthesis and simulation (partial)Validation via simulation: early failure detection interactive “testing”Modular simulation improved separation modularity & scalability

Future Work

• Realize extended concept

• Integrate time support