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CIRP DESIGN SEMINAR 2003 12-14 may, 2003, GRENOBLECIRP DESIGN SEMINAR 2003 12-14 may, 2003, GRENOBLE

COOPERATIVE TOOLS FOR SPECIFICATION AND MODELLING OF COMPLEX SYSTEMS

Faiçal Miled, Denis Choulier, and Michel Ferney

Laboratoire M3M

Université de Technologie de Belfort-Montbéliard - 90010 Belfort Cedex (France)

Phone: 03 84 58 33 40 – Fax: 03 84 58 31 46

{faical.miled, denis.choulier, michel.ferney}@utbm.fr

University of technology of Belfort Montbéliard - http://www.utbm.frM3M LABORATORY

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Problem

Functional specification

Structural modelof the passive part

Validation of the structural model of the passive part

Control and simulations

Functional validation of the active part

Cla

rifi

cati

onC

once

ptu

alTools

Matrixial table

Petri nets

Bond graphs

Bond graph

simulation tools

….

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INDEX OF THE PRESENTATION

University of technology of Belfort Montbéliard - http://www.utbm.frM3M LABORATORY

II. SPECIFICATION APPROACH

QUANTITATIVE SPECIFICATION:

QUALITATIVE SPECIFICATION:

ACTIVE PART VALIDATION:

METHOD:

VI. CONCLUSIONS AND PROSPECTS

I. CLASS OF THE STUDIED SYSTEMS

III. APPLICATION: Automatic transmission of a scooter

IV. FUNCTIONAL MODELLING BY PETRI NETS

V. NEXT STAGE OF DESIGN PROCESS: Conceptual design

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Technical_System j

SUj SUj TRj

TRj WU

CUjCUj

Need Functions

Energy

HYBRID SYSTEM

I. CLASSE OF THE STUDIED SYSTEMS

ARCHITECTURAL DESCRIPTION:

Technical_System i

SUi SUi TRi

TRi WU

Need Functions Energy

* Power link

SU: Source Unit

TR: TRansmission

WU: Work Unit

CUiCUi

* Informations flow

CU: Control UnitTU

TU: Transitions Unit

LEGENDE

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Active partActive part WU Passive part Passive part

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Technical_System j

SUj SUj TRj

TRj WU

CUjCUj

Need Functions

Energy

HYBRID SYSTEM

I. CLASSE OF THE STUDIED SYSTEMS

ARCHITECTURAL DESCRIPTION:

Technical_System i

SUi SUi TRi

TRi WU

Need Functions

Energy

CUiCUi

TU

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Active partActive part WU Passive part Passive part

SD: Set to be Designed

SDi

SDj

TU manage discrete behaviour, its design depends on technological criteria

CUs manage continuous behaviour, their design depends on control criteria

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DIRECTIVES:

For hybrid system:

TRs are to be specified: They complete passive part (SUs and WU are preset )

CUs and TU are to be specified: They form the active part

Designers must establish strong interaction between passive and active parts: Passive part must verify control criteria

Our paper presents a methodology to establish coherent specifications of the SDs and TU

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SPECIFICATION

SDs , TU

The analyse of:

• SUs: Depends principally on its power characteristics;

• WU: Represents a translation of need functions;

II. SPECIFICATION APPROACH

An approach based on the states and transitions: Behavioural functions

The system to be conceived must reach operating states and ensure transitions.

SUs WU

ANALYSE

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The specification of:

• SDs and TU: Deduced from the analyse of SUs and WU.

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Objective: Identification of discrete behaviour

Means: Study transitions between states

- Supported by the use of a symbolic vocabulary to predict the system behaviour

- It represents the first level of abstraction for specifying system

QUALITATIVE SPECIFICATION:

QUANTITATIVE SPECIFICATION:

Objective: Study the continuous behaviour of each technical system

Means: Quantify states and transitions

- Supported by a quantification of states with specific parameters in relation with

power components

- It represents a second level of abstraction for specifying system

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In order to realize design, the transition is:

The pre-existent elements acts such that the transition:

 

AND Exist Possible Impossible 

 

Desired Ø

 

Not desired

SU

CONFLICT

CONFLICT

WU

TABLE OF CONSISTENCES:

NATURE OF TRANSITIONS:

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SU WU

nature of transitions between states of SU

States of WU

States of SU

nature of transitions between states of WU

States and nature of transitions

between states of TR

MATRIXIAL TABLE: A COOPERATIF TOOL

Ew1

Ewm

Ee1 Een

0

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X

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III. APPLICATION: Automatic transmission of a scooter

TR

SU

Existent elements:

* SU: Thermal engine

* WU: Back wheel

WU

The user instructions:

* Desired speed with maximum efficiency;

* Maximum speed;

* Disconnect engine.

Engine will be considerate as a modulated source: Modulation will be managed by CU(s)

We must control engine speed and Back Wheel Speed

TRANSMISSION ENVIRONMENT AND EXPRESSION OF THE NEED:

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0

SU

WUIdling engine

Ee2

Generator engine Ee3

Free wheel Ew1

Driving wheelEw3

Receiving wheel Ew2

Stand by engine Ee1

X X

0

0 0

0

0 X

X

0

0

0 1 1

0

1

1

0

Qualitatif states Matrixial Table

QUALITATIVE SPECIFICATION:

Receiver engine Ee4

Qualitative specification needs basic knowledge's of the system

The analyse of SU and WU implies SD and TU qualitative specification

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QUANTITATIVE SPECIFICATION:* The quantitative states related to Ee3 are:

–  Ee3,1: Maximum power;

–  Ee3,2: Maximum power engine efficiency.

e

Pe

0

Maximum-Power

X

0

0

0

Ee31

Ee32

Ew21

Ew22

Ew23

SU WU

X

X

p_max

1

m

Te

e0

Maximum-Power efficiency

r_max

1

m i: engine load

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* The quantitative states related to Ew2 are:

–  Ew21: Maximum torque applied to the wheel;

–   Ew22: Follow a speed instruction;

–  Ew23: Reach maximum speed.

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IV. FUNCTIONAL MODELLING BY PETRI NETS:

Petri Net is a hierarchical modelling tool:

We affect each qualitative state to Petri Net model place

We affect each quantitative state to a substitution place

METHOD:

P2 P3

T1

T2

T3T4

T5

P1

P21

P22

P23

T22

T21

T23

T24

T25

P23

P2

Hier-level Petri Net: Qualitative modelling Low level Petri Net: Quantitative modelling

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P1

P21

P22

P23

T22

T21

T23

T24

T25

P3

T1

T4

T3T5

P23

T2

P2

Validation is made by:

• Study of structural properties of Petri Net: Liveliness and accessibility;

• Simulation of different use cases.

ACTIVE PART VALIDATION:

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V. NEXT STAGE OF DESIGN PROCESS: Conceptual design

Se : Cm

m

I:Jm

1

: SeCpr

r 1

R(r)

Cm

m

I:Jm

1

I:Jeq

M.T.F .. m

0

MSe :u2

y1

y2

SU TR WU

MSe :u1

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P3

T5

P1

P21

P22

P23

T22

T21

T23

T24

T25

T1

T4

T3

P23

P2

T2

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VI. CONCLUSIONS

A cooperative tools for the synthesis of a valid technical specifications is proposed;

The multidisciplinary specification approach is based on a "state-transitions" language;

Matrixial tables allow for the visualisation and the application of consistence's rules which guarantee the coherence with the existing parts;

The passage to Petri Net models permits the validation of the active part;

The generation of TRs alternatives design should take into account control criteria, which are verified directly on bond-graph model;

Petri Net and bond-graph models form a complete virtual prototype of the application;

This prototype also makes possible to carry out qualitative, then quantitative simulations.

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AND PROSPECTS