MODELING & SIMULATIONT H R O U G H O U T Y O U R S Y S T E M L I F E C Y C L E

CSD&M PARIS – DEC. 2020

A contribution to the reconciliation of MBSE methods

Philippe Fiani - R&D Manager at Sherpa Engineeringp.fiani@sherpa-eng.com

www.sherpa-eng.com

Introduction▪ MBSE is increasingly being adopted in

industries

▪ The challenge is more in the appropriate

choice of method and tools and their

instantiation to specific issues and needs

▪ The choice is constrained by corporate

considerations and by the maturity of the

existing toolsEngineering a System

Tools Methods

Process

The challenge▪ Two engineering methods coexist

▪ CESAM / ARCADIA

▪ Similarities in their purpose / differences in their

implementation

▪ How these two methods can be aligned?

▪ Industrial use-case

▪ Ensuring a link with simulation models

++ Simulation

CESAM

Systems architecture pyramid Systems architecture matrix (9 views)

4

CESAMES Systems Architecting Method

ARCADIA

5

Architecture analysis & design integrated approach

Operational Architecture

System Architecture

Logical Architecture

Physical Architecture

Model l ing & Simulat ion of CPS*

▪ Objectif: ensure simulation capabilities

▪ Precise pre-definition of flows

▪ Homogeneous nature of the components: equations can be specified at a selected abstraction level

▪ Functional energetic modeling

▪ High level abstraction used for functional design

▪ Flows: Energy, Matter, Information

▪ Components: generic transformation

▪ Multi-physical and control modeling

▪ Classical system representation used in Model-Based Design approach

▪ Flows: physical and control

▪ Physical components and Control algorithms

6

Consumption2

Production Distribution

Transformation

Consumption1request

supply

Inverter

Local ControlStorage

Electric Motor

ElectricStorage

Body

Local ControlMotor

Global Control

physical flows

control flows

Functional energetic modeling

Multi-physical and control modeling

* CPS: Cyber-Physical Systems

Funct ional Energet ic Model l ing

▪ Bidirectional EMI flows

▪ Each component provides basic feature with a set of consistent methods

▪ The use of components ensure modularity and flexibility

▪ Each component only reacts to its inputs

▪ Components can be connected without knowing how the other one works

▪ The resulting architecture is intelligible and allows tackling complex controlled system

7

Funct ional Energet ic Model l ing & Simulat ion

8

▪ The flow types are: energy, matter and information

▪ Each function can be decomposed in a triadic basis

T TimeStorageAccumulation

S SpaceTransport, TransmissionDistributionInjection, extraction

F Form

TransformationConversionProductionDestruction, consumption

Same concepts“Energy-Mater-Information based”

Definition model Simulation model

Mult i -Physical Model l ing & Simulat ion

9

Same concepts“Bond-Graph based”

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EOF Mechanical Power GeneratorReduction Gear

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measure

setpoint

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100

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time [s]

pow

er

[W]

0 1 2 3 4 5 6 7 8 9359

360

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volt

ag

e [

V]

EOF Mechanical Power GeneratorDC Voltage Source

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ent

[A]

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time [s]

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RES_t

ResistTorqueFcn

T0

ResistTorque

GraphsInitialization

RES_CTRL

RES_PowGen

SET o o o

HMI_EOF_MechPowGen[RES_EOF_MechPowGen]

[RES_Control]

[RES_Control]

[RES_EOF_MechPowGen]

CT

RL

RE

S

EOF_MechPowGen

SET

MEAS

RES

CTRL

EOF Mechanical Power Generator

Angular Speed Controller

Control_EOF_MechPowGen_AngSpeed

<Angular_Speed>

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RES

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portB

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RE

S

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[SET_CtrlElecMach]

[RES_SynchElecMach][RES_GearRed]

[RES_CtrlDCAC_Conv]

[RES_Control]

[RES_SynchElecMach]

[RES_CtrlDCAC_Conv]

[RES_GearRed]

[SET_CtrlElecMach]

[RES_Control]

0.5 , Left

ElementPort

CT

RL

RE

S

SET

MEAS

RES

CTRL

Synchronous Electric Machine

DQ Current Controller

Control_CtrlSynchElecMach

1

CTRL

RES_CtrlElecMach

RES_Sy nchElecMach

RES_CtrlDCAC_Conv

RES_Control

RES_GearRed

Definition model Simulation model

Reconcil iation

▪ Modeling an aircraft electric green taxiing

system

▪ Following the precepts of CESAM framework

▪ Using the Eclipse Capella which is based on

Arcadia system engineering method

▪ Using the Papyrus-PhiSystem profile to ensure

the link with the simulation models

EGTS

System model l ing with s imulat ion perspect ivesN

eed

Solu

tio

n

Customer Operational Need Analysis

SystemNeed Analysis

Logical ArchitectureDesign

Physical ArchitectureDesign

Functional Vision{functions}

Constructional Vision{technical components}

Operational Vision{missions}

Cyber-Physical Systems

Representation

Multi-physicalmodeling

(bond graph based)

Functional modeling

(EMI based)

❑ Actors and entities❑ Operational capabilities❑ Scenarios, activities and

interactions

❑ Missions❑ External Functions❑ Scenarios and interactions

❑ Logical components (internal functions) and connections

❑ System states❑ Scenarios

❑ Technical components and connections

❑ System states❑ Scenarios

System def init ion and evaluat ion

12

Evaluation (simulation)

Scenarios Verdicts

Scenario Generation

Architecture Optimization

Result AnalysisTransformation

properties →models

Scenarios Requirements

properties

Simulation resultsSimulation inputs

Simulation models

Physical /Constructional

Operational (customer)

Logical /Functional

System /Operational

Operat ional (customer) model l ing

13

▪ Objectives▪ Identification of all the use cases, scenarios

and requirements including the System of Interest (SoI) over the life cycle

▪ Agreement on the customer needs

▪ Simulation▪ Explicit definition of the needs

▪ Model verification

▪ Detection of inconsistencies in the specification (e.g. incompatible performance between several scenarios)

▪ Method▪ Use of a black box representation

Operat ional (customer) model l ing

▪ State diagram used to represent the life cycle of the SoI▪ Take off, Flight, Landing, Taxiing to gate, Night stop …

▪ Operational scenario represented by a sequence diagram▪ Pilot / cockpit

▪ Aircraft Auxiliary

▪ Wheel

14

Aircraft electric green taxiing system

System /Operat ional model l ing

▪ Objectives▪ Identification of a functional architecture

allowing to realize all the use-cases (or capabilities)

▪ Agreement on the expected results of the SoI

▪ Simulation▪ Explicit definition of the expected results

▪ Functional (external) architecture verification

▪ Method▪ EMI representation can be used

▪ Functional chains are useful to help and verify transition between the different views

15

A functional chain is a sequence of linked functions allowing to define a use case scenario

System /Operat ional model l ing

▪ High level function (external) architecture▪ Internal functions

▪ Electrical conditioning

▪ Torque generation

▪ Wheel coupling

▪ Aircraft motion control

▪ Thermal conditioning

▪ External entities

▪ Wheel, Cockpit, Aircraft auxiliaries …

▪ Use of a System Architecture diagram (system analysis stage)

16

Aircraft electric green taxiing system

Use of a functional chain to represent/verify a use case scenario

Logical /Funct ional model l ing

▪ Objectives▪ Specification of the operation functions and

the control functions

▪ Some safety functions can be introduced (monitoring, diagnostic …)

▪ Simulation▪ Support to the system analysis (quality,

performance and safety)

▪ Control system analysis

▪ Method▪ Separation of control systems and operating

systems

▪ Multi-physical representation is generally used

▪ Physical and control flows must be defined

17

Logical /Funct ional model l ing

▪ Functional architecture▪ Separation of control systems (green blocks) and operating

systems (orange blocks)

▪ Scenarios to support each of the logical architecture capabilities

▪ Use of a Logical Architecture diagram

18

Aircraft electric green taxiing system

Physical /Construct ional model l ing

▪ Objectives▪ Definition of the Breakdown Structure (SW,

ECUs & HW)

▪ Introduction of solutions for structural requirements (redundancy, segregation …)

▪ Taking into account the human organization

▪ Simulation▪ Support to the system analysis

▪ Quality, performance, safety + cybersecurity

▪ Specific requirements of the electronic architecture (real-time specification, CPU performance and faults)

▪ Method▪ Clustering must be compliant to the

human/entities organization

19

Physical /Construct ional model l ing

▪ Breakdown structure, areorganization is necessary

▪ To take into account the entity organization

▪ To separate SW/HW parts

▪ Functional chains can also be used to support capabilities (in association with scenarios)

▪ Use of a Physical Architecture diagram

20

Aircraft electric green taxiing system

An interesting view for simulation issues and safety analysis

Modell ing an electric vehicle ▪ Design the EMS of a PHEV

▪ EMS: Energy Management System

▪ PHEV: Plug-in Hybrid Electric Vehicle

▪ This example presents a high-level

functional model (external/internal view)

▪ Description model using CAPELLA

▪ Simulation model using PhiSim

Appl icat ion to HEV energy management

Thermal Comfort

Electrical Aux.

Vehicle Motion

Gaz Station

Elec. Source

TransformationStorage

Storage TransformationDistribution

Transformation

Distribution

Distribution

22

System /Operat ional model l ing

23

▪ Use of a System Architecture diagram to describe the interaction with the structured environment

▪ This view can be considered as a link between the operational and the functional visions (CESAM framework)

Analogy between system & simulat ion models

System architecture Simulation model

24

External Resources Energy Management

System

Energy Consumers

Energy Management System

Vehicle Energy Management System (external view)

Analogy between system & simulat ion models

System architecture Simulation model

25

Vehicle Energy Management System (internal view)

HEV energy management

Vehicle Analysis Energy Management Vehicle Performances

Electric SOC

Fuel SOC

Electric, Fuel, Braking

26

Simulation of the global vehicle (energy viewpoint) → energy management strategy evaluation

Conclusion▪ This work shows that 2 methods known to

be incompatible can be used jointly in an

industrial application

▪ This is an important point for the

deployment of MBSE

▪ Since industrials need to choose a method and a

mature and comprehensive tool

▪ Since tool makers need to rely on a method

chosen by industrials

Value Chain

Tool providersMethods

Developers

IndustrialEnd users

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