System Analysis Using Multiple Expert Tools

DOE Update April 18, 2011

Ram Vijayagopal Argonne National Laboratory

Sponsored by David Anderson & Lee Slezak

This presentation does not contain any proprietary, confidential, or otherwise restricted information

Overview

Need for detailed vehicle models Interconnection of expert tools - Challenges Interface process definition

– Interface architecture – Interface rules

• Examples : GT Power, AMESim, CarSim

Autonomie for system integration Appropriate use of detailed models Case study

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Need for Detailed Vehicle Models

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Quick evaluation of new technologies Shortens the design time Expert system tools exist

– Technology exists for linking them

Engine GT-Power

Transmission AMESim

Veh.DynamicsCarSim

DriverEnvironment

Vehicle Controller

Vehicle Propulsion Architecture

Interconnect expert system tools to build detailed vehicle models

Interconnection of Expert Tools

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Challenges – I/O formats – Unit conversion – Documentation – Path settings, Environment variables – Compiler, solver settings – Supporting files, APIs – Signal name translation, Sign conventions – Other tools specific & even version specific properties

Tools considered – GT-Power, AMESim, CarSim and many more

Technology exists

Solution: Define a common interface process & automate it.

*.dat *.par *.ame *.c

Overview - Interface Process Definition

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Interface architecture definition – Documentation, Re-usability

Interface rules definition – Tool specific checks – System specific ‘Information exchange’ needs – Simulation specific requirements

Experts can define the process. Entire organization can use it

Matlab scripts Expert tool APIs

A modeling environment to automate & implement the process

Autonomie Used for System Integration

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Model documentation

Expert 1 : Tool 1

Model documentation

Expert 2 : Tool 2

Model documentation

Expert 3 : Tool 3

System specific information exchange needs

Tool specific checks

Simulation specific requirements

Expert 4 : System integration Automated interface Detailed vehicle model

Common Interface Architecture Definition

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S-Function

Output signal

formatting

Input signal

formatting

Wrapper built around s-function – Automated for different tools – Supporting files provide information about I/O signals

• *.dat, *.ame, simfile etc.

– Documentation of the model generated automatically

XML

New format, better documentation. Critical for interface & sharing of the models

Interface Rules - 1 Tool Specific Checks

AMESim – Environment variables – Compiler selection

CarSim – Register automation server

GT Power – Version specific changes

Path setting – include all solvers in Matlab path

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Tool specific checks are done while starting the vehicle simulation tool

eval(['!ameload ',amesim_ame_file]) ……… ameputpaliases(….,…..,…..)

Interface Rules - 2 System Specific Information Exchange Needs CarSim interface model initialization

– Invoke CarSim, Launch CarSim if needed – Generate simfile automatically – Read parameters needed for vehicle control

• vehicle mass, wheel radius, etc.

GT Power

– Parameters can be read from the .dat file.

AMESim

– Use APIs to set gear ratios on the AMESim model

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h = actxserver('CarSim.Application'); h.Yellow('#ALTPATH',user_dir); ………. h.RunButtonClick(n);

Information exchange

between models

Solver settings Step time Supporting files Result analysis

set_param(veh_mdl, 'SolverType', 'Fixed-step'); set_param(veh_mdl, 'Solver', 'ode4'); set_param(veh_mdl, 'FixedStep', delta_t) copyfile(tmp.source_file,tmp.dest_file)

Interface Rules - 3 Simulation Specific Requirements

Engine GT-Power

Transmission AMESim

Veh.DynamicsCarSim

DriverEnvironment

Vehicle Controller

Vehicle Propulsion Architecture

Build Vehicle Using Systems Defined by Experts

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dat

init file

ame

init file

sim file

init file

Engine system

Transmission system

Vehicle dynamics system

Appropriate Use of Interface Simplify detailed models for faster simulations

Automated process to run a component on a virtual test bench Detailed model are used to generate steady state maps Maps used to run default Autonomie models

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Automated component characterization process

initialization data

Case Study: Overview Effect of Steering on Fuel Economy

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Vehicle dynamics : CarSim – Define the road – Takes in torque from transmission – Speed feedback for driver

Engine – Autonomie model – Fuel data generated from GT Power

Autonomie – GUI for model/system selection – Models rest of the vehicle – Automatic model building – Enforce interface rules – Result analysis capabilities

Case Study: Effect of Steering on Fuel Economy Appropriate Use of Multiple Tools

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CarSim

Engine initialization data automatically generated

from GT-Power

Autonomie

Build & Run Models Automatically Automatic building saves time and avoid errors Automatic enforcement of interface rules & checks Post processing capabilities

model building

Running external tools

resu

lts

Simulation Results Overview Different steady speeds on straight

& circular roads – Effect of turning – More torque from engine, more fuel

Use expert tools to analyze results – Saves results for all tools involved

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Autonomie Result analysis

CarSim Result analysis

Conclusion

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A common interface architecture is developed. This is adaptable to any tool that supports a Simulink interface.

Automated the interface process to ensure that all tool specific requirements are satisfied

Interface automation demonstrated for GT-Power, AMESim, CarSim

Autonomie provided user interface for model/system/process selection and enabled model sharing, and knowledge sharing

Demonstrates a methodology for detailed simulation studies