Transcript Using Modelica models for Driver-in-the

Systems Engineering Specialists
Racing in Real-time:
Multi-domain modelling for Driver-In-the-Loop simulators
Copyright © Claytex Services Limited 2015
Claytex Services Limited
• Based in Leamington Spa, UK
– Office in Cape Town, South Africa
• Established in 1998
• Experts in Systems Engineering, Modelling
and Simulation
– Focused on physical modelling and
simulation using the open standards:
Modelica and FMI
• Business Activities
– Engineering consultancy
– Software sales and support
• Dassault Systemes
• rFpro
– Modelica library developers
– Training services
• Global customer base
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Engineering Consultancy
• Focused on Systems Engineering, Modelling and
Simulation
• Active in multiple industries
• Examples:
– Development and validation of models
– Analysis of systems using existing tools based on
Dymola, Simulink, etc.
– Development and integration of models with driving
simulators
• From desktop simulators to high performance full-motion
simulators in Formula 1 Indycar, and NASCAR
– Development of bespoke tools to support Systems
Engineering
• Translation of models between tools/languages
• Integration of models in to existing analysis tools and
processes
– Process development and improvement
• Requirements Management, Model Specification, Model
Management, etc.
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Modelica and FMI Development
• Engines Library
– Mean value and crank angle resolved engine models
• Powertrain Dynamics Library
– Powertrain modelling for driveability and shift quality
• Vehicle Dynamics for Motorsport
– Used in Formula 1, NASCAR, IndyCar and Sports cars
• Simulator Integration
– Integration of VDLMotorsports and rFactor Pro
• FlexBody Library
– Flexible bodies from Nastran, Genesis and Abaqus
• SystemID Library
– Neural networks for non-linear system identification of dynamic systems
• XML Reader
– Enables the use of XML files for parameters in Modelica
• FMI Blockset for Simulink
– Import FMI compliant models in to Simulink
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Software Portfolio
• Distributors of rFpro and Dassault Systemes solutions
Multi-domain modelling and simulation based on Modelica, supporting multiple physical
domains in a single integrated simulation environment
For managing requirements traceability and impact analysis across hardware and software
projects lifecycle
Design, validation and deployment of control system software using IEC 61131-3
languages for safety critical systems
A suite of design and functional tools to develop AUTOSAR compliant
embedded software
Specialist products within CATIA covering every aspect of Systems Engineering including
requirements, functional architecture, control design and physical modelling
rFactor Pro focuses on simulators for engineering development of vehicle dynamics and the
control systems and active safety systems that affect vehicle dynamics.
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Introduction
• Driving simulators increasingly used in both
Motorsport and Automotive
• Originally introduced in Motorsport for driver
training
• Allows tests to be completely safe and in
repeatable conditions
• Due to testing restrictions now used to evaluate
new designs, new technologies and work on car
setup before arriving at the race track
• Broad range of approaches to suit different
needs
– Desktop system
– Small motion systems with 3-4 dof
– Full motion platforms with 6 dof
• Entertainment systems
• Engineering development systems
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Example Motorsport System
• Simulators for engineering development
• Ansible Motion Series 1 platform
– 6 degrees of freedom
– Large excursions possible on all axes
– High frequency range for realistic motion
cueing
• rFactor Pro graphics, sound and track
data
– Low latency and high bandwidth offering
the fastest video & audio pipelines
– Extensive range of tracks available for
Motorsport and Automotive applications
• Dymola based vehicle dynamics model
– Multi-domain vehicle model
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Example Desktop System
• Able to evaluate baseline capability of a vehicle or enable detailed assessment of a control system
• Key features:
– rFactor Pro provides the core capability
• Range of test scenarios (race tracks, proving ground)
• High quality graphics
– Podium Technologies PTWinSim
• Host for the physics model enabling real-time telemetry
streaming
• Supports running multiple models from Dymola,
Simulink, C/C++
– Dymola vehicle model
• Full MultiBody chassis model
– Telemetry system
• Gredi used to view data in real-time from the model
– Logitech steering wheel and pedals (gaming system)
– 1 PC used for the complete system
• 1 for the simulator (graphics, physics, etc.)
• Optionally separate pc for calibration and telemetry tools
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Generalised architecture
• Driver interface
– Single LCD to multiple projectors
– Gaming wheel and pedals to sophisticated hand
wheel loading system
– Motion platform
• Graphics system
– Typically based on gaming technology such as
rFactor Pro but specially developed for DiL
• Physics model
– Appropriately detailed model of the car to be
tested
• Desktop system might be just 1 PC
• High-end driving simulator
– 8+ PC’s (1 per projector, 1 for physics, 1 for
motion, 1 for telemetry, 1 for overall coordination)
• Options to integrate HIL systems
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Dymola and CATIA Systems
• Dymola is a standalone tool
• CATIA Systems is integrated into the
3DEXPERIENCE platform
– Core functionality is the same, only the user
interface changes
– Easy to move models between the two programs
• Multi-domain modelling and simulation of
complex dynamic systems
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Component Orientated Modelling
• Modelling and simulation of systems integrating
multiple physical domains
– Mechanics (1D, MultiBody), 1D Thermofluids,
Control, Thermal, Electrical, Magnetics and more
• Promotes extensive model reuse at component
and system level
– Components represent physical parts: valves,
gears, motor
– Connections between parts describe the physical
connection (mechanical, electrical, thermal, signal,
etc.)
• Store your own component and system models
in libraries to easily share and reuse them
across the business
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Model Definition
• Models are defined using the Modelica modelling language
– A generic modelling language
– Design for convenient, component orientated modelling of complex multi-domain systems
– Models are defined as differential algebraic equations (DAE)
• Dymola provides access to the Modelica code behind models
model Inertia
extends Interfaces.Rigid;
parameter SI.Inertia J=1 “Moment of Inertia”;
SI.AngularVelocity w “Angular velocity”;
SI.AngularAcceleration a “Angular acceleration”;
equation
w = der(phi);
a = der(w);
flange_a.tau + flange_b.tau = J * a;
end Inertia;
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• A freely available, open source, standardised modelling language
• Developed and maintained by the Modelica Association
– An independent, international not-for-profit organisation
– Established in 1996
– Currently over 100 members from academia, tool vendors and industrial end-users
• Anyone can get involved
• Organised into project groups for the Modelica Language, Modelica Standard Library
and FMI Standard
• The Modelica Standard Library contains basic models in many engineering domains
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Modelling Approach
Example: Inverted Pendulum
• Classic problem in control and dynamics
– Representative of a missile flight control problem
• The centre of gravity is located behind the centre of
drag causing aerodynamic instability
• To design and tune the controller requires a model of
the system
• The systems contains the following:
– Mechanics in the cart and pendulum
– Electric motor to drive the cart
– Control system with sensors and actuators
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Modelling Approach
Traditional methodology
• Determine all the equations that capture the system
behaviour
• Manually rearrange and solve the equations
• Implement the solution in C, Fortran, Simulink, etc.
• Problems with this approach:
– Cannot easily change the properties of individual
components (mass, length, resistance, etc.)
– Cannot easily reuse the model or subsystem models for
other tasks
– Cannot easily change the detail in one part of the model
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Control
Modelling Approach
Modelica based approach
• Discretise the system into subsystems and
components
• Define the system architecture and physical
connections between subsystems
• Implement the subsystem models and plug these in to
the architecture
Electrical &
1D Mechanics
MultiBody
Mechanics
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Symbolic Manipulation
• The model equations are automatically transformed in to the required solution for simulation
• Advanced mathematical techniques are used to reduce the size of the problem without removing detail
• What does this mean in practice
• The Inverted Pendulum contains 659 equations
– Using the Modelica modelling approach these are formed as a DAE
• Symbolic manipulation automatically reduces this to:
– 7 continuous time states
– 92 other time varying quantities
• Including 1 linear system, originally containing 14 equations but reduced to a system containing just 2 equations
– All the other equations relate to constants or variables that are exactly equal to these 99 variables
• Advantages of Symbolic Manipulation
– Automate the often error prone process of rearranging equations in to a solution
– Apply advanced mathematical techniques to reduce the size of the problem
– Can deliver real-time simulation performance of Vehicle Dynamics models with over 100,000 equations (1ms
time step)
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Model Reuse
Benefits of the Modelica Approach
• Fast model creation through drag-and-drop of
components
• No manual rearrangement of model equations required
– Eliminates a difficult and tedious task
– Symbolic manipulation is used
• Models can easily be replaced with more detailed
representations
– Model architecture remains the same but new subsystem
models can be plugged in provided they have the same
physical connections
• Subsystems can easily be reused for different analysis
tasks
– For example, invert the physical model to determine the
control inputs required
– Here the angular response of the pendulum to a
disturbance is prescribed and the required input to the
power supply will be calculated
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Modelica Application Libraries
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Air Conditioning
Belts
Build Tools
eDrives
Engines
FlexBody
Flexible Bodies
Fuel Cell
Heat Exchanger
Human Comfort
Hydraulics
Liquid Cooling
Pneumatics
Powertrain Dynamics
Simulator
Smart Electric Drives
SystemID
Terrain Server
TIL Suite
Vapor Cycle
Vehicle Dynamics
VDLMotorsports
XMLReader
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Dymola in Motorsport
• Design
– Enables engineers to quickly evaluate the impact
of design changes on the complete system
– Offline and real-time simulation
• Test
– Use the models to support off-track testing
– DiL and HiL simulations
• Race
– Use the models trackside for setup optimisation
and with the telemetry system
– Integrate into lapsim and trackside tools
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Vehicle Dynamics for Motorsport
• VDLMotorsports Library
– Add-on to the standard Vehicle Dynamics library
– Used in Formula 1, IndyCar, GP2, NASCAR and
sports car racing
• Includes adjustable suspension
– Specify shim thickness to adjust track rod,
pushrod, etc.
• Kinematic and compliant suspension models
• Pacejka tyre model
• Wide range of experiments for K&C and
dynamics plus setup and quasi-static tests
• Real-time capable MultiBody models
• Open and extendible
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Simulator Toolbox
• Enables VDLMotorsports models to be compiled
ready to run with rFactor Pro
– Simply plug the vehicle model in to the template
and execute the build function
• Compiles model to work with PTWinSim and
McLaren Electronics vTAG
• Solution proven on several motion platforms
– Ansible Motion
– McLaren Electronics
– Moog
• Supports full range of rFactor Pro features
– HD Terrain Server and multiple tyre contact points
– Collisions
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Dymola Demo
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Summary
• Modelica and Dymola can be used to create MultiBody vehicle dynamics models suitable for use in
real-time applications
– Can also include mean value engine models and energy recovery systems to model the whole system
• Using Dymola, new design ideas and concepts can be quickly modelled and compiled for use in the
simulator
– Enables real drivers to start evaluating these ideas at a very early stage in the development process
– The simulator usage increases and is brought earlier in to the development process
Copyright © Claytex Services Limited 2015
Contact
For further information please contact:
Mike Dempsey
Claytex Services Ltd.
Edmund House
Rugby Road
Leamington Spa
CV32 6EL
UK
Tel +44 1926 885900
Fax +44 1926 885910
[email protected]
Copyright © Claytex Services Limited 2015