Real Time Simulation of Heavy Trucks using SIMPACK

Transkript

1 Real Time Simulation of Heavy Trucks using SIMPACK, FKFS SIMPACK User Meeting 2001 November 14, 2001, Bad Ischl / Austria Slide 1

2 Overview FKFS is a non-profit-making foundation, located in / Germany since 1930 close co-operation with University 120 employees in 2001 Automotive Industrial Research and Services Development Slide 2 Education of Automotive Engineers

3 Internal Combustion Engines Forschungsinstitut für Major Fields of Work Mechatronics and Software Slide 3

4 Overview Overview Introduction Using SIMPACK for Real Time Simulation RT Models of Truck / Trailer Vehicle Dynamics Application Example: Driving Simulator Application Example: Active Suspension Portability and HIL aspects Conclusion and Outlook Slide 4

5 requirements executable specification production code generation? Product application road test Scope of Regard software prototyping hardwarein-the-loop softwarein-the-loop manin-the-loop system integration Slide 5 software implementation development step testing method

6 Introduction Modelling and simulation objectives: Use of identical simulation models for offline and real time simulation Use of modern software tools with automatic code generation, no manual coding Integration of measured parameters into the simulation, e.g. tyre properties Portability of simulation models between different Real Time Hardware and Operating Systems!!! Slide 6

7 MATLAB / SIMULINK ASCET- -SD ETAS FKFS Tool Chain INTEC Coupling for Real Time Applications TTP-Plan TTP-Build CANULINK Slide 7

8 Real Time Interface SIMPACK - SIMULINK vehicle dynamics model Symbolic Code Interface - Interface code - C libraries - Target specific make files ANSI-C code MATLAB / SIMULINK Real Time Workshop (F77, F90, C) Automatic code modification tool Offline simulation in SIMULINK C-code target specific C compiler / linker EXE Slide 8 Executable program running on a real time computer

9 Real Time Capable Truck Models in SIMPACK Slide 9

10 Truck/Trailer Model Tractor / trailer model with rigid chassis 9 bodies, 28 DOF + 7 rheonomic drives sub-structure tractor Load movement (rheonomic ) sub-structure trailer Load movement (rheonomic ) fifth wheel Slide 10 elastic hitch, tow-bar with contact algorithm suspension: leaf or air springs, dampers, stabilisers externally calculated tyre forces (FKFS REAL TIRE model)

11 Semitrailer Train Model Semitrailer train model with rigid chassis 8 bodies, 29 DOF + 3 rheonomic drives load movement (rheonomic ) coupling gear (3 DOF) Slide 11

12 Truck model, 2 rear axles, elastic chassis, cab suspension 7 bodies, 20 DOF + 3 rheonomic drives load movement (rheonomic, 3 axes ) Complex Truck Model chassis torsion cab suspension (3 DOF) Slide 12

13 Structure of SIMULINK / SIMPACK vehicle models Forschungsinstitut für Integration of SIMPACK truck models in SIMULINK steering wheel torque tire forces driving resistance M_H F_R F_F measured tire behaviour and steering kinematics FKFS REAL TIRE tires and steering aero-dynamics delta_h X_V_R v_veh steering angle tire print movement vehicle motion Drv driver input Driver M_PT F_F F_R M_PT embedded SIMPACK MBS v_veh X_V_R power train vehicle dynamics Slide 13 delta_h driver

14 SIMPACK/SIMULINK Truck model execution times on Industrial PC based Real Time Computers (single processor) Model Type DOF/ Rheo ODE Solver Min. Step Size on IPC (AMD Athlon 1000 MHz) 28/7 1.6 ms Real Time Performance 29/3 20/3 Runge- Kutta 2 nd order (Heun) 1.7 ms 1.4 ms Slide 14 35/7 AMD Athlon 1800+, expected: 1.8 ms

15 Application example: Real Time Driving Simulator Slide 15

16 FKFS Lab Driving Simulator Powertrain and vehicle dynamics simulation Investigation of steer-by -wire concepts interactive software testing (e.g vehicle dynamics control) Real Time Computer with vehicle model 3D graphics Application example: Real Time Driving Simulator Slide 16 Pedals Gear shift lever Steering unit Parameter variation Instrument panel

17 FKFS Lab Driving Simulator: Active Steering Unit Steering torque up to 16 Nm, dynamics: < 20 ms Sensors for steering angle and speed 3 phase servo motor for torque generation interface to real time simulation computers Tire and steering simulation model Application example: Real Time Driving Simulator steering wheel resolver steering speed steering torque servo motor steering angle Slide 17 steering column limiter belt drive

18 Application example: Real Time Driving Simulator Slide 18

19 Real time implementation of a software prototype Test of active suspension components using a test bench connected to a Real Time vehicle model Controller Software (ASCET SD) Application Example: Active Suspension prototyping code generation ECU Prototype actuator signals sensor signals test bench with active suspension actuator real time link measurements test bench control Slide 19 vehicle dynamics and powertrain model (SIMPACK / SIMULINK) FKFS Real Time Integration Package real time computer with complete vehicle model

20 Kinematic loops and elasticities in Real Time Simulation Forschungsinstitut für 1,20E-01 1,00E-01 2,00E-02 8,00E-02 0,00E+00-2,00E-01-1,50E-01-1,00E-01 6,00E-02-5,00E-02 0,00E+00 5,00E-02 1,00E-01 1,50E-01 2,00E- -2,00E-02 3,00E-01 4,00E-02-4,00E-02 2,00E-01 2,00E-02-6,00E-02 Application Example: Active Suspension 0,00E+00-2,00E-01-1,50E-01-1,00E-01-5,00E-02 0,00E+00 5,00E-02-8,00E-02 1,00E-01 1,50E-01 2,00E-01-2,00E-02 0,00E+00-2,00E-01-1,50E-01-1,00E-01 SIMPACK -1,00E-01-5,00E-02 0,00E+00 5,00E-02 1,00E-01 1,50E-01 2,00E-01-1,20E-01-1,40E-01 SIMPACK Input Functions 1,00E-01-1,00E-01-2,00E-01-3,00E-01 USER Routines Special Real Time User Routines kinematic and elastokinematic wheel suspension systems steering transmission incl. steering elasticity Slide 20 -> no kinematic loops, full precision, integration speed up,...

21 FKFS Universal Measuring Vehicle for Tire Properties Forschungsinstitut für Measurement of Tire Properties on Real Roads measuring wheel Slide 21 Lateral force vs. slip angle and wheel load Lateral force stiffness vs. camber angle / wheel load

22 Portability Portability issues: Transformation of SIMPACK Symbolic Code to pure ANSI-C enables porting of combined SIMPACK/ SIMULINK models to different Real Time hardware and Real Time operating systems Portability tested on: Industrial PC System (XPC Target RT kernel) VME / Power PC computer (Lynx OS) dspace DSP/alpha combo (reduced model complexity) Porting to any other platform is possible if computing power and memory are sufficient Embedded SIMPACK RT models are also fully functional in offline simulation with MATLAB/SIMULINK (running under MS Windows) Slide 22

23 Conclusion and Outlook Conclusion Since 1999 SIMPACK is used at FKFS for creation of real time capable vehicle dynamics models Embedding of SIMPACK into SIMULINK expands modelling techniques to a wider range Driving simulator and Hardware-in-the-Loop applications for trucks and passenger cars have been realized using SIMPACK combined with SIMULINK Code efficiency is sufficient to run complex SIMPACK models in Real Time on single processor hardware Further Activities Advanced modelling of elastic suspension parts for Real Time Simulation Realization of a Hardware-in-the-Loop simulator for truck vehicle dynamics control ( ESP ) Slide 23

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