Simulated EV Dynamics: Safety & etvc

Transcription

1 Simulated EV Dynamics: Safety & etvc Dr. Stephen Jones et. al., AVL List GmbH ARTEMIS ARTEMIS Pollux POLLUX Project Project Process Oriented electronic control Units for Electric Vehicles Developed on a Multi-System Real-Time Embedded Platform

2 Simulated EV Dynamics Content Introduction Co-Simulation Toolchain of CRUISE & CarMaker E-Machine Failure Analysis in Simulation E-Torque Vectoring Control (etvc) Effect of etvc on E-Machine Failure Summary & Next Steps 2

3 Introduction Pure battery Electric Vehicle with 4 e-machines to drive 4 wheels independently. AVL works on the toolchain development of 1D powertrain tool (AVL CRUISE) with 3D vehicle lateral dynamics simulation tool (IPG CarMaker). Hazard and Risk Assessment of e-machine failure with simulation analysis. Development and validation of e-torque Vectoring control software. 3

4 Simulated EV Dynamics Content Introduction Co-Simulation Toolchain of CRUISE & CarMaker E-Machine Failure Analysis in Simulation E-Torque Vectoring Control (etvc) Effect of etvc on E-Machine Failure Summary & Next Steps 4

5 Co-Simulation Toolchain Development of appropriate simulation tools for application Integration of tools by defining & setting-up correct interfaces Enhanced MiL platform AVL CAMEO Matlab Simulink AVL CRUISE CarMaker 5

6 Overview of Pollux Project 2012 Content Introduction Co-Simulation Toolchain of CRUISE & CarMaker E-Machine Failure Analysis in Simulation E-Torque Vectoring Control (etvc) Effect of etvc on E-Machine Failure Summary & Next Steps 6

7 E-Machine Failure Analysis A series of simulation run in the toolchain with certain e- machine failures. Safety simulation for ISO26262 and virtual Hazard Severity Rating in early concept phase. 7

8 E-Machine Failure Analysis Simulation Result #1 Single e-machine (front left) fails with full positive torque while running in a circle, speed=70km/h, radius=110m, wet asphalt road µ=0.4 Fiat Punto EV, 800kg, 4 e-machines with 12.5kW each Two vehicles in video Grey colour car: Reference without EM failure Blue colour car: With single EM failure 1. Failure starts 2. Vehicle diverts outwards 3. Vehicle diverts inwards 4. Vehicle runs out of lane 8

9 RL EM torque [Nm] RR EM torque [Nm] Vehicle lateral deviation [m] Vehicle speed [km/h] FL EM torque [Nm] FR EM torque [Nm] Driver steer angle [deg] Gas pedal [-] E-Machine Failure Analysis Simulation Result # Time [s] E-machine fails with full positive torque Comparison of one EM failure vs. Normal Time [s] Driver responds Time [s] Driver responds Comparison of one EM failure vs. Normal Time [s] Reference (normal) FL EM failure (full pos torque) Reference (normal) FL EM failure (full pos torque) Time [s] Time [s] Time [s] Time [s] Vehicle swings left and right 9

10 E-Machine Failure Simulation Results of Fiat Punto Driving scenario Road Friction (Dry µ=0.8, Wet µ=0.4) Full positive, Zero, Full Negative torque failure Controllablility Comments Straight 100km/h Dry Full positive torque Controllable 0.7m lateral offtrack Straight 100km/h Dry Zero torque Controllable Straight 100km/h Dry Full negative torque Controllable 1.0m lateral offtrack Straight 100km/h Dry 2 Rear EM Full negative torque Controllable Straight 100km/h Wet Full positive torque Controllable 0.7m lateral offtrack Straight 100km/h Wet Zero torque Controllable Straight 100km/h Wet Full negative torque Controllable Straight 100km/h Wet 2 Rear EM Full negative torque Controllable 1.0m lateral offtrack Circling R=110m 100km/h Dry Full positive torque Uncontrollable Circling R=110m 100km/h Dry Zero torque Controllable Circling R=110m 100km/h Based on Dry these results, Full negative torque the hazard Uncontrollable and risk Circling R=110m 100km/h Dry 2 Rear EM Full negative torque Uncontrollable Circling R=110m 70km/h Wet Full positive torque Uncontrollable assessment can be evaluated Circling R=110m 70km/h Wet Zero torque Controllable Circling R=110m 70km/h Wet Full negative torque Uncontrollable Circling R=110m 70km/h Wet 2 Rear EM Full negative torque Uncontrollable vehicle spinning Circling R=110m 70km/h Dry Full positive torque Controllable with reduced speed Circling R=110m 70km/h Dry Zero torque Controllable with reduced speed Circling R=110m 70km/h Dry Full negative torque Controllable with reduced speed Circling R=110m 70km/h Dry 2 Rear EM Full negative torque Controllable with reduced speed Circling R=110m 70km/h 2.8m lateral offtrack Dry Full positive torque Uncontrollable driver reaction time 2s outside of driving lane Circling R=110m 70km/h driver reaction time 2s Dry Zero torque Controllable Circling R=110m 70km/h driver reaction time 2s Dry Full negative torque Uncontrollable outside of driving lane Circling R=110m 70km/h driver reaction time 2s Dry 2 Rear EM Full negative torque Controllable 1.2m lateral offtrack 10

11 Simulated EV Dynamics Content Introduction Co-Simulation Toolchain of CRUISE & CarMaker E-Machine Failure Analysis in Simulation E-Torque Vectoring Control (etvc) Effect of etvc on E-Machine Failure Summary & Next Steps 11

12 etvc Targets Agility Improve relation between steering and vehicle reaction Performance Increase max lateral acceleration Safety Increase vehicle stability and controllability Stability / Safety 12

13 2 INIF 3 EM 1 E-Torque HMI 4 SYS INIF EM PwrTqCnvr PTC PTC INIF TqLim TCP TCP TqSplit TT TM TCP INIF HMI TqTra TT TT INIF HMI SYS TqMon TMO 1 TC etvc Concept Principles etvc = E-Torque Vectoring Control, for each & every wheel. Model matching technique is used to generate a yaw moment demand to meet driver s pedal and steering inputs. The yaw moment demand is met by optimally splitting torques among the 4 individual e-machines. etorque Vectoring Controller Vectoring Software (AVL) Torque Vectoring Observer Reference Value Calculation YawRateRef Torque- Controller YawTqRef Torque Split Optimization TqMotReq Schematic Diagram of 4-EM EV with etvc Functional Architecture etvc prototype 13

14 etvc Simulation Environment Software development support CarMaker for Simulink (v3.5.2) Vehicle Dynamics (Main Simulation Environment) Algorithm verification Model calibration Matlab/Simulink (R2007b) SW of E-Torque Vectoring AVL CRUISE (v2010.1) Powertrain Function demo 14

15 Lateral acceleration [m/s 2 ] etvc Achievements Performance Increase max lateral acceleration 10 9 Skid pad testing is simulated to test the vehicle handling characterises and grip limit The vehicle is slowly accelerated until the vehicle leaves the circular track Comparison in skid pad testing (with vs. without etv) radius=50m with etv w/o etv Steering wheel angle [deg] Vehicle with etvc can reach higher maximum lateral acceleration The handling of the vehicle is changed from under steering without etvc to near neutral steering with etvc 16

16 etvc Achievements Safety Increase vehicle stability Increased speed in slalom maneuver Max vehicle speed to drive through is found out with several trials 17

17 etvc Achievements Safety Increase vehicle stability and controllability with etvc (blue), w/o etvc (grey) same speed With etvc, the driver can drive the vehicle through the slalom manoeuvre at speed 49km/h, whilst the vehicle can t without etvc at 49km/h 18

18 Simulated EV Dynamics Content Introduction Co-Simulation Toolchain of CRUISE & CarMaker E-Machine Failure Analysis in Simulation E-Torque Vectoring Control (etvc) Effect of etvc on E-Machine Failure Summary & Next Steps 19

19 Effect of etvc on E-Machine Failure E-torque vectoring controller demands torques of remaining functional e-machines to counteract the effect of e-machine failure. Significant potential benefits of e-torque vectoring on vehicle stability when one e-machine fails due to the e-machine itself or machine power electronics controller. 20

20 EM-failed vehicle With vs. W/O etvc Single e-machine (front left) fails with full negative torque while running in a circle, speed=100km/h, radius=110m, dry asphalt road µ=0.8 Fiat Punto EV, 800kg, 4 e-machines with 12.5kW each Two vehicles in video Grey colour car: Reference without etvc, with single EM failure Blue colour car: With etvc, with single EM failure 21

21 Simulated EV Dynamics Content Introduction Co-Simulation Toolchain of CRUISE & CarMaker E-Machine Failure Analysis in Simulation E-Torque Vectoring Control (etvc) Effect of etvc on E-Machine Failure Summary & Next Steps 22

22 Summary & Next Steps A co-simulation toolchain is built with AVL Cruise, InMotion, IPG CarMaker, and Matlab Simulink for EV with 4 e-machines. Safety simulation for ISO26262 and virtual hazard severity rating in early concept phase is demonstrated with the cosimulation toolchain. E-Torque Vectoring Controller is developed and validated in the simulation. Potential improvement of lateral vehicle dynamics and safety with etvc is demonstrated, not only on normal functioning EV, but also on vehicle with e-machine failure. Next Steps - migration to Real Time. 23