Simulated EV Dynamics: Safety & eTVC -...

ARTEMIS Pollux Project

Simulated EV Dynamics: Safety & eTVC

26.09.11

ARTEMIS POLLUX Project Process Oriented eLectronic controL Units for Electric Vehicles Developed on a Multi-System Real-Time Embedded Platform

Dr. Stephen Jones et. al., AVL List GmbH [email protected] +43 316 787 4484


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


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



Introduction






4

ARTEMIS Pollux Project 5

AVL CRUISE CarMaker

Matlab Simulink®

AVL CAMEO

Development of appropriate simulation tools for application

Integration of tools by defining & setting-up correct interfaces

Enhanced MiL platform

Co-Simulation Toolchain


Overview of Pollux Project 2012 Content

Introduction






6


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


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

8

1. Failure starts

2. Vehicle diverts outwards

3. Vehicle diverts inwards

4. Vehicle runs out of lane


E-Machine Failure Analysis Simulation Result #1

9

0 10 20 30 40-100

0

100

200

300

400

500

Time [s]

Driver

ste

er

an

gle

[de

g]

0 10 20 30 40

0

0.2

0.4

0.6

0.8

1

Time [s]

Gas p

ed

al [-

]

0 10 20 30 40-3

-2

-1

0

1

2

3

Time [s]

Veh

icle

late

ral de

via

tio

n [m

]

0 10 20 30 400

20

40

60

80

100

120

Time [s]

Veh

icle

sp

eed

[km

/h]

Reference (normal)

FL EM failure (full pos torque)

Comparison of one EM failure vs. Normal

0 10 20 30 40-10

0

10

20

30

40

Time [s]

FL E

M torq

ue

[N

m]

0 10 20 30 40-10

0

10

20

30

40

Time [s]

FR

EM

torq

ue

[N

m]

0 10 20 30 40-10

0

10

20

30

40

Time [s]

RL E

M torq

ue

[N

m]

0 10 20 30 40-10

0

10

20

30

40

Time [s]

RR

EM

torq

ue

[N

m]

Reference (normal)

FL EM failure (full pos torque)

Comparison of one EM failure vs. Normal

E-machine fails with full positive torque Driver

responds

Driver responds

Vehicle swings left and right


E-Machine Failure Simulation Results of Fiat Punto

10

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 Dry Full negative torque Uncontrollable Circling R=110m 100km/h Dry 2 Rear EM Full negative torque Uncontrollable Circling R=110m 70km/h Wet Full positive torque Uncontrollable 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 driver reaction time 2s

Dry Full positive torque Uncontrollable 2.8m lateral offtrack

outside of driving lane


Dry Zero torque Controllable


Dry Full negative torque Uncontrollable outside of driving lane


Dry 2 Rear EM Full negative torque Controllable 1.2m lateral offtrack

Based on these results, the hazard and risk assessment can be evaluated



Introduction






11


eTVC Targets

12

Agility Improve relation between steering and vehicle reaction

Performance Increase max lateral acceleration

Safety Increase vehicle stability and controllability

Stability / Safety


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.

13

TC

1

TqTra

TM

TCP

INIF

HMI

TT

TqSplit

TCP TT

TqMon

TT

INIF

HMI

SYS

TMO

TqLim

PTC

INIF

TCPPwrTqCnvr

INIF

EM

PTC

SYS

4

EM

3

INIF

2

HMI

1E-Torque Vectoring

Software (AVL)

eTorque Vectoring Controller

TqMotReq

YawRateRef

YawTqRef

Reference Value Calculation

Torque Vectoring Observer

Torque-Controller

Torque Split Optimization

Functional Architecture eTVC prototype

Schematic Diagram of 4-EM EV with eTVC


eTVC Simulation Environment

14

CarMaker for Simulink (v3.5.2)Vehicle Dynamics(Main Simulation Environment)

AVL CRUISE (v2010.1)Powertrain

Matlab/Simulink (R2007b)SW ofE-Torque Vectoring

Software development support

Algorithm verification

Model calibration

Function demo


eTVC Achievements

16

Performance Increase max lateral acceleration

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

50 60 70 80 90 100 1101

2

3

4

5

6

7

8

9

10

Steering wheel angle [deg]

Late

ral accele

ratio

n [m

/s2]

with eTV

w/o eTV

Comparison in skid pad testing (with vs. without eTV)

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

radius=50m


eTVC Achievements

17

Safety Increase vehicle stability

Increased speed in slalom maneuver

Max vehicle speed to drive through is found out with several trials


eTVC Achievements

18

Safety Increase vehicle stability and controllability

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

with eTVC (blue), w/o eTVC (grey) same speed



Introduction






19



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


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



Introduction






22



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 co-simulation 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

Simulated EV Dynamics: Safety & eTVC -...

Documents

Transcript of Simulated EV Dynamics: Safety & eTVC -...