politecnicotorino semiactivesusp 18gen08 rev03

Turin, January 18, 2008 Mod. 25-P02-00

Semi-Active Suspension

Control system development process

Michele Ieluzzi

Vehicle Systems – Active Systems

Head of Suspension Control System unit

Semi-Active Suspension 2January 18, 2008

Public

This document contains information which in proprietary to CRF. Neither this document nor the information contained herein shall be used, duplicated nor communicated by any means to any third part, in whole or in party, except with the prior written consent CRF.

Semi-Active Suspension development process

Simplify

Vehicle models

Simplify

Vehicle models

Control System

develop. environment

Control System


Handling/Comfort

Vehicle models

Handling/Comfort

Vehicle models

Four poster

test bench tuning

Road tests

Adaptive control strategy tuning

(Lateral & Longitudinal dynamic)

Modal damping gain tuning

Development

Vehicle

Technology Gate

• Vehicle assessment and fine tuning

• Experimental Control development

Actuator SpecificActuator Specific

ECU requirementsECU requirements

Control SW spec.Control SW spec.

DEMONSTRATOR EXPERIMENTAL DEVELOPMENT

SOFTWARE “IN THE LOOP” APPROACH

“Rapid prototype”code generation

• Control gain optimisation• Control Analysis and development• ECU control sw development & debug

Control Development


Public


Damper velocities

Actuators

Model

Sensor signals Damper forces

Control output

Vehicle model output,states,etc.

Driver Input

2 2

d 2z ACC2

2 1

d 2z ACC1

20

Fa 4

19

Fa 3

18

F a2

17

F a1

1 6

F zterra 4

1 5

F zterra 3

14

F zte rra 2

13

F zterra 1

12

d 2z w4

11

d 2z w3

10

d 2 zw2

9

d 2 zw1

8

dx 4

7

dx 3

6

d x2

5

d x1

4

x4

3

x3

2

x2

1

x1

d zc4

F ba rra 4

d zst 4

F j 4

F zc4

x4

d x4

d2zw 4

F zt er ra4

F a4

C orn er 4

dzc3

Fb arra3

dzst 3

Fj 3

F zc3

x3

d x3

d2zw 3

F zt er ra3

F a3

C orn er 3

d zc2

F barra2

d zst 2

F j2

F zc2

x2

dx2

d2 zw2

Fzt er ra2

F a2

C o rn e r 2

dzc1

Fba rra 1

dzst 1

Fj 1

Fzc 1

x 1

dx 1

d 2zw 1

F zte r ra 1

Fa 1

C o rne r 1

0

C on st a nt 3

0

Co n st an t 2

0

C on st an t 1

0

Co n st an t

F zc1

F zc2

F zc3

F zc4

F ve rt

Mx

My

dzc1

dzc2

dzc3

dzc4

d 2zA C C1

d 2zA C C2

B o dy

x3

x4

F barra3

F barra4

B arra p ost e r i ore

x1

x2

Fba rra 1

Fba rra 2

Ba rra a nt e r io re

7

M y

6

M x

5

F ve r t

4

d zst 4

3

dz st3

2

dz st2

1

dz st1

Vehicle Model

Control

Road input

Control Parameters

“Software in the loop” approach

22

d2 zACC2

21

d2 zACC1

20

F a4

19

F a3

18

F a2

17

F a1

1 6

Fz te rra4

1 5

Fz te rra3

1 4

F zterra2

1 3

Fz te rra1

12

d 2 zw4

11

d 2 zw3

10

d 2 zw2

9

d 2 zw1

8

dx 4

7

dx 3

6

d x2

5

dx 1

4

x4

3

x3

2

x2

1

x1

dzc4

Fba rra 4

dzst 4

Fj 4

Fzc 4

x4

dx4

d 2zw4

Fz te rra4

Fa4

Corn er 4

dzc 3

Fb arra3

dzs t3

Fj 3

Fzc 3

x3

dx3

d 2zw3

Fz te rra3

Fa3

Co rne r 3

d zc2

F barra2

d zst 2

F j2

F zc2

x2

d x2

d2zw2

F zt erra2

F a2

Corn er 2

dzc1

Fba rra 1

dzst 1

Fj 1

F zc1

x1

dx1

d2 zw1

Fzt erra1

F a1

Co rne r 1

0

Con st an t3

0

Co nst a nt 2

0

Co nst a nt 1

0

Co nst a nt

Fzc 1

Fzc 2

Fzc 3

Fzc 4

Fv ert

Mx

My

dzc1

dzc2

dzc3

dzc4

d 2zA CC1

d 2zA CC2

Bo d y

x 3

x 4

F barra3

F barra4

B arra p ost e ri o re

x1

x2

Fba rra 1

Fba rra 2

Ba rra a nt er i o re

7

My

6

Mx

5

F ve rt

4

dz st4

3

d zst 3

2

d zst 2

1

d zst 1

• Virtual assessment and fine tuning

• Actuators specification

• Control gain optimisation

• Control Analysis and development

• ECU control sw development & debug

Actuatorscharacteristics

Virtual vehicle & control system behaviour

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15

0.00

0.01

0.02

0.03

0.04

0.05

Ac

c[g

]

Frequency [Hz]

Random input: comfort (60 km/h)

Seat guide verticalacceleration

Passive

Semi Active

Full vehicle

MB model

MATLAB/Simulink Model 10 D.o.F.


Public


MATLAB/Simulink Model 10 D.o.F.

Model components

(D.o.F.):

� Car-body (3)

� Heave

� Roll

� Pitch

� Engine (3)

� Heave

� Roll

� Pitch

� Wheels (4)

� Heave

Fzc → suspension force at vehicle corner

K C Passive suspension:

F = - K·X - C·X.

Simplified vehicle model structure

Fzc3

Fzc4

Hf

Z

X

G

3

Fzc1

Rf

Car-Body

Pf

X

Y Z

G

R fHf

P f

Engine

4

1

2

Fzc2Y


Public


Simplified vehicle model validation (example)

Vehicle model 10 d.o.f.

Model validation on the basis of 4 poster bench tests

FL Vert. Acc. FR Vert. Acc.

RL Vert. Acc. RR Vert. Acc.

Comfort track – 60 km/h

Sine-hole passing – 80 km/h

Experimental Model

FL Vert. Acc. FR Vert. Acc.

RL Vert. Acc. RR Vert. Acc.


Public


Damper velocities

Actuators

Model

Sensor signals Damper forces

Control output


Driver Input

2 2

d2 zACC 2

2 1

d2 zACC 1

20

Fa4

19

Fa3

18

F a2

17

F a1

16

Fzt er r a4

15

Fzt er r a3

14

F zte rr a2

13

F zte rr a1

12

d2zw 4

11

d2zw 3

10

d2z w2

9

d2z w1

8

d x4

7

d x3

6

dx2

5

dx1

4

x4

3

x3

2

x2

1

x1

dzc4

Fbar ra4

dzst4

Fj4

Fzc4

x4

dx4

d2zw4

Fzt err a4

Fa4

Cor ner 4

dzc3

Fbar ra3

dzst3

Fj3

Fzc3

x3

dx3

d2zw3

Fzt err a3

Fa3

C or ner 3

dzc2

Fbar ra 2

dzst2

Fj 2

Fzc2

x2

dx2

d2zw2

Fzt er ra2

Fa2

C or ner 2

dzc1

Fbar ra 1

dzst1

Fj 1

Fzc1

x1

dx1

d2zw1

F zt er ra1

Fa1

Cor ner 1

0

C onsta nt 3

0

C onsta nt 2

0

C onst ant 1

0

Co nsta nt

F zc1

F zc2

F zc3

F zc4

F vert

M x

M y

dzc1

dzc2

dzc3

dzc4

d2zACC 1

d2zACC 2

Body

x3

x4

Fbar ra3

Fbar ra4

B ar ra post er io re

x1

x2

Fbar r a1

Fbar r a2

Ba rr a ant er ior e

7

M y

6

M x

5

Fve rt

4

d zst 4

3

d zst 3

2

dzst2

1

dzst1

Vehicle Model

Control

Road input

Control Parameters

if (x>0)

….

elseControl software specification

ECU requirements specification

Sensors specification

Actuators specifications

Technology Gate

• Virtual assessment and fine tuning

• Actuators specification

• Control gain optimisation

• Control Analysis and development

• ECU control sw development & debug

System Architecture & Component Specification


Public


Semi-active suspension system architecture

MM-ECU

CAN bus

Frontactuators

Rearactuators

Front right body

acceleration

Rear right body

acceleration

Front left body

acceleration

Front right wheel

acceleration

Front left wheel

acceleration


Public


Suspension damping control architecture

Lateral Dynamics

Longitudinal Dynamics

Hole-passing control

Vertical Dynamics (Skyhook)

Current

manager


Public


Single-corner passive suspension model

M = sprung mass x = suspension travel xst = road input Ktyre = tyre stiffness

m = unsprung mass xM = suspended mass pos. K = suspension stiffness

F = suspension force xw = non-suspended mass pos. C = suspension damping ratio

M

mxw

xst

xM

x

F

F

Ktyre

Passive suspension:

K C

F = - K·x - C·x.

MxM - F = 0..

mxw + F - Ktyre(xst - xw)= 0..

MxM + K·x + C ·x = 0..

mxw - K·x - C ·x - Ktyre(xst - xw)= 0..

.

.

• Equations of motion:

• The system has 2 D.o.F. (4 states) and two natural

frequencies:

ω1 =

K·Ktyre

M·(K+Ktyre)

C

2·M

-

2

K

M≅

ω2 =

(K+Ktyre)

m

Ktyre

m≅

(1)

(2)


Public


Semi-active control law (Sky-hook )

Controlled suspension:

(Sky-hook control law) 2 tuning parameters

Fdamp = Cabs ·xM + Crel ·x. .

Cabs ; Crel

Semi-active strategy:

(Continuous control) (NO hydraulic energy supply)

Fdamp = Cabs ·xM + Crel ·x. .

if Fdamp ·x > 0.

Fdamp ·x ≤ 0.

Fdamp = 0 if

XM

·

X·

X·

XM

·

Fdamp

NO

NO YES

YES

VREL [m/s]

F [N]

Working area of a semi-active damper

Virtual ’’Skyhook’’ damper

ON-OFF ’’Skyhook’’ strategy

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15

0.00

0.01

0.02

0.03

0.04

0.05

Ac

c[g

]

Frequency [Hz]


Seat guide vertical

acceleration

Passive

Semi Active


Public


Gain THETA-DVOL [ ]

frequency [Hz]

0

0.02

0.04

0.06

0.08

0.1

0 0.5 1 1.5 2 2.5 3 3.5

Passive

Semi Active

Virtual system behaviour optimisation

Vertical dynamics: DOE simulation plan to optimise SkyhookModal gain on different test track • Random track at different speed

- comfort track- pavè

- highway

• Sine hole passing at different speed

5.0

5.5

6.0

6.5

7.0

7.5

Ico Ivc

PASSIVE

SEMI-ACTIVE

Roll motion & roll velocity Index

Lateral dynamics: control gain optimisation result

Gain THETA-AY [deg/g ]

Frequency [Hz]

2

3

4

5

6

7

8

9

0 0.5 1 1.5 2 2.5 3 3.5

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15

0.00

0.01

0.02

0.03

0.04

0.05

Ac

c[g

]

Frequency [Hz]


Seat guide verticalacceleration

Passive

Semi Active

0 2 4 6 8 10 12 14 160

0.01

0.02

0.03

0.04

0.05

0.06

0.07

Frequency [Hz]

Acc

Highway 100 km/h

Passive

Semi Active

Sweep at 100 km/h

Uneven road at

60 km/h


Public


Semi-active Suspension Prototype Development

Simplify

Vehicle models

Control System


Control System


Handling/Comfort

Vehicle models

Four poster

test bench tuning

Four poster

test bench tuning

Road tests



Road tests



Technologydemonstrator

Technologydemonstrator

Modal damping gain tuning

Development

Vehicle

Development

Vehicle

Technology Gate

• Vehicle assessment and fine tuning

• Experimental Control development

Actuator SpecificActuator Specific

ECU requirementsECU requirements

Control SW spec.Control SW spec.

DEMONSTRATOR EXPERIMENTAL DEVELOPMENT

SOFTWARE “IN THE LOOP” APPROACH

“Rapid prototype”code generation

• Control gain optimisation• Control Analysis and development• ECU control sw development & debug

Control Development


Public


Rapid prototyping Control application

Damper velocities

Actuators

Model

Sensor signalsDamper forces

Control output


Driver Input

2 2

d2zA C C2

2 1

d2zA C C1

20

Fa 4

19

Fa 3

18

F a2

17

F a1

1 6

Fzt er ra4

1 5

Fzt er ra3

14

Fzt er ra2

13

Fzt er ra 1

12

d2zw 4

11

d2zw 3

10

d2 zw2

9

d2 zw1

8

dx4

7

dx3

6

d x2

5

d x1

4

x4

3

x3

2

x2

1

x1

dzc4

F barr a4

dzst 4

F j4

F zc 4

x4

dx 4

d2zw4

F zt er ra 4

Fa4

C orne r 4

dzc3

F barr a3

dzst 3

F j3

F zc 3

x3

dx 3

d2zw3

F zt er ra 3

Fa3

C orner 3

d zc 2

F bar ra2

d zs t2

F j2

F zc2

x2

d x2

d2zw 2

F zter r a2

F a2

C orner 2

dzc1

Fbar ra1

dzst1

Fj1

F zc1

x1

dx1

d2 zw 1

F zter r a1

F a1

C orner 1

0

Co nsta nt 3

0

Co nsta nt 2

0

C onst ant 1

0

Con sta nt

Fzc1

Fzc2

Fzc3

Fzc4

Fv ert

M x

M y

dzc1

dzc2

dzc3

dzc4

d2 zA CC 1

d2 zA CC 2

Bo dy

x3

x4

Fbar ra 3

Fbar ra 4

Ba rra po st er i ore

x1

x2

Fbar r a1

Fbar r a2

B ar ra ant er io re

7

My

6

Mx

5

F ver t

4

d zst 4

3

dzst 3

2

d zst2

1

d zst1

Vehicle Model

Control

Road input

Control Parameters

Automatic Control

Code generation

(RTW)

“Rapid prototyping”

Control ECU

dSPACE MicroAutoBox

RTI 1401 blocksetRTI CAN blockset

ECU I/O management blockset

Virtual environment Control algorithm in MATLAB/Simulink

I/O managersI/O managers

ControlControl


Public


Control parameters calibration interface

Lateral dynamic

control

Longitudinal dynamiccontrol

Vertical dynamic

control

Hole-passing strategycontrol


Public


Relative damping gains

15 16 17 18 19

22 23 24 25 26

29 30 31 32 33

36 37 38 39 40

43 44 45 46 47

Sk

yh

oo

k d

am

pin

g g

ain

s

1 2 3 4 5

8 9 10 11 12

6 7

13 14

20 21

27 28

34 35

41 42

48 49

Virtual environment

0 5 10 15 20 25 300

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

Acc [m

/s2]

0 0 .5 1 1. 5-3

-2

-1

0

1

2

3

4

5

Passive

Semi-active

Base configuration

Four poster test bench: definition of DOE analysis


22 23 24 25

29 30 31 32

36 37 38 39

Skyh

oo

k d

am

pin

g g

ain

s

15 16 17 18

0.45 0.59 0.77

1.0

1.3

1.0

0.7

7

0.5

9

DOE on four poster test bench


Public


Virtual analysis optimisation

DOE experimental plan (over all the mission panel)

6-7

5-6

4-5

3-4

2-3

1-2

0-136 393837

313029 32

242322 25

17 181615

∆∆∆∆RMS Az (seat guide vertical acceleration )

(improvement vs passive [%])

Highway

Mission panel:

• Random track

- comfort track

- pavé

- highway

• Sine hole passing

Modal damping gainsModal damping gains

Four poster test bench: modal damping gain tuning


22 23 24 25

29 30 31 32

36 37 38 39

Sk

yh

oo

k d

am

pin

g g

ain

s

15 16 17 18


Public


Example of control effect (bench test): vertical dynamics

Sine hole passing: (speed = 80 Km/h)

Seat guide vertical acceleration

Acc [

m/s

^2]

Time [sec]

Passive

Controlled

Comfort Track (speed = 60km/h)


Acc [

m/s

^2]

Freq [Hz]

Passive

Controlled

Damper working area

Vel [m/s]

Fo

rce [

N]


Public


Example of control effect (road test): vertical dynamics

Comfort track @ 80 km/h

RMS RMF Moto cassa

7%

6%

15% Passive

Controlled

Body movement


ac

c[m

/s2]

RMS of Pitch & Roll body acceleration

RMS Pitch RMS Roll

6%

Passive

Controlled

Average on different testsa

cc

[de

g/s

2]


Public


Example of control effect (road test): lateral dynamics

Roll motion and velocity quality index

ICO = Quality index of roll motion

IVC = Quality index of roll velocity

Steering angle

Lateral acceleration

Roll angle

Passive

Controlled

ICO IVC

Passive

Controlled

Best

Worst

ISO lane change @ 90km/h


Public


Gear shift @ 100% gas pedal

Example of control effect (road test): longitudinal dynamics

Cambio marcia 1-2

Max picco-picco

Passiva

Controllata

Cambio marcia 2-3

Max picco-picco

ve

l[d

eg

/s]

Passiva

Passive

Controlled

Input driver

Passive

Controlled

66%

57%

Passive

Controlled

Gear shift 1-2

Peak-to-peak

Average on different tests

64% 5

3%

Gear shift 2-3

Peak-to-peak

ve

l[d

eg

/s]

Gear

Pitch Angle

Pitch Velocity


Public


Ferrari 575 Maranello

[2003]Lancia Thesis 2.4jtd 20v CAE

[2004]

Fiat Stilo 2.4 20v Abarth Seelespeed

[2001-2004]

Systems developed

Iveco StralisS.A. Cab Suspension

[2003-2005]

Alfa Brera 3.2 4WD

SDC

[2005-2006]

Iveco Eurostar

S.A. Suspension[2001-2003]

HST

S.A. Lateral Suspension

[2000-2002]

politecnicotorino semiactivesusp 18gen08 rev03

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