Chapter 5 Modelling und Simulation of vehicles 5.1 ... · McPherson suspension strut Five point...

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Chapter 5 Modelling und Simulation of vehicles

5.1 Modeling a vehicle

5.2 Simulation of vehicles

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5.1 Modellierung eines Kraftfahrzeuges

Fahrzeug als mechatronisches Gesamtsystem

Arbeitsgebiete:

• Aktorik• Elektronik• Sensorik• Fahrdynamik• Hydraulik• Konstruktion• Mikrosystemtechnik• Modellbildung• Simulation• Reglerentwurf

• Aktive Fahrwerke• Elektronikkomponenten

• Fahrwerkskomponenten• Komfortsysteme∗ ACC

• Regleralgorithmen• Passive Sicherheit,

Rückhaltesysteme• Sensoren

• Aktive Sicherheit∗ ABS, TCS, ESP

Aufgabenstellung am Fahrzeug:

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5.1 Modelling a vehicle

Areas ofResearch:

• actuators• Electronics• Sensors• vehicle dynamics• hydraulics• mechanical design• microsystems• modelling• controller design• simulation

• active suspension• electronic components

• suspension components• comfort systems

∗ ACC• controller algorithms

• restraint systems• sensors

• safety systems∗ ABS∗ TCS∗ ESP

Tasks on the Vehicle:

Passenger Car as a Mechatronic System

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5.1 Modelling a vehicleOne application of Mechatronics „ Motor Vehicle“ : introduction of „intelligent“ control systems in modern motor vehicles

Goals:

• To increse the active and passive driving safety

• To increase the driving comfort

• To reduce the environmental pollution

• To reduce the fuel comsumption

Fuel injection system

Rear axle steering

Lambda-Control

ABS (AntiBlock-braking-Syst

TCS (Traction Control System)ESP (electronic stability program)Active wheel suspensions

Classification of the applicable methods based on the occuringFrequencies

< 30 Hz Handling

30 – 80 Hz comfort

> 50 Hz Acoustic

multi-body systems

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Torsionsstab

Geared shaft

Substitute Mechanism

Substitue system to model the elasticity of the rear transverse control armmounting Twist beam rear axle

Mechanical construction of a complete vehicle– VW GolfMcPherson suspension strut

Torsions beam

Mechanical Model:Complex spatial multi loop multi body system!

nB = 25 rigid bodies

k = 133 constraints

nL = 8 Multi body loops

f = 17 degrees of freedom

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Contact suurface body W2

Wheel carrierIntermediate body W1

Subsystem:Mc PhersonSuspension strut

Subsystem:Twist beam rear axle

Subsystem:Tyre-road contact

Subsystem:Joint elasticity

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Front wheel suspension

Vehicle Body/chassis

Rear wheelsuspension

Mixed structure:Tree structure

+8 multi body loops

- joint coordinates- generalised coordinates(Inputs)

- multi body loops

Topological Structure of the mechanical system of a complete vehicle

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5.1 Modelling a vehicleExample:McPherson-suspension(front left)

VW GolfnL = 3 Multi body loops

Joint coordinates;

Joint coordinates;

Joint coordinates; 4f

3f

1f

3

2

1

L

L

L

=

=

=

10:L

9:L

7:L

3

2

1

L3

L2

L1

=β

=β

=β

Subsystem3f

fS =

12s13s

11s11ϕ 1L

2L

3L

Suspension strut

Wheel carrier Geared shaft

Transversecontrol arm

rear elasticTransverse arm mounting

Constraints equations explicitelysolvable

⇒ 321 LLL →→

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1L 2L 3L

4L 5L 6L

1f =l

1f =l

3f =l

3f =l

4f =l

4f =l

11s

12s13s

22s

21s

complete front axle:

explicitlysolvable!

Block diagram of the kinematic Network:

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explicitlysolvable!

1f =l 1f =l8L7L

31s 32s3ψ

Block diagram of the rear axle (Twist beam rear axle):

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rear elasticTransverse arm mounting

Steering mechanism

Lenk-stockhebel

McPherson suspension strut

Five point spatial suspension system

Mechanical Model:complex spatial multi loop multi body system!

nB = 34 rigid bodies

k = 185 constraints


f = 19 degrees of freedom

Mechanical construction of a complete vehicle W 124 (Mercedes Benz)

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5.1 Modelling a vehicleSubsystems of a mechanical Model

Subsystem:McPherson suspension strut

Subsystem:5 point spatial suspension

Subsystem:Tyre road contact

Subsystem:Joint elasticity

W 124

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Front wheel suspension

Vehicle body/ chassisRear wheel suspension

Mixed Structure:Tree structure

+17 Multi body loops

- joint coordinates- generalised coordinates (Inputs)

- Multi body loops

Topological Structure of the mechanical system of a Complete vehicle W 124

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Example: five point spatial wheel suspension (left side)

W 124

Steering lever

Steering rod

Wheel carrier

wheelcarrier

12:L

11:L

11:L

11:L

11:L

12L12

L11

L10

L9

L8

11

10

9

8

=β

=β

=β

=β

=β

6f

5f

5f

5f

5f

12

11

10

9

8

L

L

L

L

L

=

=

=

=

=Joint coordinates;

Joint coordinates;

Joint coordinates;

Joint coordinates;

Joint coordinates;

2frS =

Subsystem



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1L 2L 3L

4L 5L 6L

1f =l

1f =l

3f =l

3f =l

4f =l

4f =l

11s

12s

22s

21s

explicitlysolvable!

1f =l

7L1κ

Block diagram:

W 124

complete front axis:

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Five point spatial suspension (left Side):

8L 9L 10L 11L 12L

3zc 3α

5 implicitequations;The remaining Explicitly solvable

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Subsystem D.O.F. Bodies Loops

ChassisFront wheel suspensionRear wheel suspension

Motor mountingDriving shaft

63226

11112112

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1003

vehicle 19 37 18

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Motor

Driving shaft

Five point spatial suspension

Chassis

Double wish bone

bodyjoint (1 DOF)Generalised coordinateisolated DOFTransmission of the drive DifferentialKinematic loops

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*

0 00 *

* *****

* *** *

** * *

* ** *

**

**

*

**

*

000

000

000

000

000

000

00

000

0000 0 0

000 0 0

00

000

symmetric }}

}

Degrees of freedomof the chassis

Degrees of freedom Of the front axis

Degrees of freedomOf the rear axis

Degrees of freedom Of the wheels

Chapter 5 Modelling und Simulation of vehicles 5.1 ... · McPherson suspension strut Five point...

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