Simulation Study On Active Seat Suspension For A Passenger Car

I/We* have read this thesis and from my/our* opinion this thesis

is sufficient in aspects of scope and quality for awarding Bachelor of Mechanical Engineering (Automotive)

Signature : ……….

Name of Supervisor : Mohd Hanif bin Harun

Date : 13 May 2010

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SIMULATION STUDY ON ACTIVE SEAT SUSPENSION FOR A PASSENGER CAR

MUHAMAD SUFFIAN EFFENDI BIN MD YUSUF

This report is presented as

a requirement for a degree undergraduate in Bachelor of Mechanical Engineering (Automotive)

Faculty of Mechanical Engineering Universiti Teknikal Malaysia Melaka

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“I declare this report is on my own work except for summary and quotes that I have mentioned its sources”

Signature :………..

Name of Author : Muhamad Suffian Effendi Md Yusuf

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ACKNOWLEDGEMENTS

Praise is to Allah S.W.T to Whom seek help and guidance and under His benevolence we exist and without his help this project could not have been accomplish.

I would like to take this opportunity to express my gratitude to my supervisor En. Mohd Hanif bin Harun his constant guidance and encouragement during the past fourteen weeks. He always appreciates whatever little progress I have achieved, and continuously gives me much inspiration by sharing his precious knowledge and experience. I shall always remember the fun we have had together.

Finally, but most importantly of all, my parents Tifah bte Masran and should receive my greatest appreciation for their enormous love. They always respect what I want to do and give me their full support. The support from my siblings is also highly appreciated.

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ABSTRACT

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ABSTRAK

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TABLE OF CONTENT

CHAPTER TITLE PAGE

PREFACE ii

DEDICATION iii

ACKNOWLEDGEMENT iv

ABSTRACT v

ABSTRAK vi

TABLE OF CONTENT vii

LIST OF TABLE ix

LIST OF FIGURE x

LIST OF SYMBOL xii

NOMENCLATURE xvii

1 INTRODUCTION

1.1 Background 1

1.2 Objective 2

1.3 Scope 2

1.4 Problem statement 3

1.5 Thesis Outline 4

1.5.1 Chapter summary 6

2 LITERATURE REVIEW

2.1 Introduction 7

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2.3 Passive suspension 9

2.4 Semi-active suspension 11

2.4.1 Electroreheological 12

2.5 Active suspension 14

2.5.1 Electric Servo-Motor Actuator 15

2.6 Active Vs. Passive suspension 16

3 METHODOLOGY

3.1 Introduction 20

3.2 Seat Suspension Model 22

3.2.1 Model Seat Ride Model Parameter 23 3.3 Full Model of Suspension Ride Model 24

3.4 Free body diagram 26

3.5 Mathematical Model 27

3.6 Controller 32

3.6.1 Actuator Control (Decoupling Transformation) 34

3.7 MATLAB Simulink Model 36

4 RESULTS AND DISCUSSION

4.1 MATLAB Simulink Result and Discussion 44

4.2 Result validation 52

5 CONCLUSION AND RECOMMENDATION

5.1 Conclusion 57

5.2 Recommendation 58

REFERENCE 59

BIBLIOGRAPHY 60

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LIST OF TABLE

TABLE TITLE PAGE

1.5.1 Gantt chart Of Project Outline for PSM 1 4 1.5.2 Gantt chart Of Project Outline for PSM 2 5 2.6 Comparison between Active and Passive Suspension 17

3.1 Gantt chart of Project Research 21

3.2.1 Parameter for Ride Model 23

4.1.1 Reduction of magnitude for acceleration 47

4.1.2 Reduction of Magnitude for Speed 50

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LIST OF FIGURE

FIGURE TITLE PAGE

2.1 Motion of seat with safety 8

2.3.1 Seat model of passive suspension system 10

2.3.2 FBD Seat model of passive suspension system 10 2.3.3 Result of transmissibility of different foam 11

2.4.1 ER Seat Suspension System 12

2.4.2 Experimental Apparatus for ER Seat Suspension System 13 2.4.3 Frequency Response ER seat suspension System 13 2.5.1 Active suspension seat develop by Georgia Institute of

technology 15

2.5.2 Analysis model of servo-motor seat suspension 16 2.5.3 Control system of servo-motor seat suspension 16

2.6 Time response between used and unused controller in

suspension system 18

3.1 Project Flow Chart 20

3.2 Seat Model 22

3.3.1 Seat ride model for passive system 25

3.3.2 Seat Model for Active System with Vehicle Suspension 25 3.4.1 FBD for seat ride model for passive system 26

3.4.2 Rolling Moment 30

3.4.3 Pitching Moment 31

3.5 Active Vibration Control 33

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3.7.2 Function Block Parameter for PID Controller 37

3.7.3 Decoupling Transformation Subsystem 37

3.7.4 Subsystem for Active Seat Suspension 38

3.7.5 Subsystem For Passive Seat Suspension 39

3.7.6 Subsystem for Seat Pitchd & Rolld 39

3.7.7 Subsystem for Seat Pitch & Roll 40

3.7.8 Subsystem for Seat Damper 40

3.7.9 Subsystem for Seat Spring 41

3.7.10 Sample Subsystem for Seat Mounting 41

3.7.11 Subsystem for Seat Vertical Motion 42

3.7.12 Subsystem for Seat Pitching Moment 42

3.7.13 Subsystem for Seat Rolling Moment 43

4.1.1 Disturbance Input (Road Bump) 45

4.1.2 Seat Vertical Acceleration vs. Time 45

4.1.3 Seat Pitch Acceleration vs. Time 46

4.1.4 Seat Roll Acceleration vs. Time 46

4.1.5 Seat Vertical Speeds vs. Time 48

4.1.6 Seat Pitch Rate vs. Time 48

4.1.7 Seat Roll Rate vs. Time 49

4.1.8 Seat Vertical Displacement vs. Time 50

4.1.9 Seat Pitch Angle vs. Time 51

4.1.10 Seat Roll Angle vs. Time 51

4.2.1 Graph of Displacement and Acceleration vs. Time for Passive

and Active Suspension from Theory 53

4.2.2 Graph of Displacement and Acceleration vs. Time for Passive

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LIST OF SYMBOLS

SYMBOL TITLE UNIT

Seat Rolling Angle rad

̇ Seat Roll Rate At Body Centre Of Gravity rads-1 ̈ Seat Roll Acceleration At Body Centre Of Gravity rads-2

Vehicle Rolling Angle rad

̇ Vehicle Roll Rate At Body Centre Of Gravity rads-1 ̈ Vehicle Roll Acceleration At Body Centre Of Gravity rads-2

Seat Pitching Angle rad

̇ Seat Pitch Rate At Body Centre Of Gravity rads-1 ̈ Seat Pitch Acceleration At Body Centre Of Gravity rads-2

Vehicle Pitching Angle rad

̇ Vehicle Pitch Rate At Body Centre Of Gravity rads-1 ̈ Vehicle Pitch Acceleration At Body Centre Of Gravity rads-2

Cfl Vehicle Front Left Damper Coefficient Nsm-1

Cfr Vehicle Front Right Damper Coefficient Nsm-1

Crl Vehicle Rear Left Damper Coefficient Nsm-1

Crr Vehicle Rear Right Damper Coefficient Nsm-1

Csfl Seat Front Left Damper Coefficient Nsm-1

Csfr Seat Front Right Damper Coefficient Nsm-1

Csrl Seat Rear Left Damper Coefficient Nsm-1

Csrr Seat Rear Right Damper Coefficient Nsm-1

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Disturbance Force At Rear-Left Unsprung Mass N Disturbance Force At Rear-Right Unsprung Mass N

F Force N

Fdsfl Seat Front-Left Damper Force N

Fdsfr Seat Front-Right Damper Force N

Fdsrl Seat Rear-Left Damper Force N

Fdsrr Seat Rear-Right Damper Force N

Fdcfl Vehicle Front-Left Damper Force N

Fdcfr Vehicle Front-Right Damper Force N

Fdcrl Vehicle Rear-Left Damper Force N

Fdcrr Vehicle Rear-Right Damper Force N

Fssfl Seat Front-Left Spring Force N

Fssfr Seat Front-Right Spring Force N

Fssrl Seat Rear-Left Spring Force N

Fssrr Seat Rear-Right Spring Force N

Fscfl Vehicle Front-Left Spring Force N

Fscfr Vehicle Front-Right Spring Force N

Fscrl Vehicle Rear-Left Spring Force N

Fscrr Vehicle Rear-Right Spring Force N

Fv Vertical Force N

Ips Seat Sprung Mass Pitch Inertia kgm-2

Irs Seat Sprung Mass Roll Inertia kgm-2

Ipc Vehicle Sprung Mass Pitch Inertia kgm-2

Irc Vehicle Sprung Mass Roll Inertia kgm-2

Kfl Vehicle Front-Left Spring Coefficient Nm-1

Kfr Vehicle Front-Right Spring Coefficient Nm-1

Krl Vehicle Rear-Left Spring Coefficient Nm-1

Krr Vehicle Rear-Right Spring Coefficient Nm-1

Ksfl Seat Front-Left Spring Coefficient Nm-1

Ksfr Seat Front-Right Spring Coefficient Nm-1

Ksrl Seat Rear-Left Spring Coefficient Nm-1

Ksrr Seat Rear-Right Spring Coefficient Nm-1

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Ktfr Tire Front-Right Spring Coefficient Nm-1

Ktrl Tire Rear-Left Spring Coefficient Nm-1

Ktrr Tire Rear-Right Spring Coefficient Nm-1

Kp Proportional Gains Respectively Ki Integral Gains Respectively Kd Derivative Gains Respectively

ms Seat Mass kg

mc Vehicle Mass kg

mw Wheel Mass kg

Mp Pitch Moment Nm

Mr Roll Moment Nm

Ts Seat Width m

Tc Vehicle Track Width m

Wsd Seat Body Length From CG to Front Mounting m

Wsb Seat Body Length From CG to Rear Mounting m

Wcd Seat Body Length From CG to Front Tire m

Wcb Seat Body Length From CG to Rear Tire m

Zc Sprung Mass Displacement At Vehicle Body CG m ̇ Sprung Mass Velocity At Vehicle Body CG ms-1 ̈ Sprung Mass Acceleration At Vehicle Body CG ms-1

Zcfl Front-Left Vehicle Displacement m

Zcfr Front-Right Vehicle Displacement m

Zcrl Rear-Left Vehicle Displacement m

Zcrr Rear-Right Vehicle Displacement m

̇ Vehicle Velocity At Front-Left Corner ms-1 ̇ Vehicle Velocity At Front-Right Corner ms-1 ̇ Vehicle Velocity At Rear-Left Corner ms-1 ̇ Vehicle Velocity At Rear-Right Corner ms-1 ̈ Vehicle Acceleration At Front-Left Corner ms-2 ̈ Vehicle Acceleration At Front-Right Corner ms-2 ̈ Vehicle Acceleration At Rear-Left Corner ms-2 ̈ Vehicle Acceleration At Rear-Right Corner ms-2

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̇ Sprung Mass Velocity At Seat Body CG ms-1

̈ Sprung Mass Acceleration At Seat Body CG ms-1

Zsfl Front-Left Seat Displacement m

Zsfr Front-Right Seat Displacement m

Zsrl Rear-Left Seat Displacement m

Zsrr Rear-Right Seat Displacement m

̇ Seat Velocity At Front-Left Corner ms-1

̇ Seat Velocity At Front-Right Corner ms-1

̇ Seat Velocity At Rear-Left Corner ms-1

̇ Seat Velocity At Rear-Right Corner ms-1

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NOMENCLATURE

DOF Degree of Freedom FBD Free Body Diagram

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CHAPTER 1

INTRODUCTION

1.1 Background

Suspension is a system encircles spring and shock absorber to absorb any vibration from road roughness and on-board source. It is for giving comfortable to the driver and passenger.

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subject of the research and development in last decades. The reason is commercial as well as being scientific. The main aim of the commercial activity is the desire of the automotive manufacturers to improve the performance and quality of their products. On the other hand, researchers and control system designers have claimed that the active control of the vehicle suspension system is possible when the developments in actuators, sensors and electronics have been considered. In the last twenty years, many studies have been published on active and semi-active suspension systems.

1.2 Objective

The objectives of this project are to propose control mechanism of the active seat suspension for a ground vehicle in order to improve riding comfort of the vehicle.

1.3 Scope

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1.4 Problem Statement

Normally in a vehicle have a vibration. Source of vehicle vibration is generally is divided into two classes:

 Road roughness  On-board source

G.M Alan etc. (2005) said effect from the vibration can transfer from vehicle seat to human body. Its affect not only comfort, working efficiency and performance but can affect at health and safety when driving. Injury statistics from the Mine Safety and Health Administration (MSHA) showed incidences of exposure to whole-body vibration (WBV) and it also support by S.J Kooster (2004).

Operators of mine vehicles are in particular subject to high levels of vibrations under very constraining conditions. The vehicle operator often is more confined to a less space than in normal cars or vehicles and the seats are not equipped with a suspension system.

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1.5 Thesis Outline

Table 1.5.1: Gantt chart of Project Outline for PSM 1

NO ITEM WEEK(S)

JULY '09 AUG '09 SEPT '09 OCT '09

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 1 Project Title

Discussion 1

2 Introduction 2

3 Literature Review 3

4 Research

Methodology 4

5 Report Writing 3

6 Report Submission 1

Target

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Table 1.5.2: Gantt chart of Project Outline for PSM 2

NO ITEM WEEK(S)

JAN '10 FEB '10 MAR '10 APR '09

01 02 03 04 05 06 07 08 09 10 11 12 13 14 15 16

1 PSM 2 Discussion 1

2 Build Simulation (using

MATLAB) 4

3 Simulation (MATLAB) 3

4 Result Discussion 2

5 Report Writing 4

6 Report Submission 1

Target

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1.5.1 Chapter Summary

Chapter 1: This chapter explains about the objective and scope of this

project. In this chapter also have the problem about the conventional and newer system.

Chapter 2: This chapter describes about the previous study about the seat suspension system.

Chapter 3: This chapter shows the system in mathematical modeling 10DOF full ride model.