design and simulation automobile active suspension system

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DESIGN AND SIMULATION AUTOMOBILE ACTIVE SUSPENSION SYSTEM

MOHD ASQALANI BIN NAHARUDIN

UNIVERSITI MALAYSIA PAHANG

UNIVERSITI MALAYSIA PAHANG BORANG PENGESAHAN STATUS TESIS

JUDUL: DESIGN AND SIMULATION AUTOMOBILE ACTIVE SUSPENSION SYSTEM

SESI PENGAJIAN: 2007/2008 Saya MOHD ASQALANI BIN NAHARUDIN (HURUF BESAR)

mengaku membenarkan tesis (PSM/Sarjana/Doktor Falsafah)* ini disimpan di Knowledge Management Centre dengan syarat-syarat kegunaan seperti berikut: 1. 2. 3. 4. Tesis adalah hakmilik Universiti Malaysia Pahang. Knowledge Management Centre dibenarkan membuat salinan untuk tujuan pengajian sahaja. Perpustakaan dibenarkan membuat salinan tesis ini sebagai bahan pertukaran antara institusi pengajian tinggi. **Sila tandakan ( )

SULIT

(Mengandungi maklumat yang berdarjah keselamatan atau kepentingan Malaysia seperti yang termaktub di dalam AKTA RAHSIA RASMI 1972) (Mengandungi maklumat TERHAD yang telah ditentukan oleh Organisasi/badan dimana penyelidikan dijalankan)

TERHAD

TIDAK TERHAD

Disahkan oleh ___________________________________ (TANDATANGAN PENULIS) Alamat Tetap: NO 466 BLOK 21 (F) KERATONG 3 26900 BDR TUN RAZAK PAHANG. Tarikh: ____________________________ ___________________________________ (TANDATANGAN PENYELIA) Nama Penyelia: MR. MOHD SHAHRIR MOHD SANI

Tarikh: ____________________________

CATATAN: * Potong yang tidak berkenaan ** Jika tesis ini SULIT atau TERHAD, sila lampirkan surat daripada pihak berkuasa/organisasi berkenaan dengan menyatakan sekali sebab dan tempoh tesis ini perlu dikelaskan sebagai SULIT atau TERHAD Tesis dimaksudkan sebagai tesis bagi Ijazah Doktor Falsafah dan Sarjana secara penyelidikan, atau disertasi bagi pengajian secara kerja kursus dan penyelidikan, atau Laporan Projek Sarjana Muda (PSM)

DESIGN AND SIMULATION AUTOMOBILE ACTIVE SUSPENSION SYSTEM

MOHD ASQALANI BIN NAHARUDIN

A report submitted in partial fulfilment of the requirements for the award of the degree of Bachelor of Mechanical Engineering with Automotive Engineering

Faculty of Mechanical Engineering UNIVERSITI MALAYSIA PAHANG

NOVEMBER 2008

SUPERVISORS DECLARATION

We hereby declare that we have checked this project and in our opinion this project is satisfactory in terms of scope and quality for the award of the degree of Bachelor of Mechanical Engineering with Automotive

Signature

Name of Supervisor: Position: Date:

Signature Name of Panel: Position: Date:

STUDENTS DECLARATION

I hereby declare that the work in this thesis is my own except for quotations and summaries which have been duly acknowledged. The thesis has not been accepted for any degree and is not concurrently submitted for award of other degree.

Name: Mohd Asqalani Bin Naharudin ID Number: MH05058 Date:

ACKNOWLEDGEMENTS In the name of ALLAH SWT, the most Gracious, who has given me the strength and ability to complete this study. All perfect praises belong to ALLAH SWT, lord of the universe. May His blessing upon the prophet Muhammad SAW and member of his family and companions.

I gratefully acknowledge the co-operation of En. Mohd Shahrir Mohd Sani and Dr. Wan Azhar bin Wan Yusoff who has provided me with the reference, guidance, encouragement and support in completing this thesis. All the regular discussion sessions that we had throughout the period of study have contributed to the completion of this project.

Thank you to my classmate for providing an enjoyable study environment. Finally, I would like to thank my family for their encouragement, support and patience.

ABSTRACT

The purpose of this project is to design and simulate a semi-active suspension system for a quarter car model by controlling two input, spring stiffness, k s, and damper rate, bs. The performance of this system will be compared with the passive suspension system. There are two parameters to be observed in this study namely, the sprung mass acceleration and the suspension distortion. The performance of this system will be determined by performing computer simulations using the MATLAB and SIMULINK toolbox. For the first experiment, the damper rate was set to constant while spring stiffness was set from 10507 N/m to 131345 N/m. at lower spring stiffness leads improvement in ride quality but increased the suspension distortion at lower time. At second experiment, the spring stiffness was set to constant while the damper rate was from 1000 N.sec/m to 1400 N.sec/m. Increases in damper rate improve the ride quality but slower roll-off will occurred. In the third experiment, the damper rate value was set to maximum while spring stiffness was set to minimum to achieve optimal performance. The simulation results show that the semi-active system could provide significant improvements in the ride quality and road handling compare with the passive system.

ABSTRAK Tujuan projek ini adalah mereka bentuk dan simulasi satu separa aktif sistem suspensi untuk satu perempat model kereta dengan kawalan dua input, melompat kekakuan, ks, dan kadar penyerap, bs. Prestasi sistem ini akan dibanding dengan sistem suspensi pasif. Terdapat dua parameter untuk diperhatikan dalam kajian ini yakni, pecutan besarbesaran dan melompat dan herotan suspensi. Prestasi sistem ini akan ditentukan dengan menggunakan simulasi komputer menggunakan peti alat MATLAB dan SIMULINK. Untuk eksperiment pertama, kadar penyerap dijadikan pemalar manakala nilai kadar keanjalan spring dari 10507 N/m ke 131345 N/m. Pada nilai keanjalan spring rendah memberikan peningkatan dalam kualiti pemanduan tetapi herotan suspense meninggi pada kemudian masa. Bagi eksperimen kedua, keanjalan spring dijadikan pemalar manakala nilai kadar penyerap dari 1000 N.sec/m ke 1400 N.sec/m. Kenaikan pada kadar penyerapmeningkatkan kualiti pemanduan tetapi slower roll-off akan terjadi. Dalam eksperimen ketiga, kadar penyerap menggunakan nilai maksimum manakala keanjalan spring menggunakan nilai minimum untuk mendapat prestasi optimum. Hasil simulasi menunjukkan bahawa separa aktif sistem boleh memberikan peningkatan penting dalam kualiti pemanduan dan pengendalian kenderaan berbanding sistem pasif.

TABLE OF CONTENTS

Page SUPERVISORS DECLARATION STUDENTS DECLARATION ACKNOWLEDGEMENTS ABSTRACT ABSTRAK TABLE OF CONTENTS LIST OF TABLES LIST OF FIGURES LIST OF SYMBOLS LIST OF ABBREVIATIONS xiii xiv ii iii iv v vi vii x xi

CHAPTER 1

INTRODUCTION

1.1 1.3 1.3 1.4

Project Background Problem Statement Objectives of Study Scopes of Work

1 2 2 3

CHAPTER 2

LITERATURE REVIEW

2.1 2.2 2.3 2.4

Introduction Semi-active Suspension System Quarter Car Model Control System

4 4 6 8

2.5 2.6 2.7

Fuzzy Logic Controller Matlab/Simulink Paper Review 2.7.1 An Observer Design for Active Suspension System 2.7.2 Simulation of a Suspension System with Adaptive Fuzzy Active Force Control 2.7.3 Using Fuzzy Logic to Control Active Suspension System of One-half-car Model 2.7.4 Design and Simulation of Automatic Suspension Control System of the Four-Wheel Vehicle 2.7.5 Using Car Semi-Active Suspension Systems to Decrease Undesirable Effects of Road Excitations on Human Health 2.7.6 Design of a Nonlinear Optimal Controller for Active Suspension in Order to Vertical Motion Control of Automotive

9 10 11 11 11

12

13

13

15

CHAPTER 3

DURABILITY ASSESSMENT METHODS

3.1 3.2 3.3 3.4

Introduction Methodology of Flow Chart Model Design Simulation

17 18 19 20

CHAPTER 4

RESULTS AND DISCUSSION

4.1 4.2

Introduction Data Analysis 4.2.1 Analysis of Vibration 4.2.2 Result Of Constant Damper Rate And Variable Spring Stiffness

24 24 24 26

4.2.3 Result Of Constant Spring Stiffness And Variable Damper Rate 4.2.4 Results For Optimal Performance

33

40

CHAPTER 5

CONCLUSION AND RECOMMENDATIONS

5.1 5.2 5.3

Introduction Conclusions Recommendations for the Future Research

42 42 43

REFERENCES APPENDICES A Gantt Chart

LIST OF TABLES

Table No. 3.1 4.1 4.2 Suspension Model parameters Various Spring Stiffness Values Various Damper Rate Value

Page 19 25 32

LIST OF FIGURES

Figure No. 2.1 2.2 2.3 2.4 2.5 3.1 3.2 3.3 3.4 3.5 4.1 4.2 4.3 4.4 4.5 4.6 4.7 4.8 Schematic of a variable damper Commercial linear MR fluid-based damper Schematic of semi-active suspension system Quarter-car active suspension system One half car model Flow Chart Two DOF suspension model Block diagram of overall suspension system Block diagram for semi-active suspension system Block diagram for passive suspension system Sprung mass acceleration Suspension Distortion Sprung mass acceleration for ks=10507 N/m Suspension distortion for ks=10507 N/m Sprung mass acceleration for ks=21890 N/m Suspension distortion for ks=21890 N/m Sprung mass acceleration for ks=35025 N/m Suspension distortion for ks=35025 N/m

Page 5 5 6 7 12 18 19 21 22 23 25 25 27 27 28 28 29 29

4.9 4.10 4.11 4.12 4.13 4.14 4.15 4.16 4.17 4.18 4.19 4.20 4.21 4.22 4.23 4.24 4.25 4.26

Sprung mass acceleration for ks=56916 N/m Suspension distortion for ks=56916 N/m Sprung mass acceleration for ks=78807 N/m Suspension distortion for ks=78807 N/m Sprung mass acceleration for ks=131345 N/m Suspension distortion for ks=131345 N/m Sprung mass acceleration for bs =1000 N.sec/m Suspension distortion for bs =1000 N.sec/m Sprung mass acceleration for bs =1100 N.sec/m Suspension distortion for bs =1100 N.sec/m Sprung mass acceleration for bs =1200 N.sec/m Suspension distortion for bs =1200 N.sec/m Sprung mass acceleration for bs =1300 N.sec/m Suspension distortion for bs =1300 N.sec/m Sprung mass acce