PRELIMINARY STUDY FOR RIDE DYNAMICS MODEL OF SEMAR-T USING MATLAB-SIMULINK.

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PRELIMINARY STUDY FOR RIDE DYNAMICS MODEL OF SEMAR-T
USING MATLAB-SIMULINK

FINAL PROJECT
Submitted as a bachelor requirement in obtaining degree
in the mechanical engineering department,
faculty of engineering

by:
IPNU CANDRA
(I0408039)

MECHANICAL ENGINEERING DEPARTMENT
FACULTY OF ENGINEERING
UNIVERSITAS SEBELAS MARET
SURAKARTA
2013

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DEDICATIONS


To those who have been responsible, to them I dedicate this work anyway.
They are:
Allah SWT.
The creator and the master himself
Muhammad SAW.
The miracle and the inspiring
Taruni
A mother who always gave love and support
Mamad
A father who has always worked hard for the welfare of him children
Dedi Suwikyo, Tiyas Sismaya and Ina Susanti
Brother and sisters who has been assisting
Hadana Ulufannuri
A girl with a name and a story

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MOTTO

“Life is an adventure, so we should work hard to achieve our destinations”

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Preliminary Study For Ride Dynamics Model of Semar-T Using MATLABSimulink

Ipnu Candra
Mechanical Engineering Department
Faculty of Engineering
Universitas Sebelas Maret
Surakarta, Indonesia
E-mail: ipnu.candra@yahoo.com

Abstrack
The work is aimed to study the vertical, longitudinal and lateral response of
ride performance of Semar-T. The issues related to the design of vehicle model
with passive suspension system are discussed. A complete-vehicle seven-degreeof-freedom model is used to investigate the dynamics response by applying road
disturbances in sinusoidal road input excitation. Frequency response of the heave,
roll, pitch of the sprung mass and suspension deflection is obtained for the need of
studying the effect of given variation of both suspension stiffness coefficient and
suspension damping coefficient. Finally, the resulted responses in frequency
domain are then evaluated using ISO-2631 criteria to evaluate the passenger
comfortability.

Keywords: Semar-T, passive suspension system, comfortability, ISO-2631.

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Pembelajaran Awal Untuk Model Dinamika Ride Semar-T Menggunakan

Matlab-Simulink

Ipnu Candra
Jurusan Teknik Mesin
Fakultas Teknik
Universitas Sebelas Maret
Surakarta, Indonesia
E-mail: ipnu.candra@yahoo.com
Abstrak
Tujuan dari penelitian ini adalah untuk mempelajari respon vertikal,
longitudinal dan lateral dari performa ride Semar-T. Masalah-masalah yang terkait
dengan desain model kendaraan menggunakan sistem suspensi pasif akan dibahas
dalam penelitian ini. Model penuh kendaraan tujuh derajat kebebasan (DOF)
digunakan untuk meneliti respon dinamik dengan memberikan gangguan jalan
yang berbentuk sinusoid. Respon domain frekuensi heave, roll, pitch dari massa
sprung dan perpindahan suspensi diperoleh untuk mempelajari pengaruh dari
variasi nilai konstanta pegas dan peredam. Respon domain frekuensi kemudian
digunakan untuk evaluasi berdasarkan standar ISO-2631 guna mengevaluasi
kenyamanan penumpang.


Kata kunci: Semar-T, sistem suspensi pasif, kenyamanan, ISO-2631.

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PREFACE

First of all, the writer wants to thank to Allah SWT for the blessing and
guidance. Sholawat and also salam for my prophet Muhammad SAW, the person
who we will hope his syafaat in the end world later. The writer also would like to
say very much thank you to all family and friends for supporting writer to finish
this final project report well.
In this report, the writer is interested to discuss the Preliminary Study For
Ride Dynamics Model Of Semar-T Using Matlab-Simulink, including the
problem of influence road profile and variation of suspension stiffness coefficient
and suspension damping coefficient on the ride comfort of Semar-T. The writer
tried to make this final project report become the best final project report that ever

writer made.
The writer realized that this report is still far from being perfect. Therefore,
the writer will be happy to accept the suggestion and constructive criticism to
make this report be better. The writer hopes, this final project report would give
benefit for the others later.

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ACKNOWLEDGEMENT

Praise be to Allah SWT who always gives the power from first until end so
that Writer can finish this final project report well. However, the writer could not
accomplish this report without the help of many people. Therefore, the writer
would like to thank to all of them. They are:.
1. Ubaidillah S.T., M.Sc., as supervisor, who has patiently given his
guidance, advice, suggestions and time from the beginning up to the

complection of writing this report.
2. Wibowo S.T., M.T., as co-supervisor, who has given his guidance,
advice and encouragement in writing this report.
3. Didik Djoko Susilo S.T., M.T., the head of mechanical engineering
department for his permission to write this report.
4. Parents, you are everything in here, thanks for everything that you have
given for the writer.
5. Brother and sisters, for being the writer’s inspiration and giving strength
in facing this life.
6. Hadana Ulufannuri, who has given her support everyday.
7. All poeple and friends who can’t able to mention one by one.

Surakarta, July 2013

The writer

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TABLE OF CONTENTS

Page
COVER ........................................................................................................

i

ASSIGNMENT ............................................................................................

ii

APPROVAL .................................................................................................

iii

DEDICATIONS ............................................................................................

iv


MOTTO ........................................................................................................

v

ABSTRACK ................................................................................................

vi

PREFACE ....................................................................................................

viii

ACKNOWLEDGEMENT ............................................................................

ix

TABLE OF CONTENTS ..............................................................................

x


LIST OF TABLES .......................................................................................

xii

LIST OF FIGURES .....................................................................................

xiii

LIST OF EQUATIONS ................................................................................

xix

LIST OF NOTATIONS ...............................................................................

xx

CHAPTER I INTRODUCTION
1.1. Background ..............................................................................

1

1.2. Problem Statement ...................................................................

3

1.3. Scopes And Limitations ...........................................................

4

1.4. Objectives .................................................................................

4

1.5. Benefits ....................................................................................

4

1.6. Writing Systematics .................................................................

4

CHAPTER II LITERATURE REVIEW
2.1. Previous Researches ................................................................

6

2.2. Basic of Theory ........................................................................

8

2.2.1. Vehicle Ride Model .........................................................

8

2.2.2. Bumps and potholes profiles ............................................

11

CHAPTER III RESEARCH METHODOLOGY
3.1. Methodology ...........................................................................

13

3.2. Implementation of project .......................................................

15

3.3. Schedule .................................................................................
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CHAPTER IV RESULTS AND ANALYSIS
4.1. Simulation Setup .....................................................................

20

4.2. Arrangement of Variations .....................................................

21

4.3. Road sinusoidal Test ...............................................................

22

4.4. Validation ................................................................................

23

4.5. Results .....................................................................................

30

4.5.1. Simulation Results of 1st Variation (ks = constant) .........

30

nd

4.5.2. Simulation Results of 2 Variation (cs = constant) ........

44

4.6. International Standard ISO-2631 ............................................

57

4.7. Ride Comfort Comparison Using ISO-2631 ...........................

59

4.7.1. Under Full Load (m=1400 kg) Condition .......................

59

4.7.2. Under Full Load (m=1400 kg) Versus Half Load
(m=1200 kg) Conditions ..................................................

61

4.8. Analysis ...................................................................................

62

4.8.1. Frequency Responses ......................................................

62

4.8.1.1. Frequency Responses of 1st Variation .............

62

4.8.1.2. Frequency Responses of 2nd Variation ............

63

4.8.2. Time Responses................................................................

63

4.8.2.1. Time Responses of 1st Variation .....................

63

nd

4.8.2.2. Time Responses of 2 Variation .....................

64

4.8.3. ISO-2631 .........................................................................

64

4.8.3.1. ISO-2631 for 1st Variation (ks = constant) ......

64

4.8.3.2. ISO-2631 for 2nd Variation (cs = constant) .......

65

4.8.3.3. ISO-2631 for Full Load (m=1400 kg) Versus
Half Load (m=1200 kg) Conditions .....................

66

4.8.4. The Most Optimal Suspension System Variation ...........

66

CHAPTER V CONCLUSION AND RECOMMENDATION
5.1. Conclusion ...............................................................................

67

5.2. Recommendation......................................................................

67

REFERENCES .............................................................................................

68

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LIST OF TABLES

Page
Table 3.1.

Semar-T parameters ................................................................

15

Table 3.2.

Description of free body diagram symbol ..............................

16

Table 3.3.

Schedule of project .................................................................

19

Table 4.1.

Simulation Setup .....................................................................

20

Table 4.2.

List of parameter variations ....................................................

20

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LIST OF FIGURES

Page
Figure 2.1.

Vehicle body acceleration due to road excitation in
comparison with ISO ride comfort boundaries ....................

7

Figure 2.2.

Vehicle coordinate systems ..................................................

9

Figure 2.3.

Complete-vehicle model .......................................................

10

Figure 2.4.

(a) Rectangular cleat and (b) cosine-shaped bump ...............

11

Figure 3.1.

Flow chart of project ............................................................

14

Figure 3.2.

Complete Semar-T model .....................................................

16

Figure 3.2.a

Wheels Responses ................................................................

17

Figure 3.2.b

Body Responses ....................................................................

17

Figure 3.2.c

Scopes ...................................................................................

18

Figure 3.3.

Complete Semar-T block diagram ........................................

18

Figure 4.1.

Suspension damping coefficient testing result .....................

21

Figure 4.2.

Suspension stiffness coefficient testing result ......................

22

Figure 4.3.

Mode sinusoidal test .............................................................

23

Figure 4.4.

Validation graphic of body displacement response ..............

24

Figure 4.5.

Validation graphic of body acceleration response ................

24

Figure 4.6.

Validation graphic of pitch angle response ..........................

25

Figure 4.7.

Validation graphic of roll angle response .............................

25

Figure 4.8.

Validation graphic of front-left suspension travel response .

26

Figure 4.9.

Validation graphic of front-left wheel acceleration response

26

Figure 4.10.

Validation graphic of rear-left suspension travel response ..

27

Figure 4.11.

Validation graphic of rear-left wheel acceleration response

27

Figure 4.12.

Validation graphic of rear-right suspension travel response

28

Figure 4.13.

Validation graphic of rear-right wheel acceleration response

28

Figure 4.14.

Validation graphic of front-right suspension travel response

29

Figure 4.15.

Validation graphic of front-right wheel acceleration
response ................................................................................

Figure 4.16.

Bode plots of (a) body displacement and (b) body
acceleration response,
for different
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damping coefficients ( c s ) and constant value of the
suspension stiffness coefficients ( k s = 18000 N / m ) ...........
Figure 4.17.

31

Bode plots of (a) roll angle and (b) pitch angle response, for
different values of the suspension damping coefficients ( c s )
and constant value of the suspension stiffness coefficients
( k s = 18000 N / m ) ................................................................

Figure 4.18.

32

Bode plots of (a) front-left suspension travel and (b) frontleft wheel acceleration response, for different values of the
suspension damping coefficients ( c s ) and constant value of
the suspension stiffness coefficients ( k s = 18000 N / m ) .....

Figure 4.19.

33

Bode plots of (a) front-right suspension travel and (b) frontright wheel acceleration response, for different values of the
suspension damping coefficients ( c s ) and constant value of
the suspension stiffness coefficients ( k s = 18000 N / m ) .....

Figure 4.20.

34

Bode plots of (a) rear-left suspension travel and (b) rear-left
wheel acceleration response, for different values of the
suspension damping coefficients ( c s ) and constant value of
the suspension stiffness coefficients ( k s = 18000 N / m ) .....

Figure 4.21.

35

Bode plots of (a) rear-right suspension travel and (b) rearright wheel acceleration response, for different values of the
suspension damping coefficients ( c s ) and constant value of
the suspension stiffness coefficients ( k s = 18000 N / m ) .....

Figure 4.22.

36

Peak-to-Peak values of (a) body displacement and (b) body
acceleration response, for different values of the suspension
damping coefficients ( c s ) and constant value of the
suspension stiffness coefficients ( k s = 18000 N / m ) ...........

Figure 4.23.

Peak-to-Peak values of (a) roll angle and (b) pitch angle
response, for different values of the suspension damping
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coefficients ( c s ) and constant value of the suspension
stiffness coefficients ( k s = 18000 N / m ) .............................
Figure 4.24.

39

Peak-to-Peak values of (a) front-left suspension travel and
(b) front-left wheel acceleration response, for different
values of the suspension damping coefficients ( c s ) and
constant value of the suspension stiffness coefficients ( k s =
18000 N / m ) ........................................................................

Figure 4.25.

40

Peak-to-Peak values of (a) front-right suspension travel and
(b) front-right wheel acceleration response, for different
values of the suspension damping coefficients ( c s ) and
constant value of the suspension stiffness coefficients ( k s =
18000 N / m ) ........................................................................

Figure 4.26.

41

Peak-to-Peak values of (a) rear-left suspension travel and
(b) rear-left wheel acceleration response, for different
values of the suspension damping coefficients ( c s ) and
constant value of the suspension stiffness coefficients ( k s =
18000 N / m ) ........................................................................

Figure 4.27.

42

Peak-to-Peak values of (a) rear-right suspension travel and
(b) rear-right wheel acceleration response, for different
values of the suspension damping coefficients ( c s ) and
constant value of the suspension stiffness coefficients ( k s =
18000 N / m ) ........................................................................

Figure 4.28.

43

Bode plots of (a) body displacement and (b) body
acceleration response, for different values of the suspension
stiffness coefficients ( k s ) and constant value of the
suspension damping coefficients ( c s = 900 Ns / m ) .............

Figure 4.29.

Bode plots of (a) roll angle and (b) pitch angle response, for
different values of the suspension stiffness coefficients ( k s )
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...and constant value
of thetosuspension
damping coefficients

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( c s = 900 Ns / m ) ...................................................................
Figure 4.30.

46

Bode plots of (a) front-left suspension travel and (b) frontleft wheel acceleration response, for different values of the
suspension stiffness coefficients ( k s ) and constant value of
the suspension damping coefficients ( c s = 900 Ns / m ) .......

Figure 4.31.

47

Bode plots of (a) front-right suspension travel and (b) frontright wheel acceleration response, for different values of the
suspension stiffness coefficients ( k s ) and constant value of
the suspension damping coefficients ( c s = 900 Ns / m ) .......

Figure 4.32.

48

Bode plots of (a) rear-left suspension travel and (b) rear-left
wheel acceleration response, for different values of the
suspension stiffness coefficients ( k s ) and constant value of
the suspension damping coefficients ( c s = 900 Ns / m ) .......

Figure 4.33.

49

Bode plots of (a) rear-right suspension travel and (b) rearright wheel acceleration response, for different values of the
suspension stiffness coefficients ( k s ) and constant value of
the suspension damping coefficients ( c s = 900 Ns / m ) .......

Figure 4.34.

50

Peak-to-Peak values of (a) body displacement and (b) body
acceleration response, for different values of the suspension
stiffness coefficients ( k s ) and constant value of the
suspension damping coefficients ( c s = 900 Ns / m ) .............

Figure 4.35.

51

Peak-to-Peak values of (a) roll angle and (b) pitch angle
response, for different values of the suspension stiffness
coefficients ( k s ) and constant value of the suspension
damping coefficients ( c s = 900 Ns / m ) ...............................

Figure 4.36.

Peak-to-Peak values of (a) front-left suspension travel and
(b) front-left wheel acceleration response, for different
values of the suspension stiffness coefficients ( k s ) and
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constant value of the suspension damping coefficients ( c s =
900 Ns / m ) ...........................................................................
Figure 4.37.

53

Peak-to-Peak values of (a) front-right suspension travel and
(b) front-right wheel acceleration response, for different
values of the suspension stiffness coefficients ( k s ) and
constant value of the suspension damping coefficients ( c s =
900 Ns / m ) ...........................................................................

Figure 4.38.

54

Peak-to-Peak values of (a) rear-left suspension travel and
(b) rear-left wheel acceleration response, for different
values of the suspension stiffness coefficients ( k s ) and
constant value of the suspension damping coefficients ( c s =
900 Ns / m ) ...........................................................................

Figure 4.39.

55

Peak-to-Peak values of (a) rear-right suspension travel and
(b) rear-right wheel acceleration response, for different
values of the suspension stiffness coefficients ( k s ) and
constant value of the suspension damping coefficients ( c s =
900 Ns / m ) ...........................................................................

Figure 4.40.

ISO

2631

“fatigue-decreased

56

proficiency boundary”:

vertical vibration limits as a function of frequency and
exposure time [2] ..................................................................
Figure 4.41.

58

Vehicle body acceleration due to road excitation in
comparison with ISO ride comfort boundaries, for different
values of the suspension damping coefficients ( c s ) and
constant value of the suspension stiffness coefficients ( k s =
18000 N / m ) ........................................................................

Figure 4.42.

59

Vehicle body acceleration due to road excitation in
comparison with ISO ride comfort boundaries, for different
values of the suspension stiffness coefficients ( k s ) and
constant value of the suspension damping coefficients ( c s =
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900 Ns / m ) ...........................................................................

60

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Figure 4.43.

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Vehicle body acceleration due to road excitation in
comparison with ISO ride comfort boundaries, under full
load (m=1400 kg) versus half load (m=1200 kg) conditions

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LIST OF EQUATIONS

Page
Equation 2.1.

RMS value of the sprung mass displacement ...................

7

Equation 2.2.

The second law of Newton ................................................

10

Equation 2.3.

Body vertical response ......................................................

10

Equation 2.4.

Body pitch response ..........................................................

10

Equation 2.5.

Body roll response ............................................................

11

Equation 2.6.

Front-left wheel response ..................................................

11

Equation 2.7.

Rear-left wheel response ...................................................

11

Equation 2.8.

Rear-right wheel response .................................................

11

Equation 2.9.

Front-right wheel response ................................................

11

Equation 2.10. Height of rectangular cleat ................................................

12

Equation 2.11. Height of cosine-shaped bump ..........................................

12

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LIST OF NOTATIONS

ms

= Sprung mass ............................................................................

(kg)

I yy

= Pitch moment of inertia ...........................................................

(kgm2)

I xx

= Roll moment of inertia ............................................................

(kgm2)

mu1

= Front-left unsprung mass .........................................................

(kg)

mu2

= Rear-left unsprung mass ..........................................................

(kg)

mu3

= Rear-right unsprung mass ........................................................

(kg)

mu4

= Front-right unsprung mass ......................................................

(kg)

ks1

= Front-left suspension stiffness coefficient ..............................

(N/m)

ks2

= Rear-left suspension stiffness coefficient ................................

(N/m)

ks3

= Rear-right suspension stiffness coefficient .............................

(N/m)

ks4

= Front-right suspension stiffness coefficient ............................

(N/m)

cs1

= Front-left suspension damping coefficient ..............................

(N/m)

cs 2

= Rear-left suspension damping coefficient ...............................

(N/m)

cs 3

= Rear-right suspension damping coefficient .............................

(N/m)

cs 4

= Front-right suspension damping coefficient ............................

(N/m)

lf

= Side distance from center of gravity to the front axle .............

(m)

lr

= Side distance from center of gravity to the rear axle ...............

(m)

a fl

= Frontal distance from center of gravity to the front-left axle ..

(m)

a rl

= Frontal distance from center of gravity to the rear-left axle ...

(m)

a rr

= Frontal distance from center of gravity to the rear-right axle .

(m)

a fr

= Frontal distance from center of gravity to the front-right axle

(m)

x1

= Sprung mass heavy displacement ............................................

(m)

x2

= Sprung mass pitch angular displacement ................................

(rad)

x3

= Sprung mass roll angular displacement ...................................

(rad)

x4

= Front-left unsprung mass displacement ...................................
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(m)

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x5

= Rear-left unsprung mass displacement ....................................

(m)

x6

= Rear-right unsprung mass displacement .................................

(m)

x7

= Front-right unsprung mass displacement ................................

(m)

xin1

= Front-left displacement input ..................................................

(m)

xin 2

= Rear-left displacement input ...................................................

(m)

xin 3

= Rear-right displacement input .................................................

(m)

xin 4

= Front-right displacement input ................................................

(m)

z1.RMS

= RMS value of the sprung mass =

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