# 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

commit to user 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: commit to user

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

Ipnu Candra

Mechanical Engineering Department Faculty of Engineering

Universitas Sebelas Maret Surakarta, Indonesia

E-mail:

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-degree- of-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

Ipnu Candra

Jurusan Teknik Mesin Fakultas Teknik

Universitas Sebelas Maret Surakarta, Indonesia

E-mail:

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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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.

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

st

4.5.1. Simulation Results of 1 Variation (k s = constant) .........

30

nd

4.5.2. Simulation Results of 2 Variation (c s = 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

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

62

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

63 4.8.2. Time Responses................................................................

63

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

63

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

64 4.8.3. ISO-2631 .........................................................................

64

st

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

64

s

nd

4.8.3.2. ISO-2631 for 2 Variation (c s = 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

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 ................................................................................

29 Figure 4.16. Bode plots of (a) body displacement and (b) body

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acceleration response, for different values of the suspension

c ) and constant value of the

damping coefficients ( s suspension stiffness coefficients ( k = 18000 N / m ) ........... s

31 Figure 4.17. Bode plots of (a) roll angle and (b) pitch angle response, for

c )

different values of the suspension damping coefficients ( s and constant value of the suspension stiffness coefficients

k = 18000 ( N / m ) ................................................................ s

32 Figure 4.18. Bode plots of (a) front-left suspension travel and (b) front- left wheel acceleration response, for different values of the suspension damping coefficients ( c ) and constant value of s

k = 18000 / the suspension stiffness coefficients ( N m ) ..... s

33 Figure 4.19. Bode plots of (a) front-right suspension travel and (b) front- right wheel acceleration response, for different values of the

c ) and constant value of

suspension damping coefficients ( s the suspension stiffness coefficients ( k = 18000 N / m ) ..... s

34 Figure 4.20. Bode plots of (a) rear-left suspension travel and (b) rear-left wheel acceleration response, for different values of the suspension damping coefficients ( c ) and constant value of s the suspension stiffness coefficients ( k = 18000 N / m ) ..... s

35 Figure 4.21. Bode plots of (a) rear-right suspension travel and (b) rear- right wheel acceleration response, for different values of the suspension damping coefficients ( c ) and constant value of s

k = 18000 the suspension stiffness coefficients ( N / m ) ..... s

36 Figure 4.22. Peak-to-Peak values of (a) body displacement and (b) body acceleration response, for different values of the suspension

c ) and constant value of the

damping coefficients ( s

k = 18000 N / m suspension stiffness coefficients ( ) ........... s

38 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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c ) and constant value of the suspension

coefficients ( s stiffness coefficients ( k = 18000 N / m ) ............................. s

39 Figure 4.24. 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 ) and s

k =

constant value of the suspension stiffness coefficients ( s 18000 N / m ) ........................................................................

40 Figure 4.25. 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 ) and s

k =

constant value of the suspension stiffness coefficients ( s 18000 N / m ) ........................................................................

41 Figure 4.26. 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 ) and s

k =

constant value of the suspension stiffness coefficients ( s 18000 N / m ) ........................................................................

42 Figure 4.27. Peak-to-Peak values of (a) rear-right suspension travel and (b) rear-right wheel acceleration response, for different

c ) and

values of the suspension damping coefficients ( s

k =

constant value of the suspension stiffness coefficients ( s / 18000 N m ) ........................................................................

43 Figure 4.28. Bode plots of (a) body displacement and (b) body acceleration response, for different values of the suspension

k ) and constant value of the

stiffness coefficients ( s suspension damping coefficients ( c = 900 Ns / m ) ............. s

45 Figure 4.29. Bode plots of (a) roll angle and (b) pitch angle response, for

k )

different values of the suspension stiffness coefficients ( s

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

46 Figure 4.30. Bode plots of (a) front-left suspension travel and (b) front- left wheel acceleration response, for different values of the

k ) and constant value of

suspension stiffness coefficients ( s the suspension damping coefficients ( c = 900 Ns / m ) ....... s

47 Figure 4.31. Bode plots of (a) front-right suspension travel and (b) front- right wheel acceleration response, for different values of the suspension stiffness coefficients ( k ) and constant value of s the suspension damping coefficients ( c = 900 Ns / m ) ....... s

48 Figure 4.32. Bode plots of (a) rear-left suspension travel and (b) rear-left wheel acceleration response, for different values of the suspension stiffness coefficients ( k ) and constant value of s

c = 900 Ns / m the suspension damping coefficients ( ) ....... s

49 Figure 4.33. Bode plots of (a) rear-right suspension travel and (b) rear- right wheel acceleration response, for different values of the

k ) and constant value of

suspension stiffness coefficients ( s the suspension damping coefficients ( c = 900 Ns / m ) ....... s

50 Figure 4.34. Peak-to-Peak values of (a) body displacement and (b) body acceleration response, for different values of the suspension stiffness coefficients ( k ) and constant value of the s suspension damping coefficients ( c = 900 Ns / m ) ............. s

51 Figure 4.35. Peak-to-Peak values of (a) roll angle and (b) pitch angle response, for different values of the suspension stiffness coefficients ( k ) and constant value of the suspension s

c = 900

damping coefficients ( Ns / m ) ............................... s

52 Figure 4.36. Peak-to-Peak values of (a) front-left suspension travel and (b) front-left wheel acceleration response, for different

k ) and

values of the suspension stiffness coefficients ( s

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c =

constant value of the suspension damping coefficients ( s 900 Ns / m ) ...........................................................................

53 Figure 4.37. Peak-to-Peak values of (a) front-right suspension travel and (b) front-right wheel acceleration response, for different

k ) and

values of the suspension stiffness coefficients ( s constant value of the suspension damping coefficients ( c = s

Ns / m 900 ) ...........................................................................

54 Figure 4.38. Peak-to-Peak values of (a) rear-left suspension travel and (b) rear-left wheel acceleration response, for different

k ) and

values of the suspension stiffness coefficients ( s constant value of the suspension damping coefficients ( c = s 900 Ns / m ) ...........................................................................

55 Figure 4.39. Peak-to-Peak values of (a) rear-right suspension travel and (b) rear-right wheel acceleration response, for different

k ) and

values of the suspension stiffness coefficients ( s constant value of the suspension damping coefficients ( c = s 900 Ns / m ) ...........................................................................

56 Figure 4.40.

ISO 2631 “fatigue-decreased proficiency boundary”: vertical vibration limits as a function of frequency and exposure time [2] ..................................................................

58 Figure 4.41. Vehicle body acceleration due to road excitation in comparison with ISO ride comfort boundaries, for different

c ) and

values of the suspension damping coefficients ( s constant value of the suspension stiffness coefficients ( k = s 18000 N / m ) ........................................................................

59 Figure 4.42. Vehicle body acceleration due to road excitation in comparison with ISO ride comfort boundaries, for different values of the suspension stiffness coefficients ( k ) and s constant value of the suspension damping coefficients ( c = s

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Figure 4.43. Vehicle body acceleration due to road excitation in comparison with ISO ride comfort boundaries, under full

61

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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 s m = Sprung mass ............................................................................ (kg) yy

I = Pitch moment of inertia ........................................................... (kgm

2

) xx

I =

Roll moment of inertia ............................................................ (kgm

2

) 1

mu = Front-left unsprung mass ......................................................... (kg) 2 mu = Rear-left unsprung mass .......................................................... (kg) 3 mu = Rear-right unsprung mass ........................................................ (kg) 4 mu = Front-right unsprung mass ...................................................... (kg) 1 ks = Front-left suspension stiffness coefficient .............................. (N/m) 2 ks = Rear-left suspension stiffness coefficient ................................ (N/m) 3 ks = Rear-right suspension stiffness coefficient ............................. (N/m) 4 ks = Front-right suspension stiffness coefficient ............................ (N/m) 1 cs = Front-left suspension damping coefficient .............................. (N/m) 2 cs

= Rear-left suspension damping coefficient ............................... (N/m) 3 cs =

Rear-right suspension damping coefficient ............................. (N/m) 4

cs = Front-right suspension damping coefficient ............................ (N/m) f l = Side distance from center of gravity to the front axle ............. (m) r l = Side distance from center of gravity to the rear axle ............... (m) fl a = Frontal distance from center of gravity to the front-left axle .. (m) rl a = Frontal distance from center of gravity to the rear-left axle ... (m) rr a = Frontal distance from center of gravity to the rear-right axle . (m) fr a = Frontal distance from center of gravity to the front-right axle (m) 1

x = Sprung mass heavy displacement ............................................ (m)

2

x = Sprung mass pitch angular displacement ................................ (rad)

3

x = Sprung mass roll angular displacement ................................... (rad)

4 x

=

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

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5

x = Rear-left unsprung mass displacement .................................... (m)

6

x = Rear-right unsprung mass displacement ................................. (m)

7

x = Front-right unsprung mass displacement ................................ (m)

1 in x =

2

v = Vehicle longitudinal velocity .................................................. (m/s) Y v = Vehicle lateral velocity ............................................................ (m/s) l = Wheel base .............................................................................. (m) w

Length ..................................................................................... (m) x

L =

Widht ....................................................................................... (m)

B =

Height ...................................................................................... (m)

F = Force acting at vehicle body .................................................... (N)

H =

) s

Gravity ..................................................................................... (N/m

Front-left displacement input .................................................. (m) 2 in

g =

)

2

= Sprung mass acceleration ........................................................ (m/s



x = Rear-right displacement input ................................................. (m)

4 in

x = Front-right displacement input ................................................ (m)

RMS z . 1 = RMS value of the sprung mass displacement ......................... (m)  = Time ........................................................................................ (s) 1 z

Rear-left displacement input ................................................... (m) 3 in

x =

= Wheel track ............................................................................. (m)