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UNIVERSITI PUTRA MALAYSIA

DESIGN AND SIMULATION OF A HIGH THRUST LINEAR OSCILLATORY

ACTUATOR

ALIAS KHAMIS

T FK 2007 40

DESIGN AND SIMULATION OF A HIGH THRUST LINEAR OSCILLATORY ACTUATOR

By

ALIAS KHAMIS

Thesis Submitted to the School of Graduates Studies, Universiti Putra Malaysia, in Fulfilment of the Requirements for the Degree of

Master of Science

October 2007

Abstract of thesis presented to the Senate of Universiti Putra Malaysia in fulfilment of the requirement for the degree of Master of Science

DESIGN AND SIMULATION OF A HIGH THRUST LINEAR OSCILLATORY ACTUATOR

By

ALIAS KHAMIS

October 2007 Chairman: Norhisam Misron, PhD Faculty: Engineering

An actuator is widely used in many applications either in automation, transportation,

productions, robotics, logistics, etc. There are many types of actuator available in the

market. An actuator is a device that converts energy into limited mechanical motion.

The form of energy could be electric, hydraulic or pneumatic. Electric actuator is

much superior compare to other energy form. It gives efficiency, controllability, cost

and environmental safety.

This thesis is a study on designing a linear oscillatory actuator based on

electromagnetic theory. The aim of this study is to develop a linear oscillatory

actuator for mechanical cutter with high thrust. Linear oscillatory actuator (LOA) is a

type of linear actuator whereby its motion is in single axis and moves continuously.

In this research, the design starts from magnetic analysis using Finite Element

Method (FEM). This software can simulate the flux density, flux flow, thrust,

cogging force, normal force on the element and material in the motor including

electromagnet element. The LOA was designed to have a view of its structure before

simulate the design by Microcal Origin software. Then, simulation was done to

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obtain the best thrust, cogging force and normal force value. Few modifications on

the structure are done during this simulation to identify the highest thrust, lowest

cogging force and normal force.

Simulations of all designed modelling are compared. Future recommendation has

been provided to help other researcher for further development of this LOA.

Abstrak tesis yang dikemukakan kepada Senat Universiti Putra Malaysia sebagai memenuhi keperluan untuk ijazah Master Sains

REKABENTUK DAN SIMULASI DAYA TINGGI PENUMATIK AKTUATOR LELURUS

Oleh

ALIAS KHAMIS

Oktober 2007

Pengerusi: Norhisam Misron, PhD Fakulti: Kejuruteraan

Aktuator digunakan secara meluas untuk pelbagai jenis aplikasi termasuk automasi,

pengangkutan, pengeluaran, robotik, logistik dan lain-lain. Terdapat pelbagai jenis

aktuator di pasaran. Aktuator ialah alat yang menukarkan tenaga tertentu kepada

tenaga mekanikal dalam bentuk yang terhad. Tenaga-tenaga ini mugkin elektrik,

haudrilik atau penumatik. Aktuator elektrik lebih baik berbanding dari jenis lain. Ia

memberikan kecekapan yang tinggi, keboleh kawalan, kos yang rendah and selamat

untuk alam sekitar.

Kajian ini adalah mengenai penciptaan sebuah penumatik aktuator lelurus

berdasarkan teori eletromagnetik. Tujuan kajian ini adalah untuk menghasilkan

sebuah aktuator penghayun linear (LOA) untuk pemotong mekanikal dengan daya

yang tinggi. Aktuator penghayun linear adalah merupakan salah satu jenis aktuator

linear di mana pergerakannya dalam satu paksi dan berterusan. Dalam penyelidikan

ini, rekaan bermula dengan analisis magnet menggunakan Finite Element Method

(FEM). Program ini dapat melakukan simulasi ketumpatan fluk, aruhan fluk, daya,

daya cogging, daya normal terhadap elemen dan bahan termasuk elemen

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elektromagnet. LOA perlulah dilukiskan terlebih dahulu untuk melihat strukturnya

sebelum membuat simulasi struktur tersebut menggunakan Microcal Origin program.

Kemudian, simulasi dijalankan untuk mendapatkan daya yang terbaik, daya cogging

dan daya normal. Beberapa pengubahsuaian dilakukan pada struktur dalam simulasi

untuk mengenal pasti daya yang paling tinggi, daya cogging dan daya normal yang

paling rendah.

Keputusan secara simulasi bagi semua rekaan dibandingkan. Cadangan untuk projek

pada masa akan datang juga dibincangkan untuk membantu para penyelidik

membangunkan aktuator elektrik lelurus yang lebih baik.

ACKNOWLEDGEMENTS

I would like to express my deepest appreciation and gratitude to my supervisor, Dr.

Norhisam bin Misron and my co-supervisor, Dr. Senan Mahmod for their valuable

advice, guidance, support and encouragement throughout this project. Their

suggestions always inspire me to produce good quality work.

Besides that, I would like to take this opportunity to express my gratitude to the

panel examiners, Prof. Madya Dr. Ishak Aris, Prof. Ir. Dr. Norman Mariun and Prof.

Ir. Dr. Abdul Halim Mohamed Yatim for their effort not only in marking and

correcting my thesis but for their advice that lead me to further improve my project.

I would like to express my heartfelt thanks to all my course mates and friends, whom

have shown their caring side in helping me searching for the information and

exchange of ideas. This has greatly helped with my confidence in completing the

project.

Furthermore, I would like to say special thanks to Universti Teknikal Kebangsaan

Malaysia for their kindness in sponsoring my further study in Master’s Research

until finish my studies.

Lastly, deepest thanks to my family for their support and care in making this research

report a masterpiece effort.

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I certify that an Examination Committee met on 11th October 2007 to conduct the final examination of Alias Khamis on his Master of Science thesis entitled “Design and Simulation of a High Thrust Linear Oscillatory Actuator” in accordance with Universiti Pertanian Malaysia (Higher Degree) Act 1980 and Universiti Pertanian Malaysia (Higher Degree) Regulations 1981. The Committee recommends that the student be awarded the relevant degree of Master of Science. Member of the Examination Committee are as follows: Syed Jabal Javaid Iqbal, PhD Lecturer Faculty of Engineering Universiti Putra Malaysia (Chairman)

Ishak Aris, PhD Associate Professor Faculty of Engineering Universiti Putra Malaysia (Internal Examiner)

Ir. Norman Mariun, PhD Professor Faculty of Engineering Universiti Putra Malaysia (Internal Examiner)

Ir. Abdul Halim Mohamed Yatim, PhD Professor Faculty of Electrical Engineering Universiti Teknologi Malaysia (External Examiner) ______________________________________

HASANAH MOHD. GHAZALI, PhD Professor and Deputy Dean School of Graduates Sudies

Universiti Putra Malaysia

Date: 24 October 2007

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This thesis submitted to the Senate of Universiti Putra Malaysia and has been accepted as fulfilment of the requirement for the degree of Master of Science. The members of the Supervisory Committee are as follows:

Norhisam Misron, PhD Lecturer Faculty of Engineering Universiti Putra Malaysia (Chairman)

Senan Mahmod Bashi, PhD Associate Professor Faculty of Engineering Universiti Putra Malaysia (Member)

__________________________________

AINI IDERIS, PhD Professor/Dean School of Graduate Studies Universiti Putra Malaysia Date :

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DECLARATION

I hereby declare that the thesis is based on my original work except for quotations and citations which have been duly acknowledged. I also declare that it has not been previously or concurrently submitted for any other degree at UPM or other institutions. ________________________

ALIAS KHAMIS

Date: 2 October 2007

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TABLE OF CONTENTS

Page

ABSTRACT ii ABSTRAK iv ACKNOWLEDGEMENTS vi APPROVAL vii DECLARATION ix LIST OF TABLES xiii LIST OF FIGURES xiv LIST OF ABBREVIATIONS xviii

CHAPTER

1 INTRODUCTION 1 1.1 Introduction 1 1.2 Problem Statement 2 1.3 Aim and Objectives 3 1.4 Scope of Work 4 1.5 Thesis Outline 5

2 LITERATURE REVIEW 7 2.1 Introduction to Finite Element Method 7 2.1.1 Historical Background 7 2.1.2 Basic Concept of the Finite Element Method 8 2.2 Introduction to Linear Oscillatory Actuator 8 2.2.1 Linear Oscillatory Actuator 8 2.2.2 Concepts of Linear Oscillatory Actuator 9 2.2.3 Operation of Linear Oscillatory Actuator 10 2.3 Magnetic Circuit of LOA 12 2.3.1 Magnetic Potential 13 2.3.2 Magnetic Flux 13 2.3.3 Reluctance 14 2.3.4 Permeance 14 2.3.5 Leakage Flux 15 2.3.6 Fringing 16 2.4 Magnetic Flux on LOA 17 2.4.1 Magnetic Flux 17 2.4.2 Magnetic Circuit 19 2.5 Thrust of LOA 20 2.5.1 Lorentz Force Equation 20 2.6 Materials of LOA 22 2.6.1 Ferromagnetic materials 22 2.7 Summary 25

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3 METHODOLOGY 26 3.1 Calculation Using Finite Element Method (FEM) 26 3.1.1 Modeling 26 3.1.2 Element Calculation (Vmesh) 29 3.1.3 Magnetic Analysis 31 3.1.4 Result Display 32 3.1.5 Flowchart 34 3.2 Simulation Design of LOA 36 3.2.1 Design Slot Type of Linear Oscillatory Actuator (LOA1) 36 3.2.1.1 Changing the Height of Taper, Ht and Length of Taper Gap, Lt 38

3.2.2 Design Slot Type of Linear Oscillatory Actuator Different Pitch (LOA2) 39 3.2.2.1 Changing the Length of Taper Gap, Lt 43 3.2.2.2 Changing the LOA2 for Different Pitch 44 3.2.3 Design Slot Type of Linear Oscillatory Actuator Different Length of Taper Gap, Lt (LOA3) 45 3.2.3.1 Changing the Length of Taper Gap, Lt for Each Coil 48

3.3 Summary 49

4 RESULT AND DISCUSSION 50 4.1 Thrust Characteristic Slot Type of Linear Oscillatory Actuator (LOA1) 50 4.1.1 Analysis the High Taper, Ht and Length of Taper Gap, Lt 52 4.1.2 Combination Thrust Characteristic of LOA1 54 4.2 Thrust Characteristic Slot Type of Linear Oscillatory Actuator Different Pitch (LOA2) 59 4.2.1 Analysis the Length of Taper Gap, Lt 59 4.2.2 Combination Thrust Characteristic of LOA3 for Different Pitch 60 4.3 Thrust Characteristic Slot Type of Linear Oscillatory Actuator Different High of Taper Gap, Lt (LOA3) 62 4.3.1 Analysis the Length of Taper Gap, Lt for Each Coil 62 4.3.2 Combination Thrust Characteristic of LOA3 64 4.4 Comparison of Linear Oscillatory Actuator (LOA) 65 4.4.1 Thrust Characteristic of Linear Oscillatory Actuator (LOA) 65

4.5 Collected Data from Various Companies 68 4.5.1 Thrust Characteristic from Collected Data 69

4.5.2 Motor Constant Characteristic from Collected Data 73 4.5.3 Motor Constant Square Density Characteristic from

Collected Data 77 4.5.4 Analysis Combination for All Motor 81 4.6 Comparison LOA Simulation and Experiment 84 4.6.1 Parameter and Constructed of LOA 84 4.62 Thrust Characteristics between Simulation and Experiment of LOA 85 4.6 Summary 87

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5 CONCLUSIONS AND SUGGESTIONS FOR FUTURE WORKS 88 5.1 Conclusions 88 5.2 Suggestions 90

REFERENCES R1

APPENDICES A1

BIODATA OF THE AUTHOR B1

LIST OF PUBLICATION P1

LIST OF TABLES

Table Page 1.1 Analogy between a Magnetic Circuit and a Electric Circuit 17

4.1 Comparison slot type of LOA 67

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LIST OF FIGURES

Figure Page

2.1 Structure of LOA 10

2.2 Magnetization of moving yoke 11

2.3 Movement of moving shaft to left 11

2.4 Movement of moving shaft to right 12

2.5 Leakage Flux 15

2.6 Fringing at air gap 15

2.7 Flow of flux when no current supply to coil 18

2.8 Flow of flux when current is applied 18

2.9 Representation of LOA in magnetic circuit 19

2.10 Representation of LOA in electric circuit 20

2.11 Lorentz Force 21

2.12 Ferromagnetic material 23

2.13 Hysterisis loop 24

3.1 Designed motor model in Microcal Origin 27

3.2 msk file 27

3.3 blk file 28

3.4 bod file 28

3.5 Mesh calculation 29

3.6 fra file 30

3.7 FEM calculation 30

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3.8 Element in the designed motor model using Cygwin 31

3.9 Config file 32

3.10 Result display of the designed motor 34

3.11 Flowchart of Simulation process using FEM 35

3.12 Flowchart of designing process of LOA1 37

3.13 Changing the length of taper gap 38

3.14 Changing the height of taper 39

3.15 Thrust characteristic for different pitch 41




3.19 Thrust characteristic of LOA3 46



4.1 Combination of graphs showing thrust force against the displacement 51

4.2 Combination of graphs showing cogging force against the displacement 51

4.3 Combination of graphs showing thrust against the high of taper gap 52

4.4 Combination of graphs showing cogging force against the high of taper gap 52

4.5 Combination of graphs showing thrust against the length of taper gap 53

4.6 Combination of graphs showing cogging force against the length of taper gap 53

4.7 Maximum thrust and cogging force with changes in the length of gap Lt and

high of taper, Ht 56

4.8 Maximum thrust of graphs showing thrust against the displacement 58

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4.9 Minimum cogging of graphs showing cogging force against the displacement 58


4.11 Minimum cogging of graphs showing cogging force against the displacement 60


4.13 Minimum cogging ion of graphs showing cogging force against the

Displacement 61

4.14 Maximum thrust of graphs showing thrust force against the displacement 63


4.16 Combination of graphs showing thrust against the displacement 64


4.18 Combination of graphs showing thrust force against the displacement 66


4.20 Thrust characteristic for Mire company 69

4.21 Thrust characteristic for Trilogy company 70

4.22 Thrust characteristic for H2W technology company 71

4.23 Thrust characteristic for Rockwell company 72

4.24 Motor Constant characteristic for Mire company 73

4.25 Motor Constant characteristic for Trilogy company 74

4.26 Motor Constant characteristic for H2W technology company 75

4.27 Motor Constant characteristic for Rockwell company 76

4.28 Motor constant square density characteristic for Mire company 77

4.29 Motor constant square density characteristic for Trilogy company 78

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4.30 Motor constant square density characteristic for H2W technology company 79

4.31 Motor constant square density characteristic for Rockwell company 80

4.32 Combination of graphs showing thrust against the size of motor 81

4.33 Combination of graphs showing motor constant against the size of motor 82

4.34 Combination of graphs showing motor constant square density against the

size of motor 83

4.35 Parameter of LOA on Simulation and Constructed 84

4.36 Constructed of LOA 85

4.37 Thrust characteristic from experiment data collected 86

4.38 Comparison between simulation and experiment thrust characteristics 86

LIST OF ABBREVIATIONS

Nd-Fe-B Neodymium-Iron-Boron

N North Pole

S South Pole

J Current Density

F Thrust or Force

N Number of Turns

I Current

B Magnetic Field

ℓ Length of Coil

d Displacement

g Vibration

a Acceleration

v Voltage

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CHAPTER 1

INTRODUCTION

1.1 Introduction

In this modern day, there are many types of motor available in the market. More

special characteristics of motor needed in motor such as high efficiency, small, low

weight, produce high thrust and high speed, high precision and others related

function. In Malaysia, local industries usually obtain the motor from foreign

manufacture. This is due to limited knowledge and technology in the development of

the motor [M.Norhisam, 2004].

Basically, rotary motor is always use in industrial application. This rotary motion can

be converted to linear motion using belt, gears and screw. For instance, conveyer

transports good in a factory. Only two motors can be used instead of a few motor

along the conveyer. This method can save cost but for long term, higher maintenance

cost and loss of torque due to the use of gear/belt has made it not competitive.

Besides, for certain application where high precision position and speed along the

conveyer is needed, linear motor is the suitable solution [Syed A. Nasar, 1997].

An actuator is a device that may produce small displacement when in operation.

Therefore an actuator can use pneumatic or hydraulic principle to operate. Electrical

energy also can be used to operate actuator by using electromagnetic principle. An

electric linear electrical actuator is a device that converts electric energy to

mechanical motion of limited travel with the help of electromagnetic principle.

Electric actuator is much superior to pneumatic or hydraulic actuator in terms of

efficiency, controllability, cost and environmental safety. Nowadays, electricity is

available anywhere and even at home.

1.2 Problem Statement

Oil palm motorized cutter introduced by Malaysian Palm Oil Berhad (MPOB) has

emerged new era for palm oil industries. It uses 2 stroke petrol engines to supply

mechanical energy to a shaft which is bonded with a C shape blade. It has total

weight of 6.2 kg and length 3.6 meter. There is a shaft along the rod towards the C

shape blade. If the rod length increased, the rod will bend down due to its gravity

stability point is out of range. This problem occurred when motorized cutter is used

for adult palm oil trees. Adult palm oil trees can achieved 10 meters of height [Abdul

Razak J., June 1999].

Therefore, designing an electrical cutter may solve the height problem since only

wires and no shaft is required along the rod. Linear actuator is the suitable device

which produces small displacement in double axis direction. This actuator will be

coupled with a C shape blade. When linear actuator operates, it would make a certain

displacement on the C shape blade. This blade will move forward and backward. At

high frequency, this C shape blade will only vibrate. This will give smooth cutting

shape to the palm. The electric source to the actuator will be supplied by a generator.

These projects only focus on the development of the linear actuator.

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This linear motor was designed to be used as palm mechanical cutter. It will produce

a linear motion where the shaft will move forward and backward. At the end of the

shaft, there is a C-curve blade. Therefore, the linear motion will make this C-curve

blade to move up and down. First, a study has been conducted in searching any other

previous mechanical cutter available in market. Then, linear motor was studied based

on the theory to obtain the best design method. It was found that linear motor is

suitable for these purposes.

The design starts from magnetic analysis using Finite Element Method (FEM). It is

used to solve partial differential equations (PDE) approximately. This software can

perform simulation on element and material of the motor. This includes

electromagnet element such as flux density, vector, magnetic field etc.

1.3 Aim and Objectives

The aim of this project is to design basic structure of the electric linear actuator for

the palm mechanical cutter. The objectives of this project are design, simulation and

analyze a linear actuator with high thrust for performance study.

The objectives of this study are:

to propose a basic operation of Linear Oscillatory Actuator for mechanical

cutter,

to design a Linear Oscillatory Actuator,

to understand the characteristic of Linear Oscillatory Actuator based on the

design conducted,

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to compare the characteristics of Linear Oscillatory Actuator based on the

simulation findings, and

to choose the best design of Linear Oscillatory Actuator based on the thrust

characteristics findings

1.4 Scope of Work

In this project, the design of linear oscillatory actuator is based on the principles of

magnetic circuits. By generating forces to attract the moving yoke periodically on

both sides of the yoke, oscillating effect can be produced. Similarly as a linear motor,

linear oscillatory actuator movement is small and continuously repeated both ways

linearly.

This project can be divided into few stages. The first stage is the study of the basic

principal of Linear Oscillatory Actuator (LOA). Once the principal of LOA is

understood, the designing stage of LOA can be started. This process is mostly

performed on the computer where modelling and Finite Element Method (FEM)

simulation software are used. Parameters of the design will be varied in order to

obtain the best performance of the motor.

Once this is completed, the next stage is to compare the thrust characteristic based on

different design and simulation of the motor. The best performance of thrust

characteristic of the motor has been chosen. The motor can be designed for the

further development based on the good selection of motor.

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After this stage, the performance of the motor has been finalised. From the data

obtained, the simulated characteristic of the motor can be obtained.

1.5 Thesis Outline

The first chapter will discuss a brief introduction of the project undertaken here. The

aim and objectives has been listed out. Furthermore, this chapter will briefly mention

about the outline of the project.

Chapter Two will be discussing about the literature presented. In this chapter, the

concept of Linear Oscillatory Actuator (LOA) will be mentioned. The operation wise

of the LOA will be explained here. Studies about magnetic theories, magnetic flux

and magnetic circuit’s concepts will be discussed. The magnetic circuit of the LOA

will be discussed along with its representation in electrical circuit terms. The

characteristic of the ferromagnetic material used in fabrication will be mentioned

briefly.

Methodology of the project will be mentioned in chapter Three. The procedures or

steps to complete the project will be discussed in detail. Simulation techniques used

will be discussed in this chapter. Then the design of LOA can be finalised. The

structure of LOA is produced based on the design. Then the design will be subjected

simulated that determine the thrust performance will be discussed.

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Chapter Four will present the result and discussion of the comparisons performed.

The data of the comparison will be tabulated in this chapter. Explanation of the

characteristic based on the simulations result will be discussed.

The last chapter will be the conclusion. All other future suggestions and

recommendation are mentioned here. Hopefully all the opinions and ideas will

provide benefits for future studies.

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