Development of a Hybrid Linear Actuator

132 Pages·2011·3.35 MB·English

Development of a Hybrid Linear Actuator
by
Baoping Wen
A thesis submitted in conformity with the requirements
for the degree of Master of Applied Science
Mechanical and Industrial Engineering
University of Toronto
©Copyright Baoping Wen 2011
Development of a Hybrid Linear Actuator

Baoping Wen
Master of Applied Science
Mechanical and Industrial Engineering
University of Toronto
2011
Abstract
This thesis focuses on the development of a novel hybrid linear actuator (HLA). The
research includes the optimal design, the particular fabrication, and the experimental validation.
The principle of the HLA is based on the integration of the mechanisms of the solenoid actuator
and the voice coil actuator. Such integration is achieved by a magnetic circuit consisting of a
magnetic flux orientator, a permanent magnet, a composite shell, and a special coil. The HLA is
capable of having a high repelling force at one end and a high attractive force at another end. A
step-optimization technique is developed and used to determine the key parameters of the HLA,
with the aid of sweeping functions in finite element analysis. Moreover, a single-pulse power
supply is specially designed and prototyped for driving the HLA. The performance of the HLA is
systematically characterized by simulations and experiments.

ii
To my Mom and Dad,
My dear wife, Wendy Wang,
My lovely daughter, Mei, and my son, Marcus

iii
Acknowledgments
I would like to express my gratitude to my advisor, Professor Jean W. Zu, for her full support
and guidance throughout my graduate life. Professor Zu’s patience and encouragement bolstered
my confidence and fueled my excitement in my work. Under her mentorship, I have grown as a
researcher and gradually become much more competent. I am grateful for Professor Zu, as she
provided a research platform which helped me integrate my personal interests and social
demands.
I would also like to thank Mr. Mats Lipowski and Mr. Anthony Wong, engineers from Vicicog
Inc., for providing the design requirement of the actuator and relevant information for the
synchronized segmentally interchanging pulley transmission system (SSIPTS) project.
My gratitude belongs to my labmates, Mr.Vahid Mashatan, Ms. Maby Boado, Mr. Wei-Jun Su,
Mr. Yang Zhu and Ms.Roshanak Banan, as well. Vahid provided his continuing support in the
control design of the experiment set-up. Maby and Wei-Jun gave their sincere suggestions on the
format of thesis writing. Yang presented his useful ideas in graphing, and Roshanak offered her
valuable proof-reading for the draft version.
I also present my sincere appreciation to Mr. Ryan Mendell, manager of the MIE machine shop
in University of Toronto, for providing the convenience and help in the fabrication of the
actuator prototyping.
I would like to thank Professor James K. Mills and Professor Yu Sun for serving on my thesis
committee and offering their generous comments during their busy academic activities.

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Table of Contents

Acknowledgments .......................................................................................................................... iv
Table of Contents ............................................................................................................................ v
List of Tables ................................................................................................................................. ix
List of Figures ................................................................................................................................. x
List of Appendices ....................................................................................................................... xiv
List of Symbols, Abbreviations and Nomenclature ...................................................................... xv
Chapter 1 Introduction ............................................................................................................. 1
1.1 Background and Motivation ............................................................................................... 1
1.2 Requirements of the New Actuator ..................................................................................... 3
1.3 Objectives ........................................................................................................................... 4
1.4 Thesis Overview ................................................................................................................. 4
Chapter 2 Literature Review .................................................................................................... 6
2.1 Overview of Actuators ........................................................................................................ 6
2.1.1 Classification of Actuators ...................................................................................... 6
2.1.2 Characterization of Actuators ................................................................................. 7
2.2 Electromagnetic Actuators .................................................................................................. 9
2.2.1 Nature of Magnetic Interactions ............................................................................. 9
2.2.2 Principles of Electromagnetic Actuators .............................................................. 13
2.2.3 Advantages of Electromagnetic Actuators ............................................................ 15
2.3 Improvement of Electromagnetic Actuators ..................................................................... 15
2.3.1 Efficient Magnetic Circuit Configurations ........................................................... 16
2.3.2 Improvement of Material Properties ..................................................................... 17
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2.3.3 Optimal Design of Magnetic Field ....................................................................... 20
2.3.4 Inspiration from Electromagnetic Catapult ........................................................... 21
Chapter 3 Conceptual Design ................................................................................................ 22
3.1 Global Geometric Constraints of Actuators in SSIPTS .................................................... 22
3.2 Speed Constraints of SSIPTS ............................................................................................ 24
3.3 Magnetic Circuit Design ................................................................................................... 28
3.3.1 Concept of Magnetic Circuit ................................................................................. 28
3.3.2 Physics of Electromagnetic Actuators .................................................................. 29
3.3.3 Comparison of Magnetized Direction ................................................................... 30
3.4 Structural Design of the Novel Actuator .......................................................................... 33
3.4.1 Parameterized Geometry Design .......................................................................... 33
3.4.2 Material Selections ................................................................................................ 36
3.5 Summary ........................................................................................................................... 37
Chapter 4 Modeling and Simulation ...................................................................................... 38
4.1 Basic Electromagnetism .................................................................................................... 38
4.1.1 Maxwell’s Equations ............................................................................................ 38
4.1.2 Constitutive Relations ........................................................................................... 40
4.1.3 Boundary and Interface Conditions ...................................................................... 40
4.1.4 Electromagnetic Energy ........................................................................................ 41
4.1.5 Electromagnetic Forces ......................................................................................... 42
4.2 Setup of Finite Element Analysis ..................................................................................... 44
4.2.1 FEA Expression of Electromagnetic Problems ..................................................... 44
4.2.2 Geometrical Modeling of the Actuator in FEA .................................................... 46
4.2.3 Physics Setting of Model Domains ....................................................................... 47
4.2.4 Meshing of the FEA Model .................................................................................. 51
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4.2.5 Solver Setting ........................................................................................................ 53
4.3 Optimization of the Actuator Design ................................................................................ 54
4.3.1 Optimization of Magnet Thickness ....................................................................... 54
4.3.2 Optimization of Magnet Length ............................................................................ 56
4.3.3 Optimal Combination of Shell Materials .............................................................. 58
4.4 Performance Characterization of the HLA ....................................................................... 60
4.4.1 Force Output Distribution vs. Coil Current and Coil Position .............................. 60
4.4.2 Predicted Specific Behaviors of the HLA ............................................................. 61
4.5 Reliability Assessment of the Simulation ......................................................................... 64
4.5.1 Comparison of Force Calculation in Different Methods ...................................... 64
4.5.2 Validation of the MotiCont Voice Coil Actuator ................................................. 66
4.6 Summary ........................................................................................................................... 68
Chapter 5 Fabrication ............................................................................................................ 69
5.1 Constructions of the Magnetic Assembly ......................................................................... 69
5.1.1 Integrity of the Properties of the Magnetic Materials ........................................... 69
5.1.2 Integrity of Magnetic Circuits ............................................................................... 71
5.2 Coil Winding ..................................................................................................................... 73
5.2.1 Filling Factors of Conductors in a Coil Window .................................................. 73
5.2.2 Coil Calculation .................................................................................................... 74
5.2.3 Bobbin Machining ................................................................................................ 75
5.3 Final Prototypes ................................................................................................................ 76
5.4 Summary ........................................................................................................................... 77
Chapter 6 Design and Fabrication of the Pulse Power Supply .............................................. 78
6.1 Requirements in Driving the New Actuator ..................................................................... 78
6.2 Design and Construction of the Pulse Power Supply ....................................................... 79
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6.3 Summary ........................................................................................................................... 82
Chapter 7 Experiment ............................................................................................................ 83
7.1 Experiment Set-up ............................................................................................................ 83
7.1.1 Experiment Jigs and Fixtures ................................................................................ 83
7.1.2 Experimental System Configuration ..................................................................... 85
7.1.3 Force Sensor Calibration ....................................................................................... 87
7.2 Data Collection and Analysis ............................................................................................ 88
7.2.1 Magnetic Force Variations over Coil Current and Coil Position .......................... 88
7.2.2 Magnetic Force Variations over Soft Magnetic Materials .................................... 93
7.2.3 More Strict Comparisons between Simulation and Experiment ........................... 95
7.2.4 Variations of Coil Inductances .............................................................................. 98
7.2.5 Actuation Time Prediction .................................................................................. 100
7.2.6 Comparison of the New Actuator with Commercial Products ........................... 101
7.3 Summary ......................................................................................................................... 102
Chapter 8 Conclusions and Future Work ............................................................................ 103
8.1 Conclusions ..................................................................................................................... 103
8.2 Applications .................................................................................................................... 104
8.3 Future Work .................................................................................................................... 104
Appendices….. ............................................................................................................................ 111

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List of Tables
Table 2-1: Actuator Classification by Energy Input ....................................................................... 7
Table 2-2: Properties of Different Hard Magnetic Materials ........................................................ 19
Table 3-1 Output Force Demand of the Actuator Regarding Different Rotating Speed .............. 27
Table 3-2: Analogous Comparison of the Magnetic Circuit and the Electrical Circuit ................ 28
Table 3-3: Parameterized Dimensions in SolidWorks Model ...................................................... 34
Table 3-4: Parameterized Dimensions in SolidWorks Model (continued) ................................... 35
Table 4-1: Parameter List for Geometric Modeling of the New Actuator .................................... 47
Table 4-2: Partial Differential Equations (PDEs) and Constitutive Equations of Domains ......... 48
Table 4-3: Functions of Soft Magnetic Materials (CoNetic AA and Netic S3-6) ........................ 50
Table 4-4: Solvers with Corresponding Features .......................................................................... 53
Table 4-5: Force Comparison for Different Calculation Means and Different Meshing Sizes .... 64
Table 4-6: Performance Data from Simulation and Datasheet of MotiCont Linear VCA ........... 67
Table 5-1: Numbers of Turns of Coil Calculation ........................................................................ 74
Table 5-2: Physical Parameters under Fabrication ....................................................................... 76
Table 7-1: Load Cell FC2231 Calibration .................................................................................... 87
Table 7-2: Performance Comparison with Commercial Products .............................................. 101

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List of Figures
Figure 1-1: Gear Shift in SSIPTS Transmission System ................................................................ 2
Figure 1-2: The Geometric Constraint of Actuators in SSIPTS Package ....................................... 3
Figure 2-1: Capacity of Actuators Characterized by Force vs. Stroke ........................................... 8
Figure 2-2: Agility of Actuators Characterized by Frequency vs. Weight ..................................... 9
Figure 2-3: Origin of Magnetism at Atomic Level ....................................................................... 10
Figure 2-4: Responses of Different Materials to the Same Magnetic Field ................................. 11
Figure 2-5: Interaction of Two Magnetic Fields Built Up by Direct Currents ............................. 12
Figure 2-6: Principle of Voice Coil Actuator Governed by Lorentz’s Law ................................. 13
Figure 2-7: Principle of Solenoid Actuator Governed by Variable Reluctance ........................... 14
Figure 2-8: Halbach Cylinders with Different Wavenumbers (k) ................................................ 16
Figure 2-9: Focus Effect of Magnetic Flux in the New VCA (Courtesy of BEI Kimco) ............. 17
Figure 2-10: Properties of Advanced Soft Magnetic Materials .................................................... 18
Figure 2-11: Properties of Hard Magnetic Materials .................................................................... 19
Figure 2-12: Thrust Force Improvement by Composite Coil Conductors .................................... 20
Figure 2-13: Catapult Force (Strong Field Interaction) ................................................................ 21
Figure 3-1: Geometric Constraints of Actuators in SSIPTS ......................................................... 22
Figure 3-2: Layout of Actuators in SSIPTS .................................................................................. 23
Figure 3-3: Space Using Efficiency of Different Cross-Section Shape of Actuators ................... 24
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