臺灣博碩士論文加值系統

摘 要

在本文中，為滿足旋轉的需求，研製混合式轉換器。此混合式的轉換器係由一組縱向壓電陶瓷振動器和一組扭轉壓電陶瓷振動器組成。研究主要重點是利用退化方法來搜尋縱向和扭轉兩組壓電陶瓷振動器之共振頻率，透過機構設計使其能使用同一驅動頻率。研究中發現藉由設計一個附著於扭轉壓電陶瓷振動器的模板，可以獲得一個範圍之共振頻率，如此可提供縱向和扭轉振動器多重選擇，依需求進行最佳化設計。
研究中將展示轉換器之結構設計及退化方法之範例。利用所建立之定子有限元素模型，藉使用ANSYS模擬縱向與扭轉振動器之共振頻率，且發現轉換器的輸出為一Lissajous圖形。此外，針對所搜尋之退化共振頻率範圍，利用數學模式計算定子及轉子之力矩及速度輸出，以獲得的最佳化設計之結果，並驗證其轉換器的功能。

Abstract

In this thesis, a hybrid transducer is built in order to provide rotation. A new design of hybrid transducer consisting of individual longitudinal and torsional vibrators is investigated. Degeneracy approach for searching the same resonant frequency of both the longitudinal and torsional ceramic vibrators is the primary task of hybrid transducer design. In this study, by using a template attached to the torsional ceramic vibrator, a range of degeneracy is found, which provides more possible configuration design of the longitudinal and torsional vibrators. A case study is presented to demonstrate the structure design and the approach of degeneracy. A FE model of stator is developed to simulate the resonance frequencies of longitudinal vibrator and torsional vibrator by using ANSYS. A Lissajous figure of the output of the transducer is found. Also, an optimal design of large torque and speed is achieved based on the searched range of degeneracy. With the determined driving frequency corresponding to different structure design of the longitudinal and torsional vibrators, simulation and analytical computation is carried out to verify the performance of the stator and rotor of the transducer.

Table of Contents

Chinese Abstract I
English Abstract II
Acknowledgements III
Table of contents IV
List of figures VII
List of tables X
Chapter 1: Introduction 1
1.1 Problem Statement 1
1.2 Literature Review 1
1.3 Objective 2
1.4 Research Contribution 3
1.5 Chapter Summary 4
Chapter 2: Piezoelectric effect and Characteristics 5
2.1 Piezoelectric effect 5
2.2 Piezoelectric ceramics 5
2.2.1 Definition of piezoelectric ceramics 5
2.2.2 Properties of piezoelectric ceramics 5
2.2.3 Application of piezoelectric ceramics 6
2.2.4 Characteristics of Piezoelectric Ceramics 6
Chapter 3: Overview of Piezoelectric Ultrasonic motor 11
3.1 History of ultrasonic motor 11
3.2 Operating principle of ultrasonic motor 13
3.3 Forming elliptical displacement motion 13
3.4 Classification of ultrasonic motor 15
3.4.1 Classification by excitation 15
3.4.2 Classification by motor construction 20
3.4.3 Classification by motor function 22
Chapter 4: Introduction of Longitudinal-Torsional Transducer 24
4.1 Hybrid transducer 24
4.1.1 Configuration and working principle 24
4.1.2 History of hybrid transducer 25
4.1.3 Degeneracy 27
4.2 Revolving vibrator type transducer 31
4.3 Sandwiched rotor type transducer 31
4.4 Equivalent circuit 32
Chapter 5: Improvement of degeneracy for Hybrid transducer 34
5.1 Introduction 34
5.2 Structure design 35
5.2.1 Working principle 35
5.2.2 Features and advantages 36
5.3 Simulation and results 36
5.4 Discussion 51
5.5 The range of degeneracy for higher modes 57
5.6 Conclusion 60
Chapter 6: Modeling and Simulation 61
6.1 Basic design considerations 61
6.2 Modeling 61
6.2.1 Design procedure 65
6.2.2 Selection of piezoelectric ceramic disk 70
6.2.3 Selection of elastic block 70
6.2.4 Selection of adhesive 70
6.2.5 Selection of friction material 70
6.3 Structure of prototype 71
6.4 Simulations 74
6.4.1 Model analysis 74
6.4.2 Harmonic analysis 75
Chapter 7: Conclusion and Future works 78
7.1 Conclusion 78
7.2 Future works 78
References 79

List of Figures


2.1 Polarization Processing of Piezoelectric Ceramics 6
2.2 Radial mode 7
2.3 Length mode 7
2.4 Longitudinal mode 8
2.5 Thickness mode 8
2.6 Shear mode 9

3.1 The basic construction of ultrasonic motors 12
3.2 Ultrasonic motors by Batch 12
3.3 Operating principle of an ultrasonic motor 13
3.4 Elliptical displacement motion 14
3.5 Construction of an ultrasonic motor 14
3.6 The operation principle of linear motor 15
3.7 An example of linear traveling wave USM [Ueha 1993] 16
3.8 An example of MCUM with a vibration piece 16
3.9 Longitudinal and torsional mode and their elliptic motion 17
3.10 Ultrasonic motor structures classified by vibrational modes 18
3.11 (a) Scheme of the mode rotation (b) Piezoelectric element with
divided electrode for the mode rotation 19
3.12 An example of HTUM [Ueha 1989] 20
3.13 Contact surface loci of the actuator at different vibration
amplitude ratios (a) low speed; (b) moderate speed; (c) high speed 20
3.14 Resonance modes and frequency constants of a disk in
bending vibration 21
3.15 Non-axisymmetric modes and excitation of two-phase drive 21
3.16 An annular plate ultrasonic motor using radial and
non-axisymmetric vibrations 21
3.17 Resonance modes of a flexural vibrating bar 22
3.18 Longitudinal and torsional modes and their elliptic motion 22
3.19 A rectangular plate motor using longitudinal and
bending vibrations 22
3.20 A rectangular plate motor using two bending vibrations 22

4.1 Configuration of the hybrid motor 25
4.2 Operating principle of hybrid motor 25
4.3 The first prototype hybrid transducer type ultrasonic motor 26
4.4 Second prototype hybrid transducer type ultrasonic motor 26
4.5 Third prototype hybrid transducer type ultrasonic motor 27
4.6 Degeneracy-mode motor by using a Exponential Horn 28
4.7 Degeneracy-mode motor by using a adjusting ring 29
4.8 Degeneracy-mode motor by abrupt reduction of cross-section in
the rod 29
4.9 Degeneracy-mode motor by using a Step-formed vibrator 30
4.10 Degeneracy-mode motor by using a hollow and short
cylindrical structure of stator with an inner adjusting ring 30
4.11 Revolving vibrator type motor 31
4.12 Sandwiched rotor type motor 32
4.13 Equivalent circuit 32
4.14 Model of friction characteristics 33

5.1 Structure of Transducer (iso view) 35
5.2 Structure of Transducer (Section view) 35
5.3 Piezoelectric ceramics for excitation of torsinal vibration 38
5.4 Piezoelectric ceramics for excitation of longitudinal vibration 38
5.5 Resonant frequency vs. length (longitudinal) 41
5.6 Resonant frequency vs. length (torsional) 41
5.7 Search of degeneracy 42
5.8 Torsional PZT disk and vibrator 44
5.9 Twist deformation of torsional vibrator 47
5.10 Torque, no-load speed, and efficiency vs. length L2 50
5.11 Modal analysis. (longitudinal vibrator) 52
5.12 Modal analysis (torsional vibrator) 53
5.13 Harmonic response – z direction 53
5.14 Harmonic response – z direction 54
5.15 Harmonic response – y direction 54
5.16 Boundary conditions for torsional vibration 55
5.17 Boundary conditions for longitudinal vibration 56
5.18 Longitudinal amplitude – z direction 56
5.19 Transverse amplitude – x direction 57
5.20 Transverse amplitude – y direction 59
5.21 A Lissajous figure by combining the longitudinal, transverse and
radial amplitude 59
5.22 Resonant frequency vs. length (longitudinal), second mode 60
6.1 Basic structure of the hybrid ultrasonic motor 62
6.2 Model of the preload waveform 63
6.3 Longitudinal wave and contact situation 65
6.4 Torsional PZT disk 66
6.5 Torsional PZT disk and vibrator 66
6.6 ISO view of prototype 72
6.7 ISO view of prototype and it holder 72
6.8 Cross-section view of prototype 73
6.9 Prototype 20 73
6.10 Assembled view of prototype 74
6.11 Modal analysis (longitudinal vibrator) 75
6.12 Modal analysis (torsional vibrator) 75
6.13 Harmonic response – z direction 76
6.14 Harmonic response – x direction 76
6.15 Harmonic response – y direction 77

List of Tables


5.1 Material properties of prototype 37
5.2 Resonance frequency of Longitudinal Vibrator, first mode 39
5.3 Resonance frequency of Torsional Vibrator, first mode 40
5.4 Material Properties and Dimensions 48
5.5 Output torque and velocity of Torsional Vibrator 49
5.6 Output torque and No-load speed of rotor 49
5.7 Resonance frequency of Longitudinal Vibrator, second mode 57
5.8 Resonance frequency of Torsional Vibrator, second mode 58

6.1 Physical properties of adhesive 70

References

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