MEMS Vibratory Gyroscopes (eBook)

Preface 7
Contents 9
Fundamentals of Micromachined Vibratory Gyroscopes 13
Introduction 14
1.1 The Coriolis Effect 14
1.2 Gyroscopes 15
1.3 The MEMS Technology 16
1.4 Micromachined Vibratory Rate Gyroscopes 17
1.5 Applications of MEMS Gyroscopes 19
1.6 Gyroscope Performance Specifications 19
1.7 A Survey of PriorWork on MEMS Gyroscopes 21
1.8 The Robustness Challenge 25
1.9 Inherently Robust Systems 26
1.10 Overview 27
Fundamentals of Micromachined Gyroscopes 28
2.1 Dynamics of Vibratory Rate Gyroscopes 28
2.2 Resonance Characteristics 36
2.3 Drive-Mode Operation 39
2.4 The Coriolis Response 40
2.5 Summary 53
Fabrication Technologies 54
3.1 Microfabrication Techniques 54
3.2 Bulk Micromachining Processes 63
3.3 Surface-Micromachining Processes 70
3.4 Combined Surface-Bulk Micromachining 74
3.5 CMOS Integration 75
3.6 Packaging 78
3.7 Summary 82
Mechanical Design of MEMS Gyroscopes 83
4.1 Mechanical Structure Designs 83
4.2 Linear Vibratory Systems 84
4.3 Torsional Vibratory Systems 97
4.4 Anisoelasticity and Quadrature Error 103
4.5 Damping 112
4.6 Material Properties of Silicon 117
4.7 Design for Robustness 118
4.8 Summary 120
Electrical Design of MEMS Gyroscopes 121
5.1 Introduction 121
5.2 Basics of Capacitive Electrodes 121
5.3 Electrostatic Actuation 123
5.4 Capacitive Detection 127
5.5 Capacitance Enhancement 130
5.6 MEMS Gyroscope Testing and Characterization 134
5.7 Summary 149
Structural Approaches to Improve Robustness 150
Linear Multi-DOF Architecture 151
6.1 Introduction 151
6.2 Fundamentals of 2-DOF Oscillators 152
6.3 The 2-DOF Sense-Mode Architecture 157
6.4 The 2-DOF Drive-Mode Architecture 166
6.5 The 4-DOF System Architecture 174
6.6 Demonstration of 2-DOF Oscillator Robustness 188
6.7 Summary 193
Torsional Multi-DOF Architecture 194
7.1 Introduction 194
7.2 Torsional 3-DOF Gyroscope Structure and Theory of Operation 196
7.3 Illustration of a MEMS Implementation 202
7.4 Experimental Characterization 208
7.5 Summary 213
Distributed-Mass Architecture 214
8.1 Introduction 214
8.2 The Approach 214
8.3 Theoretical Analysis of the Trade-offs 220
8.4 Illustrative Example 222
8.5 Summary 231
Conclusions and Future Trends 232
9.1 Introduction 232
9.2 Comparative Analysis of the Presented Concepts 233
9.3 Demonstration of Improved Robustness 234
9.4 Scale Factor Trade-off Analysis 239
9.5 Future Trends 243
9.6 Conclusion 252
References 253
Index 261