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DESIGN, CONTROL, AND APPLICATION OF PIEZOELECTRIC ACTUATOR External-Sensing and Self-Sensing Actuator ANDI SUDJANA PUTRA NATIONAL UNIVERSITY OF SINGAPORE 2008 DESIGN, CONTROL, AND APPLICATION OF PIEZOELECTRIC ACTUATOR External-Sensing and Self-Sensing Actuator ANDI SUDJANA PUTRA (B.Eng., Brawijaya University, M.T.D., National University of Singapore) A THESIS SUBMITTED FOR THE DEGREE OF DOCTOR OF PHILOSOPHY DEPARTMENT OF ELECTRICAL AND COMPUTER ENGINEERING NATIONAL UNIVERSITY OF SINGAPORE 2008 Acknowledgements I would like to express my sincere appreciation to all who have helped me during my candidature; without whom my study here would have been very much different. First and foremost, I thank my supervisors: Associate Professor Tan Kok Kiong and Associate Professor Sanjib Kumar Panda, who have provided invaluable guidance and suggestion, as well as inspiring discussions. With their enthusiasm and efforts in explaining things clearly, they have made research a fun and fruitful activity. I would have been lost without their direction. I would also like to thank the National University of Singapore for providing me with scholarship and research support; without which it would have been impossible to finish my study here. It is difficult to overstate my gratitude to the officers and students in Mechatronics and Automation Laboratory, who have also become my friends. Dr. Huang Sunan, Dr. Tang Kok Zuea, Dr. Zhao Shao, Dr. Teo Chek Sing, and Mr. Tan Chee Siong have always been very supportive and encouraging through the easy and difficult time during my research. I am indebted to many more colleagues in Faculty of Engineering and Faculty of Medicine, whose names, regrettably, I cannot mention all here. Finally, my deepest gratitude goes to my family and close friends. I dedicate this thesis to you. i Contents Acknowledgements i Summary viii List of Tables ix List of Figures xiii 1 Introduction 1 1.1Motivation................................. 1 1.2ResearchObjectives............................ 5 1.3ScopeoftheThesis............................ 6 1.4Outline................................... 8 2 Literature Review and Background 10 2.1Piezoelectricity.............................. 10 2.2 Nonlinearity in Piezoelectric Actuator . 15 2.3 Design of Piezoelectric Actuator with Mechatronic Approach . 20 2.4 Control Issues in Relation to Piezoelectricity . 24 2.5 Mechanical Link for High-Precision Actuators . 27 2.6AdaptiveControl............................. 33 3 Design, Modeling, and Control of External-Sensing Piezoelectric Ac- tuator 36 ii 3.1Introduction................................ 37 3.2 Target Application: Intra-Cytoplasmic Sperm Injection (ICSI) . 42 3.2.1 GeneralProcedure........................ 43 3.2.2 Difficulties with Conventional/Manual ICSI . 46 3.2.3 Current Design of Piezo-Assisted ICSI . 48 3.3 Piezoelectric Actuator for ICSI . 50 3.3.1 Linear-Reciprocating Piezoelectric Actuator . 51 3.3.2 Partially-Rotating Piezoelectric Actuator . 52 3.4SystemModels.............................. 56 3.4.1 Linear-Reciprocating Piezoelectric Actuator . 57 3.4.2 Partially-Rotating Piezoelectric Actuator . 60 3.4.3 Dynamics of the Injection Needle . 65 3.5ControllerDesign............................. 66 3.6Results................................... 71 3.6.1 Linear-Reciprocating Piezoelectric Actuator . 71 3.6.2 Partially-Rotating Piezoelectric Actuator . 75 3.6.3 Comparison between Linear-Reciprocating and Partially-Rotating Piezoelectric Actuator . 78 3.6.4 ICSI Experiments and Cell Development . 81 3.7 Future Application with Iterative Learning Control . 83 3.7.1 Modeling of the Actuator . 84 3.7.2 Compensation with a Regulated Chatter . 88 3.7.3 Approximate Error Convergence Analysis . 92 3.7.4 SimulationStudy......................... 95 3.7.5 Experimental Results . 96 3.8Conclusion................................. 98 4 Design, Modeling, and Control of Self-Sensing Piezoelectric Actua- tor 107 iii 4.1Introduction................................ 108 4.2 Target Application Microdispensing System . 111 4.2.1 Working Principle of Microdispensing System . 112 4.2.2 Microdispensing System with X-Y Table . 114 4.2.3 Design Consideration . 114 4.3 Self-Sensing Actuation . 116 4.3.1 SSAMeasurement........................ 117 4.3.2 ErrorAnalysis........................... 120 4.4 Adaptive Control Scheme . 123 4.4.1 SystemModel........................... 123 4.4.2 Design of Controller . 124 4.5 Experiment, Results, and Discussions . 125 4.5.1 Experiment............................ 126 4.5.2 Comparison between SSA and ESA . 127 4.5.3 Comparison between PID with Adaptive Control and PID-Only Control.............................. 129 4.5.4 Results with Microdispensing System . 129 4.6FutureApplication............................ 129 4.6.1 WorkingPrinciple......................... 132 4.6.2 Device Description . 135 4.6.3 Design of the Device . 137 4.7Conclusion................................. 139 5 Conclusions 141 5.1Contribution................................ 141 5.2 Recommendation for Future Work . 143 Bibliography 145 Author’s Publications 160 iv Summary This thesis discusses the design, modeling, and control of piezoelectric actuator. Two major contributions are reported in the thesis: design of external-sensing actuator and design of self-sensing actuator. The major contribution of this thesis is that it offers a mechatronic approach in designing piezoelectric actuators. With the emergence of nanotechnology and along with the trend of product miniaturization, piezoelectric actuators are gaining increas- ing attention in the industry as well as in research community; and this emphasizes the importance of discussing this type of actuators in the field of research. Piezoelec- tric actuator exhibits nonlinear characteristics and, therefore, control of piezoelectric actuators constitute an integral part of it and is therefore an important subject, especially in the face of the high nonlinearity of piezoelectric actuators. The first major portions of this thesis are the design, modeling, and control of external-sensing actuator, with application in intra-cytoplasmic sperm injection (ICSI). The technique of external-sensing actuation (ESA) is the usual, ubiquitous technique used in closed-loop control systems, where a separate, independent sensor is used to provide information about the sensing variables to allow the implemen- tation of feedback control. The main discussion issues are the design steps of the proposed actuator and the control algorithm used to control the proposed actuator. The application area considered here, ICSI, is a biomedical application to perform an artificial fertilization. In this application, the sperm is to be injected into an oocyte (egg cell) so as to result in fertilization. A partially-rotating piezoelectric actuator is proposed in this application to provide an injection of the sperm into an oocyte v with minimum damage inflicted to the oocyte. A linear-reciprocating piezoelectric actuator is also presented as an alternative approach to accomplish the same task. As far as the application is concerned, the aim is to achieve blastocyst level of cell development with high survival rate. The second major contribution of this thesis are the design, modeling, and control of self-sensing actuator, with application in a microdispensing system. The technique of self-sensing actuation (SSA) is the implementation of a single component to func- tion as both an actuator and a sensor. This technique is not novel; in fact it has been around since 1990s and has been employed in several structures for vibration suppression. This thesis proposes a discussion in the comparison between ESA and SSA technique, especially in which condition one technique is better than the other, with detailed study for a system whose reference signal is a switching trajectory. Mi- crodispensing system, the application area considered here, is a type of manufacturing process that dispenses liquid in a minute volume and in a precise manner, typically of the order of microliter. In this thesis, a contacting and a non-contacting method of liquid dispensing are discussed; one is based on adhesive force principle and the other one is based on mass inertia principle. The aim is to produce patterns of droplets with uniform dimension. In addition to focusing on the comparison between ESA and SSA, the control system and design of the microdispensing system are also discussed. In the two systems discussed in both cases, adaptive controllers are employed to overcome the adverse effect of nonlinearity inherited by the piezoelectric actua- tor. The control system proposed in this thesis follows a scenario of combining a simple, linear controller to perform major task of trajectory tracking with a more complicated, non-linear controller to overcome the nonlinearity of the piezoelectric actuator. Adaptive controller is chosen because of its ability to overcome nonlinear- ity without high computational requirements and also because it does not require repetitive reference signal, among other things. Adaptive controller is mainly used here to overcome the hysteresis of the actuator, although it will also overcome other vi types of nonlinearity to a certain degree. As an additional note, the linear controller used in this thesis is a proportional-integral-differential (PID) controller. In applying the principle of mechatronic approach, especially in designing, the application area of the actuator has been considered since the initial stage of the design, along with the general structure

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