Contents



Preface

Precision positioning is widely required in both scientific research and industrial application. Taking advantage of high resolution, rapid response, and compact structure, piezoelectric actuators are broadly employed for achieving precision positioning, for example, in the fields of precision machining and measurement, nanomechanical testing, atomic force microscopy (AFM), micromanipulation, and so on. To satisfy the increasing requirements in precision positioning, great efforts have been made to improve the performances of piezoelectric actuators. For example, more and more novel principles have been proposed to design piezoelectric actuators. With the development in the piezoelectric material, driving principle, structure design, and control strategy, the speed, positioning resolution/accuracy, loading capacity, working bandwidth, and stroke of piezoelectric actuators have been significantly improved, further enhancing their applications. Over eight chapters, this book discusses recent achievements and developments in the field.

Chapter 1 focuses on tuning the magnetoelectric coefficient in sintered piezoelectric– magnetostrictive composites by introducing some individual phases. It examines the effects of these introduced phases on the magnetoelectric coefficient, coercive field, saturation magnetization, magnetic permeability, piezomagnetic coefficient, and

Chapter 2 focuses on the parasitic motion principle (PMP) of piezoelectric actuators. This type of piezoelectric actuator has received more attention in recent years because of its simple structure, control, and flexible design. The chapter defines PMP as well as discusses its application in the design of piezoelectric actuators. It also presents the similarities and differences of PMP with two other types of stepping principles. Finally, the chapter considers recent developments in structural design and performance improvements of PMP piezoelectric actuators and points out existing issues

Chapter 3 discusses inchworm-type piezoelectric actuators, examining their motion principles, classification (linear, rotary, and multi-DOF), and development. It also

Chapter 4 focuses on the stick-slip piezoelectric actuator, which is very promising for achieving both long working stroke and high positioning resolution. In this chapter, the authors summarize their recent studies on this topic both on the structural design and driving method. In terms of structural design, the authors present various flexure hinge mechanisms, especially asymmetrical flexure hinges, to improve the performances of stick-slip piezoelectric actuators, for example, their velocity and loading capacity. In terms of driving methods, they also present a non-resonant mode smooth driving method (SDM) to suppress the backward motion, and a resonant mode SDM to improve the output performances. The authors present many solutions for improving the performances of stick-slip piezoelectric actuators.

Chapter 5 models piezoceramic actuators for potential applications in future control. It develops a full electro-mechanical model of piezoceramic actuators

more.

and future research directions.

examines the future directions of these actuators.

*by Sahil P. Wankhede and Tian-Bing Xu*
