Keywords piezoelectric actuator equivalent circuit multilayer actuator bender Langevin transducer ultrasonic motor closed-loop control Chapter Outlineġ.1.1 Basic principle of a piezoelectric actuatorġ.3 Variability of the operating point of piezoelectric actuatorsġ.3.1.2 Saturation effect in an ultrasonic actuatorġ.4.2 Position control of piezoelectric actuatorsġ.4.3 Vibration control of ultrasonic actuators 1.1 What is a piezoelectric actuator? 1.1.1 Basic principle of a piezoelectric actuatorĪn actuator converts electrical energy into mechanical energy. The chapter ends with the basics of the control theory, which are used in later chapters to design controllers. The chapter also discusses the variability of the operating point of the piezoelectric actuators, and explains why a closed-loop control is needed. The basic principles of some widely used piezoelectric actuators and motors are presented, and illustrated with typical applications. Starting from the material, and describing its manufacturing process, we present several ways to exploit the energy conversion in order to obtain the displacement of a mechanical load. This chapter presents a preliminary overview of the state-of-the art in the field of piezoelectric actuators.
