<title>Piezoelectric actuators for dynamic applications</title>

Abstract

The main advantages of piezoelectrical actuators are their high resolution in motion and their excellent dynamic behavior. Especially the very short response time of solid state actuators presents new opportunities in developing high dynamical systems with unsurpassable characteristics. New concepts of piezoelectrically driven microoptical devices, e.g. optical fiber switches, intensity modulators and choppers, can be developed. Very compact systems with parallel motion and high accuracy can be realized by the integration of piezoelectrical actuators into special mechanical frames with solid state hinges. Due to the combination of piezoelectrical actuators and mechanical lever transmission systems decisive advantages compared with other actuation concepts can be obtained. Appropriate displacements can be reached with comparatively small sized and thus low capacitance actuators. Low capacitance actuators enable the use of efficient electrical amplifiers for high dynamics. The behavior of the mechanical system is equivalent to a spring-mass-oscillator with a high quality factor. Because of their high stiffness the resonance frequencies of piezoelectrical actuators are quite high, but parasitic oscillations can appear if the element is driven with unsteady electrical functions e.g. square-or triangle-functions. Unwanted oscillations can deteriorate the general characteristics of dynamic actuators or in worst cases they can cause mechanical break down. New hybrid piezoelectrical actuator systems for dynamical applications are presented. General aspects of improving the dynamics ofpiezoelectrical systems and different methods for adequate passive damping will be discussed in this paper.