A new linear piezoelectric actuator for low voltage and large displacementapplications

In this work a piezoelectric actuator is described whose stator is composed of two cylindrical steel axes fitted at the surface of a thin piezoelectri c membrane. The slider is a beam pressed in contact with two rotors. Each r otor consists of a cylindrical permanent magnet, pressed in contact with th e top surface of each axis, by means of magnetic forces. A travelling wave, at the natural flexural vibration frequency of the thin piezoelectric memb rane, is excited via piezoelectric effect. The flexural displacement of the membrane is geometrically amplified by the axes, obtaining a wide precessi onal motion of the axes. The transmission mechanism of the proposed actuato r is based on this motion. The actuator is able to give large displacements with a relatively high linear speed(1.21 m/s) and force (0.51 N) by using a commercial piezoelectric membrane (diameter 32 mm, thickness 0.2 mm), dri ven at relatively low voltage (+/-18 V). The very small thickness of the ov erall structure makes this actuator suitable for microsystem applications. A simple analytical approach of the transmission mechanism is reported and experimental measurements are discussed. (C) 1999 Elsevier Science B.V. All rights reserved.