A novel standing wave linear piezoelectric actuator using the longitudinal-bending coupling mode

Abstract

A novel standing wave linear piezoelectric actuator is proposed and tested by using a sandwich transducer operated in longitudinal-bending coupling mode. The vibration mode used in this work is neither longitudinal mode nor bending mode, but a longitudinal-bending hybrid one, which is generated simultaneously by only one group of PZT ceramic elements. The exciting principle of this coupling mode is discussed, and then realized by designing a standing wave piezoelectric actuator. When the 1st longitudinal and 3rd bending modes of the transducer have colse resonance frequencies and unsymmetrical boundary condition is applied, the desired longitudinal-bending coupling mode can be generated by a sine signal, which finally produces oblique elliptical movement on the end tip of the transducer. The design and analysis work is accomplished by finite elements method (FEM), and verified by a scanning laser Doppler vibrometer after the fabrication of a prototype. The proposed standing wave linear piezoelectric actuator achieves maximum no-load speed and thrust force of about 891.3mm/s and 39.2N under voltage of 400VP-P and working frequency of 29.4kHz.