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

•A novel standing wave linear piezoelectric actuator is proposed.•The longitudinal-bending coupling mode of a beam is proposed and discussed.•A longitudinal-bending hybrid vibration is generated by one group of PZT elements.•Oblique elliptical movement is produced on the end tip of a sandwich transducer.•The prototype achieves maximum no-load speed and force of 891.3 mm/s and 39.2 N.

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 1 st 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 891.3 mm/s and 39.2 N under voltage of 400 VP-P and working frequency of 29.4 kHz.