Miniaturization of a U-shape linear piezoelectric motor with double feet

• A U-shape linear piezoelectric motor with double driving feet is proposed and bonded-type structure to realize the miniaturization.
• Three orthogonal longitudinal vibrations are superimposed in the motor to produce elliptical movements on the two feet.
• Maximum speed and thrust force of 765 mm/s and 7.3 N are reached by a prototype with weight of 0.026 kg.
• The maximum power density of the prototype is 46.15 W/kg, which is about 6.4 times of a previous work.

A U-shape linear piezoelectric motor with double driving feet is proposed and tested. It adopts bonded-type structure to realize the miniaturization. Six pieces of PZT ceramic plates are bonded on a U-shape duralumin alloy base to form the motor. This structure makes it has simple fabrication and assemblage processes. The proposed motor produces elliptical movements on the two driving feet by the superimposing of longitudinal vibrations. The resonance frequencies of the two vibration modes are tuned to be close at about 54 kHz. Transient analysis is developed to illustrate the movements of the driving feet. The vibration characteristics of a prototype are measured by a scanning laser Doppler vibrometer. The no-load speed and the maximum output thrust force of the prototype are tested to be 765 mm/s and 7.3 N, respectively. The weight of the miniaturized U-shape piezoelectric motor is about 0.026 kg; its power density is about 6.4 times that of the previous one with bolt-clamped structure.