Evolution of one-stepping characteristics of a stick-slip piezoelectric actuator under various initial gaps

Abstract

To investigate the effects of initial gap on the one-stepping characteristics of stick-slip piezoelectric actuators, a stick-slip piezoelectric rotary actuator with changeable initial gap was designed and fabricated. Its output characteristics were tested under various initial gaps. Experimental results indicated that the initial gap indeed significantly affected the output characteristics in one driving cycle, especially at the final stage when the driving voltage was decreased quickly. Gradually increasing the initial gap, an interesting phenomenon was observed that the one-stepping characteristics in the final stage transformed from the sudden return (the so-called backward motion) to a critical status (nearly smooth motion), and finally to sudden jump. By analyzing the practical driving waveform as well as the additional deformation of the actuator, the evolution of one-stepping characteristics was rationalized. These findings and discussion are expected to enhance our fundamental understanding of the stick-slip principle and actuators. In addition, this study suggests a method to suppress the backward motion by simply changing the initial gap.