Design And Experimental Research Of A Stick-slip Linear Piezoelectric Actuator With Active Locking Mechanism

Piezoelectric actuators have attracted the attention of researchers at home and abroad in the fields of aerospace,chip manufacturing and precision machining due to their high resolution,fast response and anti-electromagnetic interference.The ever-increasing positioning accuracy,load capacity and output speed,as well as smaller size structures,further expand the application scenarios of piezoelectric actuators.However,the retraction phenomenon of piezoelectric drive technology limits the performance improvement.How to improve the efficiency of the piezoelectric actuator and suppress the backward motion has become a problem that needs to be further solved.According to the basic theory of piezoelectric drive technology,various types of piezoelectric driven precision positioning devices are analyzed,and a stick-slip linear piezoelectric actuator with active locking mechanism is designed for the retraction phenomenon of piezoelectric actuators.Based on the stick-slip piezoelectric actuator,a set of locking mechanism is adopted to realize the active locking function of the slider.When the slider has backward motion,the locking mechanism exerts friction force opposite to the slider to restrain the backward motion.Based on the research of the backward motion of piezoelectric actuator,a prototype of piezoelectric actuator is developed,which consists of a base,a adjusting platform,a slider,a fixed substrate,a driving mechanism and a locking mechanism.The structure of piezoelectric actuator is optimized by finite element method and flexibility matrix.In addition,a dynamic model is constructed and the output characteristics of the piezoelectric actuator are simulated,which provides a reference for subsequent experiments.In order to verify the effect of suppressing the backward motion of the prototype,the output characteristics of the prototype are further explored.A test platform is set up to carry out single-stator control test and prototype test respectively.The experimental results of displacement,frequency and load of piezoelectric actuator are obtained.The experimental results show that the piezoelectric actuator can effectively suppress the backward motion.Moreover,the output speed and load capacity rate of the device have also been improved to a certain extent.When the input voltage is 100 V and the input frequency is 10 Hz,the output speed of the piezoelectric actuator is 43.5 μm/s,and the load capacity is 160 g.The maximum output speed can reach 2262 μm/s.Under the same conditions,when the driving mechanism works alone,the regression rate is 58%.When the piezoelectric actuator is working,the fallback rate is 0%,and the retraction phenomenon is obviously inhibited.In this thesis,a stick-slip linear piezoelectric actuator with active locking mechanism is designed to suppress the backward motion.The retraction phenomenon is effectively inhibited by the friction of the locking mechanism on the slider.It has some reference value to improve the output efficiency and output speed of piezoelectric actuator,and has some promoting significance to the research of piezoelectric precise positioning.