Design And Experiment Of Piezoelectric Stick-Slip Actuator Based On Double-excitation Composite Driving Method

Piezoelectric actuator has gradually become one of the mainstream technologies in high-precision fields such as MEMS,semiconductor manufacturing,optical instrument micro-operation and medical science because of its advantages of high control accuracy,fast response speed,anti-electromagnetic interference and simple transmission mechanism.At present,the application of piezoelectric drive technology in products is mainly based on ultrasonic technology and stick-slip technology.Among them,the piezoelectric actuator using stick-slip technology has become a key research object in the field of drive at home and abroad due to its simple structure,low manufacturing cost,and long-stroke cross-scale drive.However,the current stick-slip actuator has a displacement back phenomenon due to the existence of dynamic friction resistance,which leads to a series of problems such as low output efficiency,slow speed and small driving force.In this paper,the design method of piezoelectric stick-slip actuator based on double-excitation composite drive is proposed.The piezoelectric double-excitation composite drive combines the two excitation methods of stick-slip and ultrasonic.In the “slip stage” of stick-slip motion,the ultrasonic vibration antifriction effect is generated by the excitation of the piezoelectric patches to reduce the dynamic friction resistance.The prototypes of friction rod type and flexure hinge type piezoelectric double-excitation composite actuator are developed and a series of systematic experiments are carried out.The research results of this subject can further promote the development of piezoelectric actuators in high-precision fields such as optical instruments and precision manufacturing.Firstly,based on the investigation and analysis of the research status of piezoelectric actuators at home and abroad,this paper clarifies the bottleneck problems existing in the development of piezoelectric actuators.At the same time,the basic theory of piezoelectric effect,piezoelectric material,piezoelectric stack structure and the configuration of flexure hinge are deeply analyzed,and the displacement of the straight circular flexure hinge in all directions is calculated.The dynamic model of the actuator is established,and the mechanism of ultrasonic vibration friction reduction is analyzed.Secondly,the design method of piezoelectric stick-slip actuator based on doubleexcitation composite driving is proposed.The friction rod piezoelectric double-excitation composite actuator and the flexure hinge piezoelectric double excitation composite actuator are designed respectively.Then,the specific structures of the two piezoelectric stick-slip actuators are described in detail.According to the law of the electrical signal,the working state of the mover and the stator is analyzed to determine the feasibility of the working principle.The excitation frequency of the ultrasonic electrical signal is preliminarily determined by modal simulation analysis.The static simulation analysis can verify the amplification effect of the flexure hinge mechanism on the elongation of the piezoelectric stack.Finally,a prototype of a friction rod type and a flexure hinge type piezoelectric dual excitation composite actuator was developed,and a prototype test system was built.The impedance characteristics of the prototype were tested to analyze the resonance frequency of the prototype,and then the excitation frequency of the piezoelectric plate was adjusted.Then,the basic performance of the piezoelectric dual-excitation composite actuator was tested.The experimental results show that compared with the traditional driving method,the positive/reverse speed of the friction rod piezoelectric dual-excitation composite actuator is increased by 30% and 26.7% respectively under the dual-excitation composite driving method.The clockwise/counterclockwise speed of the flexure hinge piezoelectric dualexcitation composite actuator is increased by 17% and 9% respectively under the dualexcitation composite driving method.