Design And Experimental Research Of Piezoelectric Stick-Slip Actuator Based On Flexure Amplification Mechanism

Piezoelectric stick-slip actuators are widely used in advanced manufacturing equipment because of the advantages of simple structure,theoretically infinite travel,millisecond level fast response,and no electromagnetic interference.However,due to the limited deformation length of the piezoelectric elements,the output velocity and the comprehensive output performance of the actuator at low frequencies are seriously affected,which hinders its further expansion and application.In order to solve the above problems,based on the topology optimization method and the dual-mode orthogonal design idea,the topology optimization flexure hinge type actuator and the orthogonal rhombic compliant mechanism type actuator for the overall design of the piezoelectric stick-slip actuator based on the flexure amplification mechanism are proposed in this paper,which realizes the linear and rotary movement and effectively improves the stepping efficiency of the piezoelectric stick-slip actuator,and comprehensively regulates the static and dynamic friction forces during the stick-slip stage to improve the comprehensive output performance of actuator.Firstly,the basic theory of piezoelectric actuator is elaborated in this article,including the introduction to piezoelectric forward and inverse effects,piezoelectric materials,and piezoelectric stacks.Subsequently,the overall design approach for flexure hinge mechanism based on the Solid Isotropic Material with Penalization(SIMP)was revealed,and the design domain,objective function,and constraint function were determined.The mathematical model of topology optimization is established and the sensitivities of the objective function and constraint function are calculated.Finally,the optimization result is obtained by using the Moving Asymptotes Method(MMA).the boundary extraction and design of the topology optimization result are carried out,the overall structure of the topology optimization flexure hinge piezoelectric actuator is determined,and the operating principle of the actuator is analyzed.Then,the finite element simulation analysis of the stator is carried out,including static,stress and modal analysis.Secondly,the mechanical analysis of orthogonal rhombic compliant mechanism is carried out to clarify the deformation movement process of the mechanism,and the expression of the relationship between the output displacement and the mechanism characteristics is obtained,which provides theoretical guidance for the subsequent determination of the key dimension parameters of the mechanism;In addition,the overall structural design of the orthogonal rhombic compliant mechanism type actuator is carried out,and the dual-mode operation principle is clarified.Based on the finite element analysis method,the final size of the orthogonal rhombic mechanism is determined by comprehensively considering the mechanism amplification effect and stiffness factors,and the feasibility of the dual-mode operation method and the orthogonal design idea is verified through the simulation results.Finally,the prototypes of the topology optimization flexure hinge type and the orthogonal rhombic compliant mechanism type piezoelectric stick-slip actuators are developed,and the corresponding experimental test systems are equipped and tested.The experimental results show that under locking force of 1 N,the topology optimization flexure hinge type actuator achieves a velocity of 15.25 mm/s under the signal excitation frequency of 650 Hz,has a load capacity better than 330 g under 3 N locking force,and the motion resolution can reach 96 nm.In addition,under the locking torque of 20 N mm,the orthogonal rhombic compliant mechanism type actuator can achieve the rotation angular velocity of 3412.5 mrad/s and 3319.5 mrad/s respectively counterclockwise and clockwise in the cooperative operating mode,and the motion resolution can reach 7.42 μrad and 8.76μrad respectively in precision driving mode.It has high operating velocity and accuracy,and ensures consistency in bidirectional operation.The experimental results and performance comparison indicate that both types of flexure amplification mechanism based piezoelectric stick-slip actuators developed have good output performance.