Design And Experimental Study Of A Stick-slip Piezoelectric Actuator

With the rapid development of advanced science and technology in biomedicine,integrated circuit,microelectronics engineering,aerospace and other fields,the demand for micro-nano positioning and driving is increasing.Stick-slip piezoelectric actuators have been widely used in micro-nano operating areas due to their high positioning accuracy,simple control system and simple structure,low power consumption,and large working range.The existing stick-slip piezoelectric actuators limit the further improvement of output performance due to the small step size,backward displacement and insufficient load capacity.With the purpose of improving the output performance of the stick-slip actuator,a stick-slip piezoelectric actuator with flexure hinge mechanism as the main stator structure was proposed.The coupling motion of the flexible mechanism is used to output displacement in both horizontal and axial directions at the same time.The static friction force is increased in the stick stage,and the dynamic friction force is reduced in the slip stage,so as to realize the adjustment of the friction force between the stator and the slider,increase the step displacement of the slider,and improve the output performance of the actuator.The main research contents are as follows:(1)The basic theoretical knowledge and application of piezoelectric driving technology were introduced.The working principle and force state of stick-slip piezoelectric actuator were analyzed in detail,the force and deformation of the selected right circular flexure hinge were analyzed.The flexure hinge mechanism and the overall structure model of the actuator were designed and the experimental prototype was also manufactured.(2)For the flexure hinge mechanism of stick-slip piezoelectric actuator,the characteristic frequency,strain and stress were analyzed by finite element software,and the maximum output displacements in horizontal and axial directions were determined,which verified that the designed flexure hinge mechanism can meet the requirements of frequency,displacement and stress.(3)The experimental platform was set up to carry out performance testing,and the output performance such as velocity characteristics,resolution,maximum step displacement,load capacity and driving foot displacement were studied.The test results show that when the locking force is 2 N and driving frequency is 370 Hz,the displacement resolution of the actuator is 0.028 μm at the minimum starting voltage of 6 V.Under the locking force of 4 N and the driving frequency of 550 Hz,the actuator achieves a maximum speed of 10.23 mm/s at a voltage of 100 V.Under the locking force of 4 N and the driving frequency of 550 Hz,the actuator has a maximum speed of 13.706 mm/s and a maximum step displacement of 24.92 μm at the voltage of 100 V,which can achieve stable linear motion in the range of 200 g horizontal load.The feasibility of friction self-regulation of flexure hinge mechanism is verified by the displacement test results of driving foot.(4)The dynamic model of stick-slip piezoelectric actuator was established,and the Lu Gre friction model suitable for stick-slip motion was selected to analyze the stepping motion.The motion displacement,the minimum step displacement and the motion displacement of the slider mass change were analyzed based on Simulink function.The error between simulation results and test results was compared to analyze the rationality of the dynamic model.In this paper,the stick-slip piezoelectric actuator was studied,and the rationality of the structural design was verified by finite element simulation.The experimental prototype can not only achieve a large step displacement and a large motion speed at a lower driving frequency,but also maintain a good displacement resolution,which is capable of the requirements of large stroke precision operation.