Design And Control Of Variable Stiffness Semi-active Vibration Controller Based On Piezoelectric Actuation

The insufficient stiffness of the robot will lead to vibration or even chatter under exterior excitation,which seriously affects the robotic drilling precision and cutting life.The technology of position and stiffness compensation has a better effect on the static error compensation caused by insufficient static stiffness,but the dynamic error compensation effect caused by the coupling vibration of the drilling system caused by the thin-wall workpiece vibration,drilling vibration and vibration drilling additional vibration is poor.Therefore,in the process of drilling,the vibration control effectively is crucial.In this paper,a semi-active vibration controller with variable stiffness based on piezoelectric actuation is proposed,a dynamic model of the semi-active vibration controller is established and the structure of the vibration controller is precisely designed according to the dynamic model on the basis of the analysis of active vibration controllers and passive vibration controllers at home and abroad.Finally,the variable stiffness control of the piezoelectric actuator is performed.The main research contents are as follows:1?A model of the passive vibration controller of the robotic drilling system is established,and the influence of the parameters of the vibration control system on the absolute displacement transfer rate of the end effector of the robot is analyzed.The optimal parameters of the vibration controller are obtained through the optimization algorithm,and analyzing the passive vibration controller's vibration control effect prepared for the propose of variable stiffness semi-active vibration controller.2.The variable stiffness semi-active vibration control is proposed on the basis of the passive vibration controller.The piezoelectric ceramic material is used as the driver to change the stiffness of the dynamic shock absorber.A variable stiffness semi-active vibration controller model based on piezoelectric actuation is established and analyzed.The relationship between the optimal stiffness of the dynamic vibration absorber and the external excitation is verified.The central difference method is used to verify that the vibration control effect is better than that of the passive vibration controller.3.Designed the overall structure of the variable stiffness semi-active vibration controller based on piezoelectric actuation,and carried out specific analysis and design of each part.The stress and strain analysis of the elastic elements in the vibration controller is performed.Finally,the influence of the size changes of the vibration controller parts on the vibration control effect of the vibration controller is analyzed to ensure the optimality of the designed structure.4.Established a mathematical model for the hysteresis of piezoelectric ceramic materials,the unknown parameters in the model is determined,and adopted feedforward compensation-PI feedback control to perform composite linearization control of piezoelectric actuators,and analyzed degree of linearization of the control method through simulation.Finally,a joint simulation experiment is designed for the variable stiffness semi-active vibration controller based on piezoelectric actuation proposed in this paper.The experiments verify the rationality of the structure of the vibration controller and the practicability of the control method.