Research On The T-type Linear Piezoelectric Actuator With The Drive And Control System

Compared to traditional electromagnetic motor,linear piezoelectric actuator owns features of compact structure,linear motion without gear reducer and traction,fast response,and no external ma gnetic field interference etc.Research on piezoelectric actuators mainly focused on the new motor configuration,control strategy and application technology.Because the motor's control strategy directly affects motor's characters,research on its motion control strategy is particularly important.The purpose of this article is to achieve rapid and accurate position ing by build ing the mathematical model of piezoelectric actuator,designin g the general drive control circuit and looking for proper control strategy.This paper has designed and produced the T-type linear piezoelectric actuator and its motion platform.Accordin g to the actuator and produced experimental platform,the corresponding driv in g system has been built.The mathematical model of the controlled target is important to the control sy stem.The actuator's mathematical model can be divided into free vibration model of the stator,and the contact friction model between the stator and mover.Before considering the friction of the stator,according to the theory of Greenwood-Williamson,the contact friction mode l was set up.On the other hand,the electrical parameters of equivalent circuit was measured by untilizin g the Impedance Analyzer.The proposed friction model were initially verified by comparin g with the circuit equivalent model.The proposed model was used as a reference mathematical model for the control theory of the fourth chapter.Finally,the roughness and preloading experiments of the friction model was set up to verify the theory mathematical model.The motor drivin g system was designed and produ ced.It consists of main control unit and power amplif ier unit.The main control unit circuits main ly contains DSP and FPGA minimum system module,digital to analog conversion module and feedback module.DSP controller and FPGA DDS generator were integrated in a printed circuit board.The power supply of the PCB is 5 V.Power amplif ier unit was used to increase the output power and raise the output voltage level.It contains the power amplifier and high frequency transformer.This PCB was supplied by a 12 V source.Drivin g signal generator was programmed by Ver ilo gHDL in FPGA.The drivin g control algorithm and serial port communication was programmed by C programmin g language in DSP.The min imu m resolution of theoretical output voltage amplitude,frequency and phase were 1.17 V,2.24 Hz and 0.022°,respectively.The experimental platform has been tested to demonstrate that the output voltage waveform meets the system requirements.Based on the mathematical model of piezoelectric actuator in the second chapter and the drive control system of experimental platform in the third chapter,the last chapter was used to test and analyze the mechanical properties of the motor under various control algorithms by untilizin g the experimental platform.The motor speed trackin g control under the step and sinusoidal reference signals was realized by usin g the fixed gain PID control strategy.But,the problem of the low speed dead zone was found in the experiment.In order to solve the problem of dead zone,the improvement of control strategy was proposed by usin g dead zone compensation method.The validness of modif ied control strategy was verified by experiments.Furthermore,the variable gain PID control strategy based on fuzzy control was applied to improve the motor speed steady and dynamic characteristic.The experimental speed error was within ±2?m/ms.Finally,by tracking various reference position curves,the double closed loop control of the piezoelectric actuator drivn g control system was realized.Experiments results showed that the system could achieve 5?m minimum position error.