Research And Design Of Servo Control System For Photoelectric Stabilized Platform

The photoelectric stabilized platform is a servo platform mounted on the moving carrier,which can isolate the disturbance of the carrier,realize the accurate tracking of the moving target through the image detection equipment,and play an important role in mapping,detection,positioning and tracking.In order to improve the stability accuracy and tracking accuracy of the system,this paper takes the two-axis and two-frame photoelectric stabilized platform as the research object,and studies the speed stabilized loop and position tracking loop in depth.The corresponding control strategies are designed according to the existing problems,and the hardware circuit and software implementation of the servo control system are designed.The main research contents are as follows:First of all,under the disturbance of nonlinearity,time-varying and uncertainty,the traditional PID control method has low control efficiency and unsatisfactory performance index.The soft variable structure control(SVSC)as a modern control theory provides an effective method to approach the optimal control performance.By analyzing the two control methods of SVSC,aiming at the problem that the control parameters of the SVSC with variable saturation and dynamic SVSC are more complex,the dynamic SVSC method is simplified and integrated with PI control.A simplified dynamic soft variable structure PI(SDSVSPI)control method is designed.The algorithm is discretized so that for the discrete control program can be written.Secondly,the paper analyzes the composition and working principle of the servo system of the photoelectric stabilized platform,establishes the mathematical model of the controlled object of the servo system,constructs the speed stabilized loop of the platform,and constructs the loop in MATLAB/Simulink.In order to improve the dynamic performance of the speed loop,the PI controller,the SVSC with variable saturation and the SDSVSPI controller by particle swarm optimization(PSO)algorithm are used.The simulation results show that the SDSVSPI controller is superior to the other two controllers in terms of rise time and anti-interference ability,and has higher dynamic performance.Aiming at the external disturbance to the speed stabilized loop,a disturbance compensation control based on disturbance observer(DOB)is introduced.The simulation results show that the DOB-SDSVSPI controller has stronger effect of disturbance isolation and higher stability accuracy.Aiming at the problem that the miss distance of position tracking loop has uncertain time-delay,a delay compensation control based on the extended Kalman filter(EKF)algorithm is adopted.The simulation results show that the method can compensate the miss distance delay well.Finally,the hardware circuit of the servo control system of the photoelectric stabilized platform is built,and the programs based on the signal processing of the angular position encoder,the signal processing of the rate gyro and control algorithm are compiled.The experiments of velocity disturbance and position tracking are carried out on photoelectric stabilized platform,which verify the effectiveness of the control strategy and achieve high stability accuracy and tracking accuracy.