Research On Disturbance Observer And Fractional PID In Photoelectric Tracking System

The photoelectric tracking system is a comprehensive system widely used in reconnaissance,photoelectric countermeasures,countermeasures against aircraft targets,and accurate measurement.As the ship is in the process of using equipment,it will be affected by various factors such as waves and wind.As a result,the photoelectric equipment will perform the same actions as the ship,which greatly reduces the accuracy of capturing and tracking targets.By analyzing various factors that affect the tracking accuracy of photoelectric tracking equipment,this paper uses a two-level channel composite control method of coarse and fine channels.The coarse tracking channel uses fractional PID control and Disturbance Observer combined with robust control based on the control system using traditional PID control.The fine tracking system adopts the control system of the controlled object mainly based on the quick response mirror to eliminate the residuals of the coarse tracking control system.For the disturbance of tracking of the submarine sway,the Kalman filter is used to compensate the disturbance to the coarse tracking control system,which reduces the error caused by the rotation of the field of view to the aiming.First,by analyzing various disturbances to the photoelectric tracking system,starting from the coarse tracking channel and the fine tracking channel in the composite axis control method,the tracking models are established from the controlled objects of the two channels,and the effectiveness of the composite axis control is effectivly analyzed,and the principle is simple and verified.Secondly,the control method is improved from the model established by the controlled object in the coarse and fine tracking channels.In order to ensure that the control system is not affected by external interference and other factors that cause the tracking accuracy to decrease,it has sufficient stability and robustness.Starting from the coarse tracking channel,fractional PID control and interference observer are used to eliminate other interference factors such as model uncertainty,which enhances the performance of suppressing disturbances.Combined with the fine tracking channel,the integer-order PID is used to control the fast mirror,and the control results of the composite axis are numerically analyzed.Finally,for the ship sway that can be more accurately predicted,a feed-forward compensated boresight is designed.In this case,a prediction method based on Kalman filtering is used to reduce the impact of ship sway on the tracking accuracy of the system,and the prediction is established on the target motion model to estimate the disturbance and achieve the effect of compensation.