Research On Sliding Mode Variable Structure Control For Gyro Stabilized Platform

The gyro stabilized platform is a device that uses a gyroscope as the feedback element to realize the effect of the isolation carrier base on the load disturbance,and is mainly used to track the target accurately.Its development is of great significance to China's national defense and civil undertakings.Especially in recent years,due to changes in the environment applicable to gyro-stabilized platforms,the requirements for various performance indicators need to be further improved.In particular,the requirements on the system's rapid response,maneuverability,and performance requirements such as capture,tracking,and aiming during travel are more stringent.Therefore,there is an urgent need for a control algorithm that can achieve high-precision,fast response,and solve the problem of uncertain systems to improve the system's performance indicators.At present,the control technology of the gyro stabilization platform mostly adopts PID or its improved control algorithm,but the application of the gyro stabilization platform leads to PID or its improved control algorithm cannot effectively realize the dynamic and static performance of the system.Therefore,in this paper,a sliding mode variable structure control method is proposed to solve the problem of large tracking error in PID control.Sliding mode variable structure can achieve complete self-adaptability to the system's external disturbance,perturbation,and uncertainty of parameter changes.This is very important for high-precision,complex application of gyro-stabilized platforms.The simulation results show that compared with traditional PID control,sliding mode variable structure control can reduce the steady-state error and achieve input tracking.The maximum error of position tracking is 0.007 rad,and the maximum value of the velocity tracking error is 0.2 rad.At 0.25 s,the velocity tracking error is close to a certain neighborhood of zero,and the disturbance isolation is 0.25%.From the speed tracking curve and the switching function curve,it can be seen that the system tracking has the jitter problem,which will not be conducive to the stability of the actual system,so it is necessary to further improve the controller according to the jitter problem in the variable structure control.In this paper,neural network is used to improve the sliding mode variable structure.The adaptive approximation of unknown part of the model is realized by using the approximation property of neural network,so as to improve the effect of handover.The simulation control experiments on the gyro stabilized platform show that the neural network is used to improve the sliding mode variable structure,which can effectively reduce the jitter of the sliding mode variable structure control,and the isolation degree of the system to the disturbance is 0.2%.Compared with the simple sliding mode variable structure control,the isolation degree is increased by 25%,which has higher practical value.