Adaptive Compensation For Disturbances Of Airborne Photoelectric Stabilized Platform

Airborne Photoelectric stabilized Platform acquire information by onboard multichannel optical instruments,simultaneously combined with wide-range mobility of aerial carrier,which makes itself a significant links in battle information acquisition in modern information warfare,and it has got widely used in regional wars in past decades.Centering on enhancing dynamic response performance and disturbance rejection ability of Airborne Photoelectric stabilized Platform,the thesis conducts studies on three following aspects.Firstly,specific to alleviate the overshoot problem caused by hysteresis characteristic of integral term,the modified PI controller is designed by introducing exponential fading factor to integral term to improve dynamic performance,and its general expression under Laplace transformation is deduced.The Bode diagram shows that the modified PI controller has the wider middle frequency bandwidth and the higher cross-over frequency,the lower closed-loop resonance peak and the wider closed-loop bandwidth.The step response curves show that the modified PI controller obviously alleviates overshoot and decreases setting time,which mean a significant improvement of dynamic response,besides,disturbance rejection ability is improved.Secondly,considering the fact of tiny accessibility and time variation of formulaic friction model,the friction's adaptive compensation method based on model reference adaptive control(MRAC)is studied,and compensation strategies are designed by using gradient method and Lyapunov stability theory respectively.According to simulation results,the origin control structure of MRAC is improved which generates a new structure that contains two feedback loops.Adaptive control law is designed based on proposed structure and its convergence is proved.The simulation examples show that the improved control structure has faster convergence speed and better compensation effect.Finally,to sufficient take advantage of spatial information of disturbance,iterative learning control strategy(ILC)with parameters updated in spatial domain is studied,on whose basis disturbance adaptive compensation law is designed.The P type learning law is given and its convergence is proved.The feasibility of the linear interpolation to transform sapling data between time domain and spatial domain is analyzed.Then,in view of the control delay of tracking loop,the PD type learning law,which adopts pre-given error information,is designed,and the convergence is proved.Parts of study results of chapter 3 and chapter 4 is verified by experiment.