Disturbance Suppression Technology And Experimental Research Of Airborne Two-axis Turntable Based On Adrc

This subject originated from a cooperative project.The project required the development of an airborne optoelectronic platform for a small laser weapon system.Among the various indicators of the optoelectronic platform,the tracking accuracy of the boresight is the most important one.Stable tracking accuracy of the boresight is conducive to the camera’s tracking of the target and at the same time conducive to the laser focus.However,during the flight of an aircraft,the airborne optoelectronic platform will be subjected to many kinds of disturbances,including the high frequency vibration of the aircraft engine,the attitude change of the aircraft,the wind load moment,the occasional impact and the disturbance from the mechanical structure and the electrical structure.The above-mentioned disturbances will cause the visual axis to vibrate or even deviate from the target.Therefore,how to deal with these disturbances and improve the anti-disturbance ability of the optoelectronic platform is the key to improving the tracking accuracy of the visual axis and is also the research goal of this subject.The disturbances are divided into two parts,the external and internal disturbances.Among the external disturbances,the influence of aircraft attitude changes is the most significant.After the dynamics modeling of the photoelectric platform,the coupling disturbance of the photoelectric platform’s shaft caused by the attitude change of the aircraft can be expressed as the disturbance torque on the two shafts.This paper makes a qualitative and quantitative analysis of the influence of this kind of disturbance torque on the servo system,which is convenient for the simulation when designing the control system later.This paper designed nonlinear and linear active disturbance rejection controllers,and compared the two controllers by simulation.In the case of step response,sine tracking,anti-sudden disturbance and anti-continuous coupling torque disturbance,the nonlinear active disturbance rejection control has shown superior performance.It has low delay,good dynamic performance,high steady-state accuracy,strong anti-noise ability and strong robustness.At the same time,it has low requirements for modeling accuracy of controlled objects.It is the best choice for anti-disturbance control of the airborne optoelectronic platform of this subject.The internal disturbance of the photoelectric platform is mainly the friction torque disturbance including bearing friction,slip ring friction and seal structure friction.In this paper,Lugre friction force model is used to model the friction force,and genetic algorithm is used to identify the friction force model parameters.The parameters obtained by the identification are used to compensate the nonlinear active disturbance rejection controller,and part of the known models are embedded in the expansion state observer.The simulation results show that the friction torque compensation improves the dynamic performance of the servo system.Finally,the experiment compared the dynamic performance,steady-state accuracy and anti-disturbance capability of traditional PID three-loop control,nonlinear active disturbance rejection control and active disturbance rejection control with friction torque compensation.The performance of active disturbance rejection control with friction torque compensation is better than the other two methods.