Research On Robust Servo Control Method Of Photoelectric Stabilized Sighting Pod

Photoelectric stabilized sighting pod can isolate external interference and ensure that the visual axis of the optical load carried inside it always has a stable direction relative to the inertial space.As a kind of advanced equipment,it is widely used in the military and civilian fields to realize the tasks of reconnaissance,detection,tracking and attack on targets.Due to the complex working environment of the pod,it is often affected by various internal and external disturbances.These disturbances will affect the stability of the visual axis,and in severe cases,the optical load will not work properly.Therefore,it is very important to improve the ability of the pod to isolate disturbances.This paper takes the two-axis and two-frame photoelectric stabilized sighting pod as the research object,and aims to improve the anti-disturbance capability of the pod.The following research works are carried out:1)The system of photoelectric stabilized sighting pod is analyzed in detail,including system composition,frame structure characteristics,working mode,passive vibration isolation and active stabilization principle,as well as various disturbance factors.The mechanism of each component of the velocity loop is analyzed and modeled.The transfer function model of the pod is established through the sweep experiment and system identification method.2)The active disturbance rejection control and internal model control of the photoelectric stabilized sighting pod are studied.Internal model control has strong robustness,but it is a single-degree-of-freedom controller,the dynamic characteristics and robustness of the system need to be compromised when tuning parameters,and the separation design of system tracking performance and disturbance suppression capability cannot be achieved,and it can not effectively suppress interference such as modeling errors.In order to solve the above problems,the linear active disturbance rejection control(LADRC)and error-based linear active disturbance rejection control(Error-based LADRC)are deeply studied,by learning from its active disturbance rejection ideas,the Error-based LADRC is introduced into the internal model control structure,an internal model control method based on Error-based LADRC is proposed.In this control structure,the internal model controller is used to specify the expected output trajectory of the system,which determines the system’s tracking performance,and the Error-based LADRC controller is used to compensate the modeling errors,external disturbances and other disturbances,which determines the system’s anti-disturbance capability.A large number of comparative simulation studies are carried out based on the velocity loop model of the photoelectric stabilized sighting pod.The results show that the proposed method has good disturbance suppression ability and robustness,and can improve the performance of the photoelectric stabilized sighting pod system.3)Based on the laboratory’s two-axis and two-frame photoelectric stabilized sighting pod experimental platform,the PI control,internal model control,and internal model control based on Error-based LADRC are implemented for photoelectric stabilized sighting pod disturbance suppression and parameter perturbation robustness.The experimental results verify that the internal model control method based on Error-based LADRC can effectively improve the disturbance suppression capability of the pod system.