Research On Unbalance Disturbance Control Method Of Magnetic Beraing Rotot System Aboard Satellite

With the development of science and technology,the process of human exploration of space has accelerated.In order to meet the needs of different missions,spacecraft often carry rotating loads.However,due to material,processing and assembly errors,the rotating loads have unbalance.Especially for rotating loads with large inertia,the unbalance will cause interference force and interference moment,which will adversely affect the normal operation of the spacecraft,and even lead to the failure of the spacecraft mission.Compared with mechanical bearings,magnetic bearings make the rotor suspend by magnetic force,which have unique advantages and broad application prospects in spacecraft.This paper takes the magnetic suspension rotor aboard satellite as research object,considers the static and dynamic unbalance of the rotor,and design the control strategy of the rotor and satellite platform.The specific research content is as follows:Firstly,the dynamic modeling problem of magnetic suspension rotor aboard satellite is studied.Based on the rigid body assumption and considering the static and dynamic unbalance of the rotor,a magnetic suspension rotor dynamic model is established.Then considering the motion of satellite platform and based on the quasi-coordinate Lagrange equation,a complete dynamic model of satellite system is established.Analyzing the two dynamic models,combined with the decentralized PD control,it is clear that the unbalance of rotor will affect the motion of the rotor and the satellite platform.Then,the unbalance disturbance control problem of magnetic suspension rotor fixed on the base is studied.Based on the theory of auto disturbance rejection control,the rotor unbalance is regarded as a part of the total disturbance of the system.The extended state observer is designed to estimate the system state including the total disturbance of the system,and the estimated value of the total disturbance of the observer is introduced into the controller design.In the process,the disturbance is compensated,and the influence of the rotor unbalance is theoretically eliminated.Based on this,the linear auto disturbance rejection controller and the nonlinear auto disturbance rejection controller are designed respectively,and the effectiveness of the controllers is verified by mathematical simulation.Finally,the control problem of the satellite platform with magnetic suspension rotor aboard satellite is studied.Based on the established magnetic suspension rotor aboard satellite dynamics model,the rotor and the satellite platform are coupled,and the satellite platform is affected by the unbalanced disturbance torque of the rotor,and considering the external disturbance,PD controller based on interference observer,PD controller based on improved interference observer,exponential reaching law sliding mode controller and adaptive terminal sliding mode finite-time controller are designed respectively for satellite platforms.Considering the external disturbance,the rotor adopts the nonlinear auto disturbance rejection controller,and the four controllers designed for the satellite platform are simulated and verified.The results show that the proposed control methods can achieve high-precision control of the satellite platform and the unbalanced disturbance control of the magnetic suspension rotor aboard satellite.