Research On The Method Of Flexible Satellite Attitude Rapid Maneuver And Pointing Tracking Control

For the requirement that low orbit imaging satellite tracking the moving target,this thesis does some research on satellite rapid maneuver and pointing trackingcontrol. The main contents as follows:Firstly, the actuator SGCMG which is suitable for the satellite with the abilityof rapidly maneuvering is researched, the problem that SGCMG has the minimumgimbal speed is solved. Two methods are designed to avoid the gimbal dead zone,one is adding null-motions, and the other is adding a set of flywheel to form thehybrid actuator system.For the characteristic of pointing tracking which required some axis of thesatellite body pointing to the target point, the target coordinate system is establishedwith the shortest path, and the new attitude parameters is presented which suit forthe pointing tracking control system. These parameters can provide a simple andunified kinematic model, which is the foundation of the design of control system.The feed forward expression is deduced on math, and he influence on attitudecreated by the flexible appendage vibration is analyzed.After building the model of satellite, the cascade saturation PD controller isdesigned for the problem that the initial Euler axis and the initial angular velocity isnot collinear. The general method of choose the parameters of the cascade saturationPD controller is given. The cascade saturation sliding mode controller is designedfor the problem of the bandwidth of cascade saturation PD cannot be too big, and itsstability is provedFor the influence of discrete and delay on the control system, the typicalsecond-order system with PD controller is analyzed using the method of ztranslation, and the general formula for designing the controller bandwidth is given.The restricted relationship of the controller parameters is given by simulations forthe discrete control system with a step delay. The predictive controller is improvedfor the quickly changed system, and the single axis predictive controller is designed,which is extended to the three axes attitude control system.The flexible appendage vibration is not suppressed directly in the process of controller design both of the continuous controllers and discrete controllersdesigned formerly. For this characteristic, the vibration suppression method of inputshaping is improved, which is extended to the system with the couple of severalflexible appendages，the system of PD controller of closed-loop, and the system ofno zero initial states. At last, the PD controller tracking the shaped expectationstates is designed. The controller does not limit the torque amplitude directly, butrestricted the output torque by planning the target path. Shaping on the target pathcan theoretically suppress the vibration totally in the condition of zero initialangular velocity.