Research On Attitude Control Technology Of Three Axis Stabilized Zero-momentum Wheels Satellite

Satellite attitude control system is the guarantee of the mission completion. Control accuracy and reliability are two vital indexes to measure the satellite attitude control system.Among all the actuators in the satellite engineering,the zero momentum wheels are simple,reliable and have high precision, so we choose it as the actuator of attitude control system to study the attitude control technology of the satellite.Considering the features of three axes stable zero momentum wheels satellite control system, this paper designs the three control methods, including PID algorithm, fuzzy PID algorithm and sliding mode variable structure algorithm, meanwhile, numerical simulation results are presented to confirm the validity and superiority of the proposed method, the main works in the paper are presented as follows :First of all, the exordium. The paper introduces the background, purpose and significance of the research, the main control algorithms of the satellite control system and the development status at home and abroad are summarized,meanwhile, the main content of this paper is described in detail.Secondly, attitude description and mathematical model. The transformation relation between the space coordinate system and the space coordinate system is established.According to the description methods of the Euler Angle and quaternion,the kinematics model of the satellite is established. According to the momentum theorem of rigid body and related knowledge, the dynamic model of satellite is deduced. The mathematical model of the space environment disturbance torque is derived. The actuators of the satellite is introduced.Based on the above knowledge, the simulink model of the satellite is established.Finally, three control algorithms are analyzed and designed:(1) Point to the above mathematical models, the three-axis satellite attitude system is decoupled into SISO system. The PID controller of the satellite is designed, and the parameters of PID are obtained by the pole assignment method. The control performance of the PID controller is not ideal when the parameter perturbation are taken in different percentage.(2) With the continuous development of the satellite, the satellite system becomes more and more complex, the classical PID control has a certain degree of difficulty in the adjustment parameters, and can't adapt to the satellite system to adjust. In order to solve the above problems, the theory of intelligent control and the traditional PID control are combined together,which is the inevitable trend of the new control algorithm. In this paper,we select a kind of fuzzy control in intelligent control system combined with the traditional PID control,a fuzzy PID attitude control algorithm is deduced. the simulation illustrates the better adaptive performance of the proposed control method.(3) In the process of satellite operation,the sliding mode variable structure control is realized. The quasi sliding mode method is used to weaken the chattering. Under the different percentage of parameter perturbation, by comparing the simulation curves of PID control and sliding mode variable structure control, sliding mode variable structure control has strong robustness against both internal parameter perturbation of the satellite and external disturbance.