Research On The Torque Equilibrium Attitude And Attitude Controller Design Of Space Station

Representing the most complicated, advanced and integrated level of astronautical technology, Space Station has more important applications than other spacecrafts. The attitude control system is a fundamental component of the Space Station. It is playing an important role in the higher requirements of Space Station's pointing accuracy and its attitude stability. Momentum Management is aimed to monitor the momentum of CMG and keep it from saturation. Space Station can save its energy with the help of momentum management. The attitude control and momentum management control law have been studied in this thesis. The main contents are as follows:First, the kinetics model of Space Station is founded in this part. The attitude of Space Station is depicted in the form of Euler angle. In the assumption that the Space Station is a rigid body, kinetics model of rigid Space Station. Then, the vibration equation of beam appendage is derived by using lumped-mass method and the attitude dynamic model for flexible Space Station is obtained.Afterwards, the torque equilibrium attitude of Space Station is discussed. In this part, the models of aerodynamic torque, gravity gradient torque and gyroscopic torque are founded. Based on these models, an iterative algorithm which is used to calculate the torque equilibrium attitude is developed. Furthermore, the concept of the stability of torque equilibrium attitude and its judging methods are given. Then, two important factors, atmospheric density and the product of inertia, which are determinant to the torque equilibrium attitude, are discussed.The final part of this thesis is the design of the attitude control and momentum management controller. The kinetics model of the Space Station is linearized about the earth-oriented attitude. Based on the linearized equation and the momentum control equation of CMG, the state space equation of the attitude control and momentum management is obtained. In order to achieve the control purposes, state feedback controller is employed. By using the pole placement method, the state feedback controller is applied in both the pitch axis and roll/jaw axes. The flexible attitude dynamic model of Space Station is considered in the controller design procedures. The simulation results show that this controller can maintain the attitude of Space Station as well as keep momentum from saturation when disturbance exits.