Research On Position And Attitude Control System Of The Five Degrees-of-Freedom Air Bearing Spacecraft Simulator

Along with the development of the aerospace technology, the spacecrafts are expected to have higher attitude pointing accuracy and greater trajectory ability, and are expected to be more intelligent and agile while also being multifunctional. The application of advanced technologies not only ensure that the on-orbit-servicing spacecraft can finish the tasks, but also make the launching and controlling of a spacecraft to be a high-cost, high-risk venture. An effective way of reducing risk is that every parts of the system must be verified in the ground-base test-beds. The five degrees-of-freedom air bearing spacecraft simulator can create a micro-gravity and low-friction dynamic environment and simulate the motion of orbit and attitude. It can access directly circuit by hardware and software accomplishing the verification testing on the ground.This paper introduced the structure of the 5-DOF air bearing spacecraft simulator and work principle and component of every units. The precise model of the air bearing simulator was established in the Pro/ENGINEER environment.Accomplish the virtual centroid adjustment which can provide the basis for the actual centroid adjustment. Analysis the quality attribute of the simulator and calculate the inertia matrix which is the key parameter of attitude control system. Derive the math model of position and attitude of the simulator in which the actuators are air propulsion device and reaction wheel using equations of rigid body kinematics and dynamics. Analysis the disturbing forces and torques.Derive the controlling equations of the simulator's position and attitude on the base of the math model which describe the dynamics of position and attitude. Design different controllers for the two kinds of actuators respectively based on the different control strategies Sliding Mode Variable Structure Control and PID.Verify Sliding Mode Variable Structure Control strategy using the 5-DOF air bearing simulator based on air propulsion. The results show that the 5-DOF air bearing simulator can be controlled accurately and effectively.