Cooperative Formation Control Of Airbearing Simulators And 3D Realtime Simulation

With the rapid development for the astronautics and aerospace technology,more and more attention are paid to the whole physical simulation system of air-bearing testbed(WPSS-ABT)due to its advantages such as lower cost,longer duration and less disturbance.The WPSS-ABT of 3-Degree satellites can provide a intact simulation for microgravity environments,thus offering a vital assistance for research of various space tasks.Since multiple-satellite cooperation is capable of some complicated tasks that can not be done by single satellite,researches on WPSS-ABT have been launched by institutes from both home and abroad.In this thesis,a virtual WPSS-ABT based on NCSLab is set up.extending the functionality of NCSLab,and a leader-follower algorithm for flight algorithm is proposed,which was both implemented on the virtual WPSS-ABT and experimented on a practical WPSS-ABT,illustrating the effectiveness the proposed algorithm.Firstly,the structure and working mode for the satellite simulator are surveyed,the motion description for satellite simulator in both the body-coordinate and inertiacoordinate are reviewed based on rigid-body mechanics,and some preliminaries for flight formation are provided.Secondly,the kinematics and dynamics for the satellite simulator are derived,the state space description for the dynamics of the simulator is established.Based on the mathematical model of the satellite simulator,the trajectory tracking algorithm is designed for the satellite simulator by partitioning the model into the speed control unit and position control unit.Moreover,the stability analysis of the closed-loop system is performed by the comparison lemma and Lyapunov stability theorems.Furthermore,the flight formation algorithm is designed using the improved leader-follower approach,with the tracking reference of each satellite designated.Also,the S-function for flight formation algorithm is coded.Thirdly,the virtual WPSS-ABT is set up,the 3D model of the satellite simulator is established based on the extension functionality of the experiment platform,by which the 3D annotation is designed.With the virtual WPSS-ABT,not only the parametric change can be visualized,but also the real-time running of the virtual test rigs can be observed,simplifying the experiment preparation procedure,lowering the experiment time and nitrogen consumption.Finally,both simulations on virtual WPSS-ABT and experiments on practical WPSS-ABT for both single satellite and triple satellites are conducted,respectively.Simulations show that the formation system can run smoothly under permitted performance requirements,and the experiments show that the proposed algorithm,though with some practical constraints,still provides robustness against some external disturbance.