Design Of Three-Axis Stable Attitude Control System Of Microsatellite

Microsatellite, a kind of modern small satellite, has advantages of light weight, small size, low cost and so on. It plays a more and more important role in various space missions. The attitude control system is the precondition of fulfilling all kinds of tasks, is the key technology and emphasis of study. In this paper, the attitude system of certain microsatellite is studied. Firstly, the mathematical model is built. After analyzing the parameter uncertainty and space environmental disturbances, attitude dynamics model of microsatellite are obtained accordingly, then the model is linearized. In follow, the H_∞ control theory, arithmetic and applications in microsatellite attitude control are described detailed. A robust H_∞ state-feedback controller of microsatellite attitude is designed. In order to decrease calculation greatly, the LMI method is adopted to solve the H_∞ controller. The simulation results indicate that the controller can improve robust performance and superior disturbance attenuation capability of the system. The H_∞ control improves the robust performance at a cost of damaging other performance. So a H₂ /H∞ state-feedback controller is designed. The controller has advantages of H_∞ controller and H₂ controller, not only can reject the influence of the internal uncertainty of moment-of-inertia variation and space environmental disturbances, but also can improve system dynamic performance. Lastly, three-axis stable attitude control system of certain microsatellite is designed. First of all, the scheme of attitude stable control system is put forward, then attitude sensors, attitude determination arithmetic and implement devices are introduced. Lastly, reaction wheel system is studied and simulated. The simulation results indicate the scheme of three-axis stable attitude control system can realize attitude stabilization of microsatellite.