Analyse And Control Of Relative Motion For Formation Spacecrafts

In this paper, the relative motion and perturbation motion of formation satellites are analyzed in detail, and then the design of relative orbit and control law are researched into. Finally, the control of relative attitude is designed. The principal contents are summarized as follows:1) The mathematical descriptions of relative orbit kinematics and dynamics are studied. The effects of different orbit elements and position parameters on relative orbit of formation satellites are researched into. And the precise relative motion equations and simplified relative motion equations of formation satellites are deduced. Model errors of simplified equations are simulated. The simulation results show that model error of simplified kinematics equations is little.Based on perturbation theory of satellite, perturbation factors influencing relative orbit of formation satellites are analyzed. The relative perturbation expression of air drag and oblateness of the earth are deduced according to dynamics characteristics. And effects of these two perturbations on relative orbit are simulated. The simulation results show that, relative orbit incurs excursion under the perturbation factors, the effect of perturbation on each orientation is different, where effect on axis-y is the largest.2) The orbit design method of formation satellites are researched into in kinematics and dynamic respectively. And the two methods are analyzed in theory. Then, perturbation factors influencing whole orbit and relative orbit of formation satellites are analyzed and simulated. The result shows that perturbation effect on whole orbit of formation is larger than that on relative orbit. Finally, based on error equations of relative orbit kinematics, the relative orbit control law of formation satellites is designed. The simulation shows relative position error runs to errors' range quickly.3) The relative attitude is analyzed in kinematics and dynamics respectively. And the kinematics equations of attitude quaternion are studied in detail. And then the effects of earth gravity and air drag on relative attitude are researched into.4) Based on near-eigenaxis decomposition theorem of the relative attitude, the control law of relative attitude maneuver based on quaternion is designed and simulated. Firstly, kinematics and dynamics equations of formation satellites loaded reaction wheels are educed. And then, based on near-eigenaxis decomposition theorem and relative error quaternion equation, the control law of relative attitude is deduced. Then control system is confirmed to be steady-going using Lyapunov stabilization theorem. Finally, the control law of relative attitude maneuver is...