Research On Attitude Control Schemeof The Multi-Body Attached By Non-cooperative Spacecraft

In application and space confrontation, non-cooperative targets are involved in many cases. Since the quality of the non-cooperative spacecraft and the specific form of motion are unknown, the attitude control system will be faced with great challenges. In order to solve the problem of interference caused by non-cooperative attachment, the attitude control system of the new combination is mainly studied in this paper. As the inertia parameters of the new combination are unknown, two methods are proposed to solve this problem. Respectively, one method is based on inertia parameters in-orbit identification and the other one is based on constructing inertia estimation. Thus, the dynamic model of the new combination can be constructed, and the attitude control schemes of the new combination are studied.Firstly, a theme of inertia parameters in-orbit identification based on �zero-momentum system� is proposed. The inertia parameters can be identified in orbit through series of output data from the momentum wheel and three axis rate gyro. Then a simulation platform for the non-cooperative attachment can be built. The traditional PD control model is tested on the simulation platform under non-cooperative attachment, and some shortages are found by analyzing the simulation results. Under this background, a variable structure control law is designed. The control scheme can be sensitive to the variation of the inertia parameters of the new combination. And it is proved quite effective through the simulation under different cases.Secondly, in order to overcome the drawbacks of the variable structure scheme and PD control scheme, nonlinear adaptive control scheme based on inertia estimation of the new combined system is designed. Apart from better attitude control, the inertia parameters can also be estimated by the control scheme.And it is proved better in the adaptive control of non-cooperative attachment for the new combination through the simulation under different cases.Finally, based on the simulation by three axis air bearing table, hardware-in-the-loop simulation of the non-cooperative attachment problem is demonstrated. On the Three-Axis Air-bearing Table, the non-cooperative attachment under different cases can be realized by placing different mass blocks with unknown inertia and unknown momentum at random time. Through the analysis of real output attitude, the control performance of the nonlinear adaptive controller are analyzed.