Minimum sliding mode error feedback control and observer for satellite attitude control and determination

Abstract

This paper proposes a new controller and observer (minimum sliding model error feedback control/observer, MSMEFC/O) for the attitude control and determination systems (ACDS) of satellite. It is known that the ACDS plays a significant role in the overall performance of a satellite system, especially under the influence of uncertain disturbances from the space. It is clear that any controller and observer with the capacity to deal with uncertain disturbances will improve the performance of ACDS. It is shown that the proposed MSMEFC, based on the new concept of “equivalent control error”, can compensate for various kinds of uncertain disturbances. In addition, the relationship between the equivalent control error and the uncertain disturbances is described. The robustness and steady-state error corresponding to MSMEFC are investigated to show its theoretical advantages over the traditional sliding mode control. Furthermore, the minimum sliding mode error feedback observer is also proposed based on the theory of MSMEFC. Finally, the new MSMEFC/O concept is applied to satellite ACDS, which guarantees global asymptotic convergence of attitude control and determination with high accuracy. Numerical simulations are performed to show the efficacy of the proposed MSMEFC/O in the presence of severe uncertain disturbances.