An NDO-Based Adaptive Slide Mode Control Method with Prescribed Settling Time and Its Application in the Integrated Orbit & Attitude Control of Spacecraft

Abstract

AbstractThis paper mainly concentrates on the adaptive sliding mode (SM) control problem for a class of second-order nonlinear systems afflicted with external disturbances. By introducing the nonlinear disturbance observer (NDO) methodology, a new adaptive function augmented sliding mode (FASM) control method is obtained. It has been reported that even when there is no NDO, the controller can make the control error converge to the prescribed neighborhood of zero in the prescribed settling time. When the NDOs are introduced, not only the aforementioned objective can be achieved, but also the external disturbances can be well compensated for, which helps to improve the control precision. This proposed method is finally applied to the integrated orbit and attitude (IO&A) control of spacecraft in the approaching and tracking stage, and the simulation result shows the validity of our results.KeywordsSliding mode controlPreassigned settling timeNonlinear Disturbance ObserverIntegrated orbit and attitude control