Active Fault Tolerant Control for Flexible Spacecraft with Sensor Faults Using Adaptive Integral Sliding Mode

Abstract

In this paper, an active fault tolerant attitude control system is provided for a flexible spacecraft to accommodate the unknown sensor faults. Firstly, a model-based fault estimation technique developed into the process behavior by using a virtual filter and an adaptive observer, and then estimating the amplitude magnitude for the faulty sensor in the presence of system disturbance and parameter uncertainty. Next, reconfigurable attitude controller is developed by combining both integral sliding mode control and linear matrix inequality technique. Meanwhile, the stability of the closed loop attitude systems under the designed active fault tolerant control (FTC) scheme is analyzed by utilizing Lyapunov approach. Finally, the effectiveness of the proposed fault tolerant scheme has justified by simulation result on a flexible spacecraft attitude control systems with a time varying sensor fault.