Finite-Time Fault Estimation and Fault-Tolerant Control for Rigid Spacecraft

Abstract

This paper investigates a fault tolerant problem for the rigid spacecraft in the presence of additive faults and nonlinear disturbances. An adaptive observer and an adaptive terminal sliding mode observer (ATSMO) are presented respectively to distinguish the faults and external disturbances in finite time. Then, we develop a novel finite-time continuous terminal sliding mode controller (CTSMC) to compensate the detected faults. Unlike most of the existing online fault estimation, the proposed approach could achieve finite-time reconstruction of unknown faults and disturbances simultaneously, while the upper bound knowledge is unnecessary. Moreover, the proposed finite-time fault-tolerant controller (FTC) is only based on the information of available output and its first derivative. The effectiveness of the proposed methodology is demonstrated by simulation results.