Study of Nonlinear Integral Sliding Mode Fault-Tolerant Control

This paper studies an active fault-tolerant control (FTC) design based on an integral sliding mode control (ISMC) strategy for a class of uncertain nonlinear systems. It is shown that under the proposed scheme, the closed-loop system can tolerate certain allowable actuator faults whenever fault detection and diagnosis information is available, and the scheme also retains the main advantages of the ISMC technique. These advantages include robustness, rapid response, and ease of implementation. Moreover, the state response of the resulting closed-loop system under normal operation and different fault conditions is predictable from the response of a preselected fault-free certain system, which can be determined by the designer. Consequently, the engineer has the flexibility in selecting an (optimal) control law for the preselected system according to the system requirements. The analytical results obtained are also applied to the attitude control of a spacecraft. The simulation results clearly demonstrate the benefits of the proposed scheme.