An output integral sliding mode FTC scheme using control allocation

In this paper, a new fault tolerant control scheme is proposed for systems where only output information is available. The ideas of integral sliding mode control are used to ensure robustness throughout the entire response of the system, even in certain actuator fault/failure cases. This is accomplished by integrating fixed control allocation within this ISM framework. An unknown input observer is included in the proposed scheme to estimate the states, as it is assumed that there is no information of the true states or knowledge of the faults or failures from a monitoring scheme. A rigorous closed-loop stability analysis is presented, and in fact, a convex representation of the problem is formulated to synthesize a controller. Simulation results on a benchmark civil aircraft model show good tracking of the commanded signals.