A cascade structure approach to control reconfiguration

Fault tolerant control (FTC) seeks to avoid the deterioration of the system at the time that there is a change of one or more parameters outside the limits of tolerance. There is in the literature a set of approaches based on the idea of tracking the nominal trajectory, which have been proved to be effective. However, some of them do not maintain the nominal controller, others, even if they keep it, require meet very demanding existence conditions. This paper proposes a fault recovery using a cascade control structure. The proposed design is based on the nominal trajectory tracking as well, but keeps intact the original control while existence conditions are relaxed. The resulting equivalent controller can be changed according to the performance needs of the system's response to faults. The controller could be defined by using stability regions and LMI tools.