Actuator fault tolerant control of systems with polytopic uncertainties using set-based diagnosis and virtual-actuator-based reconfiguration

In this paper, a robust actuator fault tolerant control (FTC) strategy for systems with polytopic uncertainty is proposed. Two types of model descriptions are investigated in this work: convex polytopic model uncertainty and linear-parameter-varying (LPV) convex polytopic model uncertainty; where, in the latter, the varying parameter is assumed to be measured. The proposed FTC strategy combines a robust fault detection and isolation (FDI) approach based on set separation with controller reconfiguration based on the use of a bank of virtual actuators (VA). Both, FDI and controller reconfiguration modules, use the same bank of VA. The robust FDI method is based on the separation of relevant sets defined for measurable residual signals, which are computed using the VA signals and taking into account system disturbances and model uncertainty. The closed-loop system is reconfigured by means of a VA which is adapted to the fault situation detected by the FDI unit. The performance of the resulting robust FTC scheme is analysed for the two types of model descriptions by means of a simulation example.