Fault tolerant control of systems with polytopic uncertainties based on virtual sensor reconfiguration

In this paper, a robust sensor fault tolerant control strategy for systems with convex polytopic model uncertainty is proposed. The strategy combines a robust fault detection and identification (FDI) unit based on an invariant-set approach with controller reconfiguration based on the use of a virtual sensor. The robust FDI unit employs a bank of observers that can detect faulty and healthy situations based on the separation of relevant sets, whose computation takes into account system disturbances and model uncertainty. The closed-loop system is reconfigured by means of a virtual sensor which is adapted to the fault situation detected by the FDI unit. The FDI and virtual sensor modules are designed using polytopic techniques and bilinear matrix inequalities. The performance of the resulting robust fault tolerant control scheme is analysed in terms of reference tracking and controller reconfiguration under a range of sensor fault scenarios. The applicability of the proposed scheme is illustrated by a simulation example.