Robust MPC multicontroller design for actuator fault tolerance of constrained systems

In this paper, we present a robust actuator fault-tolerant control strategy for constrained linear systems, in the presence of bounded state and output disturbances. The scheme is based on a bank of state estimators which match different fault situations that can occur in the system. A fault detection and isolation (FDI) unit verifies that suitable residual variables lie inside pre-computed sets and selects the estimate that matches the current plant behaviour. A bank of robustly stabilising tube-based MPC control laws is designed, each associated to a fault scenario and the appropriate controller is selected among them using the information provided by the FDI module. By means of "tubes" of trajectories, we ensure robust closed-loop exponential stability of the constrained system and good performance in the fault-free case and under the occurrence of abrupt actuator faults.