Progressive accommodation of actuator faults in the linear quadratic control problem

The solution of the linear quadratic problem under actuator faults is investigated. Both fault accommodation and system reconfiguration procedures need the controller to be re-designed, which means solving the algebraic Riccati equation (ARE) associated with the faulty system model. A progressive accommodation strategy, based on the Newton-Raphson scheme for solving the ARE is proposed, and it is shown that it significantly reduces the risk associated with system instability and/or control inadmissibility which result from fault detection and isolation delay, and computation time of the accommodated control.