A fault-tolerant control design against major actuator failures: application to a three-tank system

This paper deals with a new fault-tolerant control method for nonlinear systems without hardware redundancy in a case of major actuator failures. The nonlinear law is achieved using an input-output linearization by state feedback. These failures correspond to a blocking or complete loss of an actuator which could lead to a large loss in the nominal performances. This method is based on the computation of new reference inputs in order to drive the system in an optimal operating order (optimal trim point for linear systems) with respect to desirable performances and to their degrees of priority. For a plant without actuator redundancies, it becomes of prime importance because it is impossible to maintain it at some acceptable level of performances in the presence of major actuator failures. The effectiveness of this approach is evaluated through the application to a nonlinear pilot plant, a three-tank system.