Performance-Based Fault-Tolerant Control Uniformly Accommodating Multiple Levels of Actuation Failures

Most existing fault-tolerant control schemes either are contingent upon timely and accurate fault identification or need to be redesigned whenever the types/phases of actuator failures change, rendering the control design rather complex. In this work, a dynamic hardware redundancy technique with a performance-based trivial fault detector is proposed to accommodate multiple levels of actuator failures, upon which a unified performance-based fault-tolerant control scheme is developed irrespective of different phases of actuator failures. The proposed fault-tolerant control exhibits several salient features, which include the following: by choosing appropriate performance functions, the controller is developed under a unified control structure against different actuation phases ranging from healthy actuation and moderate failure actuation to post extreme failure actuation; the faulty actuator is replaced with the backup one only in the event of extreme failures, avoiding the unnecessary replacement during moderate actuation failure; and without the need for neural networks or fuzzy systems based approximation, the resultant control scheme is simple in structure and inexpensive in computation.