Active fault-tolerant control against actuator fault and performance analysis of the effect of time delay due to fault diagnosis

This paper discusses the problem of fault-tolerant control against actuator fault, derives the time spent at each steps in fault diagnosis which is called as the time delay due to fault diagnosis and quantitatively analyzes its effect on the faulty system’s performance. A fault diagnosis algorithm is first proposed. The proposed fault tolerant controller is designed to guarantees that all signals in the closed-loop system are semi-globally uniformly ultimately bounded, where the controller singularity is avoided without projection algorithm. What’s more, the analytical expression of the time delay is derived strictly. Further, the quantitative analysis of system performance which is degraded by the time delay is developed, and the conditions that the magnitudes of the faults should be satisfied such that the faulty system controlled by the normal controller remains bounded even stable during the time delay are derived. In addition, the corresponding solution to the adverse effect of the time delay is proposed. Finally, an experimental test shows that the proposed control algorithm has a very reliable efficiency.