Accepting performance degradation in fault-tolerant control system design

A novel fault-tolerant control system design technique has been proposed in this paper, which blends the multiple-model principle with the unavoidable performance degradation due to faults in actuators, sensors or system dynamics. The number of models employed depends on the characteristics of the system, the nature of the failures considered, and the physical limits of system variables. The achievable performance under various component failures are represented in the form of reference models, known as performance reduced reference models. These models are used to synthesize a set of controllers. Under a specific fault condition, proper controller and revised control system command input are selected automatically to achieve desired performance. A simulation example of an aircraft subject to different type of failures has been used to illustrate the design process and to demonstrate the effectiveness of the method.