A Novel Framework of Cooperative Design: Bringing Active Fault Diagnosis Into Fault-Tolerant Control

Fault-tolerant control (FTC) may conceal fault symptoms, thereby increasing the difficulty of fault diagnosis (FD). In this article, a novel framework for the cooperative design of active FD and FTC is proposed to optimize FD performance while maintaining fault-tolerance performance. The proposed framework consists of four steps: 1) controller design; 2) residual generation; 3) performance evaluation; and 4) gain tuning. First, a controller with undetermined gains is constructed, and a fault detection observer is designed to generate residuals that can indicate the fault. Then, the performance of fault detection is evaluated. Finally, suboptimal controller gains are obtained by solving an optimization problem. Within the framework of the collaborative design, the occurring faults can be detected faster and more accurately, and the performance of FTC can be guaranteed at the same time. A simulation study is provided to demonstrate the effectiveness of the developed framework.