Review on fault diagnosis techniques for closed-loop systems

Fault diagnosis for closed-loop systems is reviewed in this paper. The research background of fault diagnosis problem for closed-loop systems is introduced, and special attentions are paid to the study on the differences between fault diagnosis for open-loop systems and closed-loop systems. Existing fault diagnosis methods for closed-loop systems are also summarized. Some simulation examples are employed to illustrate the different fault diagnosis performances between typical open-loop systems and closed-loop systems. Finally, some challenging problems and promising research directions are pointed out.