Fault diagnosis for discrete systems with delayed outputs

Observer-based fault diagnosis approach is researched for discrete systems with delayed outputs in this note. To solve the difficulty of fault diagnosis caused by delayed outputs of discrete systems, a discrete delay-free transformation approach is presented for delayed outputs, and the problem of fault diagnosis for discrete systems with delayed outputs is transformed into the problem of state observation of a discrete delay-free augmented system by constructing an augmented system and doing the delay-free transformations. A novel observer-based fault diagnosis approach is presented, which is different from the traditional observer-based fault diagnosis approaches by using residual to embody faults. Compared with the traditional observer-based fault diagnosis approaches, the proposed fault diagnoser has the faster response speed and higher accuracy. Finally, the feasibility and effectiveness of the proposed approaches are validated by a numerical example.