Fault detection approaches for multirate-output sampled-data system with time delays

The fault detection problems of multirate-output sampled-data (MROSD) systems and MROSD systems with time delays are investigated. The main advantage of the approaches presented in this paper is that they can take into consideration the intersample behavior of such systems. The basic idea is to observe the dynamics of the system at fast sampling instants and then downsample the discrete-time outputs of this fast singe-rate sampled-data system according to different sampling rates and time delays. With the help of an operator proposed, the fault detection system can be designed in the framework of the parity space strategy. The application of the approaches proposed in this paper and their advantages in comparison with other indirect design approaches are finally illustrated by simulation examples.