Fault detection of multirate sampled-data systems based on periodic system theory

This paper considers the problem of fast rate fault detection for multirate sampled-data systems. As a residual signal can only be generated at those time instants with sampled outputs, a new system description is obtained for the purpose of residual generation. Based on it, time-varying residual generators are designed, which take into account the intersample behaviour. Another important feature of the proposed design procedures is that they are readily applicable to the kind of non-uniformly sampled-data systems, where the sampling instants are non-equidistant spaced but periodic. The extension to the general non-uniformly sampled-data systems is straightforward.