A universal Chow-Willsky scheme and detectability criteria

An important issue in diagnosis research is design methods for residual gen eration. One method is the Chow-Willsky scheme. Here, the Chow-Willsky sche me is extended as it becomes universal in the sense that, for both discrete and continuous linear systems, it Is shown to be able to generate all poss ible parity functions. This result means it can also be used to design all possible residual generators. It is shown previous extensions to the Chow-W illsky scheme are not universal, which is the case when dynamics controllab le from fault exist, but not from the inputs or disturbances. Also included here are two new conditions on the process for fault detectability and str ong fault detectability. A general condition for strong fault detectability has not been presented elsewhere.