On the problem of fault detection and residual generation

In this paper, the fundamental problem of residual generation is studied. The solution of this problem is the first step for the solution of the fault detection problem. Here, a class of nonlinear perturbed input-affine system is considered. The technique proposed is based on two steps: the first one consists of decoupling the perturbation with respect to the fault by using the technique of output injection; and the second one consists of fault detection by logic decision. A nonlinear observer with linearizable estimated error dynamics decoupled from the input and the disturbance is used as a residual generator. An illustrative example is presented