Linearization techniques in fault diagnosis of non-linear systems

In this paper it is shown how the well-known linearization technique can be used to solve the problem of fault diagnosis, for non-linear systems subject to actuator failures. An exponential adaptive observer is designed on the basis of the first approximation approach, achieving locally exponential convergence of observation error as well as unbiased fault diagnosis. A link between linear fault diagnosis and its non-linear counterpart is explored. The effectiveness of the proposed non-linear fault diagnosis scheme is illustrated through a simulation example.