Component Failure Detection Using Local Second-Order Observers

This paper presents a component failure detection scheme based on analytical redundancy. The redundant signals are generated by state estimation using local second-order observers that are designed for each component of a given nonlinear process. The scheme may be considered as a generalization for a class of nonlinear systems of the method proposed by Jansen and Frank (1984, 1986) for linear or linearized systems. The introduction of the nonlinearities of the process into the structure of the observers contributes to improve the efficiency of the failure location scheme. Some results of a digital simulation illustrate the method in the context of an example.