Fault estimation for nonlinear systems by an intermediate estimator with stochastic failure

In this paper, the problem of fault estimation for a kind of nonlinear systems with Lipschitzian nonlinearities is considered. A new fault estimation approach is proposed, where a stochastically intermediate variable is introduced. Based on the expectation of such a variable exactly available, a kind of intermediate estimator is proposed to estimate the state and fault simultaneously. As for a case that its probability is uncertain, the effects are also considered in detail. Different from the traditional fault estimation methods, the algorithm proposed here could bear stochastic failure and is without observer matching condition, which also has less conservatism. The simulation of a practical example is exploited to demonstrate the effectiveness and superiority of the proposed methods.