Fault estimation for a class of non‐linear systems via full‐column‐rank state variable substitution

Abstract

The problem of fault estimation for a class of non-linear systems with Lipschitzian non-linearities and faults is studied. In most of the existing fault estimation methods, the coefficient matrix of the fault vector is required to be full column rank, which leads to that the corresponding estimation approaches are conservative and unsuitable commonly for systems with multiple faults or/and subject to disturbances. In this study, this restriction is relaxed. A novel fault estimation method is proposed, where a full-column-rank state variable substitution is introduced so as to meet the requirement of fault estimation. The designed estimation observer guarantees the asymptotic stability of the overall error system with a prescribed H∞ performance. The states and faults can be estimated with good accuracy simultaneously. Then, the proposed estimation approach is further extended to solve the problem of fault estimation for non-linear systems with multiple faults or/and subject to disturbances. Finally, numerical examples illustrate the effectiveness and advantages of the proposed method.