An H∞ approach to fault estimation of non-linear systems: Application to one-link manipulator

The paper is focused on the problem of robust fault estimation of non-linear discrete-time systems. The general unknown input observer scheme and the H_∞ framework are applied to design a robust fault estimation methodology. The main advantage of the proposed approach is its simplicity resulting from the boiling down of designing methodology to solving a set of linear matrix inequalities, which can be efficiently done by the application of modern computational packages. The resulting approach guaranties that a prescribed disturbance attenuation level is achieved with respect to the fault estimation error while guaranteeing the convergence of the observer with a possibly large decay rate of the state estimation error. The final part of the paper presents an illustrative example regarding the application of the proposed approach to faults estimation of the one-link manipulator.