Fault reconstruction/estimation using a sliding mode observer

This paper considers fault reconstruction and estimation issues for a class of nonlinear systems with uncertainty, using an equivalent output error injection approach. A particular design of sliding mode observer is presented, where the design parameters can be obtained using LMI techniques. For a special class of uncertainty, a fault reconstruction scheme based on this observer is described where the reconstruction signal can approximate the fault signal to any accuracy even in the presence of the uncertainties. A simulation study on a single-link flexible joint robot system is presented to show the effectiveness of the scheme.