Towards robust process fault estimation for uncertain dynamic systems

Abstract

The paper deals with the problem of simultaneous state and process fault estimation for uncertain dynamic systems. Contrarily to the approaches presented in the literature, the nonlinear estimation problem is reduced to the linear one by introducing a suitable system reparameterization and new estimator structure. Instead of estimating the fault directly, its product with state and the state itself are estimated. To tackle this problem, a robust design procedure is proposed that takes into account uncertainties acting onto the system being diagnosed. The approach is based on the quadratic boundedness approach allowing convergence analysis of uncertain systems with bounded uncertainties. Subsequently, a simple algebraic approach is proposed to derive the fault estimate. The final part of the paper shows a numerical example concerning state and pitch actuator component fault estimation of a wind turbine.