Robust fault and state estimation for Lipshitz systems: Three-tank system application

The paper deals with robust fault estimation problem for non-linear discrete-time Lipschitz systems and robust state observer design. Proposed fault estimation strategy is based on Unknown Input Observer and H_∞ general frameworks, which are used to formulate robust fault and state observer problem. The prescribed disturbance attenuation level is achieved, while guaranteeing convergence of the observer by solving H_∞ robust observer problem. The DMVT is proposed to deal with nonlinearities by assuring that non-linear function is outer-bounded. The overall problem is described by set of linear matrix inequalities, which are efficiently handled by freely available solvers. In the final part illustrative example is presented in order to validate proposed approach on three-tank system.