ℋ∞ observer-based control for discrete-time one-sided Lipschitz systems with unknown inputs

This paper investigates the problem of robust observer-based stabilization for a class of one-sided nonlinear discrete-time systems subjected to unknown inputs. We propose a simple simultaneous state and input estimator. A nonlinear controller is then proposed to compensate the effects of unknown inputs and to ensure asymptotic stability in closed loop. Several mathematical artifacts are used to deduce stability conditions expressed in terms of LMIs. To show high performances of the proposed technique, a relevant example is provided with comparisons to recent results.