Enhanced Linear Matrix Inequality Approach for Nonlinear Observer Design in Discrete-Time Systems

This paper presents two new Linear Matrix Inequality (LMI) conditions for designing H∞ observers for a class of nonlinear discrete-time systems in the presence of measurement noise or external disturbances. The proposed LMI conditions utilize reformulated Lipschitz properties, a new variant of Young's inequality, and the Linear Parameter Varying (LPV) approach to introduce more decision variables and enhance the feasibility of the LMI conditions compared to existing methods.