Robust H∞ hybrid estimation for continuous linear time-varying uncertain systems with known input

This letter presents an approach to deal with robust H_∞ state and input hybrid estimation for continuous linear time-varying systems, where norm-bounded parameter uncertainty is appeared in the state and output matrices and a known input is incorporated in the state-space model. The known input will influence the estimation due to parameter uncertainty. Using differential game theory approach, a sufficient solvable condition for the problem is proposed as well as a design method for the optimal estimator. Compared with those based on nominal systems, the proposed approach significantly improves the estimator´s robustness to parameter uncertainty and known input. One simulation example about a second-order resonant system illustrates the effectiveness of such an approach.