Output derivative free design of unknown input plus state functional observer
Proceedings of the American Control Conference
We consider problem of state function as well as unknown input estimation using only measured outputs of a linear time-invariant system. Two separate reduced-order input estimators using the same design methodology are proposed. The first is extension of full-order state/input estimator previously reported in the literature. The second is based on adaptive observer technique. The main achievement of the paper is that our proposed observer estimates a function of the state as opposed to the actual state, and as a result can be designed under less restrictive conditions than that of the state observers. Also, the proposed observer can be designed for certain non-minimum phase systems.
Xiong, Yi and Saif, Mehrdad. (2000). Output derivative free design of unknown input plus state functional observer. Proceedings of the American Control Conference, 1, 399-403.