Study on the design of unknown input estimators considering robust stability

Abstract

The design of a robustly stable unknown input estimator is considered in this paper. First, we derive a robust stability condition for the closed-loop system consisting of the plant and the unknown input estimator based on the small gain theorem. Then the derived condition is used in the parameter optimization process using the artificial bee colony algorithm. Finally, we confirm that we can design unknown input estimators with robustness against plant uncertainties through a numerical example.