An observer-based controller for nonlinear systems: A gain scheduling approach

This paper presents an observer-based controller for discrete-time nonlinear systems whose control inputs are subject to a set of equality and/or inequality constraints. Firstly, a regularized least-square estimator is developed to estimate the states of the nonlinear system. Then, the estimated states are used to generate a feedback control law using the Jacobean linearization in conjunction with gain scheduling. The stability of the closed loop control system is rigorously investigated. Applications of the proposed observer-based control scheme to two numerical examples are presented. Then, the developed controller is used to control a synchronous machine which is subject to constraints on the control. The simulation results show the effectiveness of the proposed observer-based control scheme.