Application of the minimum state error variance approach to nonlinear system control

A class of modi®ed state space self-tuning controllers of the minimum state error variance type was considered. A suitable chosen structure of the proposed controller allows the tracking of a time-varying reference input and makes a possibility of applying this solution to nonlinear and non-stationar y plants. The advantage in using the proposed algorithm for nonlinear systems’ control is demonstrated through its application to aircraft control around a prespeci®ed reference trajectory in the presence of characteristic disturbances. The results show that the proposed controller has good tracking performance and possesses rather good immunity towards disturbances.