ABSTRACT MODEL AND CONTROLLER-DESIGN FOR AN UNSTABLE AIRCRAFT

In this paper, we consider an unstable system with a time delay as an abstract model of an aircraft longitudinal motion for the short period. In our controller design we want both sensitivity reduction and robustness to certain unmodeled dynamics. Using standard arguments, these control objectives are formulated as an H infinity optimal control problem. We show in detail how to compute the optimal controller for this distributed model (and not for a finite dimensional approximation). A numerical example is given to illustrate the computational procedure. Certain properties of the controller are discussed for this example.