Abstract
In this research, we propose a scheme to control the altitude of an unmanned small rotorcraft. Several H_∞, controllers can be designed to stabilize the rotorcraft at desired height respectively in consideration of the nonlinear characteristics. We introduce several domains of attraction in the state space of the system concerning the H_∞ controllers. When any initial point is selected in one of these domains, the system can be stabilized by the corresponding H_∞ controller. In order to perform the altitude control of the flying rotorcraft, we present a switching control law with these H_∞ controllers. The feasibility of the presented scheme is verified through experiments.
