A NONLINEAR FLIGHT CONTROLLER-DESIGN FOR AIRCRAFT

In this paper, a nonlinear flight controller design approach using the method of extended linearization is described and applied to an F-8 a ircraft longitudinal model. Performances of both gain-scheduled and th e nonlinear controllers are compared using simulation studies. The res ults indicate that the nonlinear controller is insensitive to the choi ce of scheduling variable, and returns all the state variables to thei r respective trim conditions under large initial deviations in angle o f attack, while the gain-scheduled controllers fail to do so. In gener al, the proposed nonlinear control design gives better performance and removes some of the difficulties in the conventional gain-scheduling approach.