Gain-Scheduled Lateral Control of the F-14 Aircraft during Powered Approach Landing

Abstract

The design of a linear fractional transformation gain-scheduled controller, scheduled on angle of attack, for the F-14 aircraft lateral-directional axis is presented. The controller is designed for the powered approach flight phase, during which the angle of attack and corresponding airspeed varies from 2 deg and 182 kn to 14 deg and 126 kn. A linear fractional model of the lateral dynamics is constructed based on four linearized models that correspond to 2, 6, 10.5, and 14 deg angle of attack. Using parameter-dependent functions, a controller is designed that depends in a linear fractional manner on angle of attack and delivers uniform handling quality over angle-of-attack variations that lie between 2–14 deg. The resulting controller performs well when implemented in a nonlinear simulation model of the F-14 aircraft.