Linear Fractional Transformation Control Of The F-14 Aircraft Lateral-Directional Axis During Powered Approach Landing

This paper presents the design of a linear fractional transformation (LFT) gain-scheduled controller, scheduled on angle-of-attack, for the F-14 aircraft lateral-directional axis. The controller is designed for the powered approach flight envelope during which angle-of-attack/airspeed variations range from 2 degrees/182 knots to 14 degrees/126 knots. A linear fractional model of the lateral dynamics is constructed based on four linearized models that correspond to 2, 6, 10.5, and 14 degrees angle-of-attack. The resulting LFT controller performs well when implemented in a Simulink nonlinear simulation of the F-14 aircraft.