Automatic landing control using H∞ control and stable inversion

This paper presents a new method for developing robust tracking controllers for automatic landing systems. We first develop a linearized longitudinal model of the Boeing 747 commercial airplane together with models for the control actuators, wind gust, and wind shear. The H_∞ control provides robust stability against uncertainties caused by exogenous disturbances and signals noise. The stable inversion provides precision tracking. Both methods are integrated to satisfy both robust and exact tracking requirements for the automatic landing system. Based on the stable inversion technique, the desired altitude and airspeed trajectories are also designed. The numerical simulation results show that the proposed automatic landing system can exceed FAA (Federal Aviation Administration) requirements for Category III precision approach landing. Furthermore, the integrated system can achieve robust accurate tracking in the presence of measurement noises, wind gust, and wind shear with middle intensity. Compared with existing approaches, our method achieved higher precision with excellent robustness