Robust control design of an automatic carrier landing system

A robust controller, utilizing H^∞control design techniques, is developed for an automatic carrier landing system. First, a detailed nonlinear aircraft simulation, which -includes the aircraft dynamics, pitch attitude autopilot, and automatic thrust compensator, is summarized. Then, impulse response data is used to form a time-invariant linear model approximation. This linear model is the plant used in the H^∞control design process. However, this plant has a pure integrator. Consequently, the H^∞control design formulation does not form a proper rational transfer function. A solution to this difficulty is developed by incorporating a simple feedback loop. With this modification, the robust control design is obtained A comparison study between the robust control design and the proportional- integral-derivativ-double derivative control law of the current carrier landing system is next shown. The design study indicates that the robust H^∞controller dramatically improves response characteristics and system performance.