Design of optimal preview controller for terrain-following flight

We adopted optimal preview control methodology to design a terrain-followin g controller for a cruise missile. In this methodology, tracking errors and control increments are both considered in a quadratic penalty function. An augmented error system that involves future command inputs is built. Thus the preview control problem can be formulated as an optimal regulator probl em. Integrating the general optimal servo system with preview feed-forward compensations that respectively feed forward future command inputs and futu re disturbances produces an optimal preview servo system. In the terrain-fo llowing system, the flight altitude of a cruise missile is the command inpu t, and its future information can be known a priori. The wind is viewed as the disturbance in the system and is not previewable. Thus we designed a te rrain-following controller with a basic state feedback and a feed-forward c ompensation for future altitude information, regarding the wind as a consta nt signal. Simulation results show that the performance of the terrain-foll owing system with such an optimal preview controller is improved dramatical ly.