Terminal control system applications

This paper describes a synthesis procedure for terminal control systems. The synthesis procedure is illustrated by application to the design of an aircraft automatic landing system. A simplified model for the landing aircraft is chosen and justified. The prediction equations for this model are discussed. Using the prediction equations, a two-condition terminal controller, which controls the altitude and altitude rate at time of touchdown to the desired values, is developed. The terminal control landing system developed is simplified by combining feedback loops in a straightforward fashion to arrive at a practical mechanization. A stability analysis of the simplified terminal controller, considered as a servo with time variable gains and time constants, is presented. The results of extensive analog computer simulation and flight test of the terminal control landing system developed in this paper are reviewed. It is shown that the synthesis procedures developed in this paper result in a system which can be implemented by state-of-art hardware to land aircraft successfully.