A Model Reference Adaptive Re-Entry Flight Control System

The pitch plane equations of motion of a rigid body maneuvering ballistic re-entry vehicle are reviewed. A quasi-linear analysis of these equations is made about a nominal re-entry trajectory. It is demonstrated that in a large number of cases constant gain compensation for the flight control system will not be satisfactory due primarily to variations in dynamic pressure and static margin. A brief review of the adaptive concept is presented. It is shown that a model reference adaptive feedback system which has lift acceleration as the controlled variable and pitch rate as a stabilizing feedback is capable of handling the re-entry control problem. Current research involving fast identification techniques is described