Optimal helicopter station keeping

Linear optimal control techniques are used as a synthesis tool to conceptually design a control system for the Short Range Station Keeping (SRSK) task of a large assault helicopter. It is shown that linear optimal theory can be naturally applied to this problem because of the requirements for the closed-loop response of the system, and can be easily applied even though the vehicle is dynamically complex, requiring simultaneous inputs from more than one controller. The closed-loop dynamics are analyzed using the root square locus expression, and the feedback control law is obtained from the Riccati equation. Several designs are analyzed from a practical point of view, and a comparison is made of an optimal and a conventional design. When properly used, linear optimal control techniques may rapidly yield an excellent control system design.