The paper presents the use of modern state-space control theory in the design of an autopilot. The design utilizes an observer to determine the angle of attack of a tail-controlled vehicle and the application of the LQR technique to determine the state feedback gains. Computer modeling and simulation are used to evaluate the autopilot performances under different glide and boost conditions. The performances are compared with that from a conventional three-loop autopilot operating under similar flight conditions. Results indicated that the use of state feedback in the autopilot could enhance the vehicle performances under extreme glide and boost conditions.
Fok, S. C., Low, E., & Tan, S. H. (2000). Application of state feedback in an autopilot design. International Journal of Computer Applications in Technology, 13(6), 280–284. https://doi.org/10.1504/IJCAT.2000.000249