The AOA was tightly controlled as the scramjet performance was dependent on AOA. It used inertial AOA in a classical loop structure.[^1] It was designed using a root-locus method using sequential loop closure.[^1] The gains were a function of mach number and AOA with a compensation for dynamic pressure.[^1] It used feedforward elements to minimize known disturbances.[^1] 2 seconds after the closure of the cowl and throughout the descent, the controller was a simple acceleration controller.[^1] The equivalent AOA was software limited.[^1] In this mode the only feedforward command path was the AOA.
The AOA to elevator feedforward schedule resulted in a lower AOA trim value. As there is no proportional feedback in the alpha controller, and the trim error was removed by the integrator.
Sources
- C. Bahm, E. Baumann, J. Martin, D. Bose, R. Beck, and B. Strovers, “The X-43A Hyper-X Mach 7 Flight 2 Guidance, Navigation, and Control Overview and Flight Test Results,” in AIAA/CIRA 13th International Space Planes and Hypersonics Systems and Technologies Conference, Capua, Italy: American Institute of Aeronautics and Astronautics, May 2005. doi: 10.2514/6.2005-3275.
Backlinks
[[Acceleration Autopilot]]
[[Angle of Attack]]
[[Dynamic Pressure]]
[[Feedforward Control]]
Gain Scheduling
[[Lead and Lag Compensators]]
[[Root-Locus Plots]]
[[X-43 Flight Control Laws]]