The Naval Postgraduate School is developing an vertical take-off and landing (VTOL) unmanned air vehicle (UAV) that can transition to horizontal flight, once airborne, in order to take advantage of the improvements in speed, range, and loiter time that horizontal, fixed-wing flight provides. This research investigates the design requirements of the central controlling device for that UAV, including the specific problems of defining the necessary hardware components and developing software for executive control. First, hardware requirements needed to be determined. By exploring the general operational requirements of the UAV and taking into account space and weight limitations, a hardware suite was selected which could provide adequate functionality to replace the human traits of a pilot. Its order to provide awareness' of the operational environment, motion sensors, navigation equipment, and communication equipment was required. Controllable servo motors were necessary to move control surfaces appropriately. Computer hardware, necessary to provide system intelligence, was selected in order to interoperate with the other hardware. Next, a Real-Time Executive (RTE) software program was designed to provide the functionality and coordination of all hardware components. Device drivers for each component were developed, and overall coordination was planned using a Yourdon style essential model. Periodic interrupts were used to control execution time. Last, the specifications and configuration of all hardware components were completely documented, and the operation of the RTE program is fully explained. From this understanding of the overall control system, future development can continue, resulting in a more effective and efficient UAV design.
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