Long-Endurance, Autonomous Vehicle Control

The proposed work, through Phase II, is intended to develop an autonomous flight control system for the High Altitude Airship (HAA). Given the problem's complexity, the proposed Phase I work will be focused on a limited number of issues that criticallyimpact the feasibility of HAA flight control. Many of these are related to station keeping in winds and turbulence at the stratospheric operating altitude. Control power limits, particularly for the propeller thrusters, and the distinctive aerostaticsand aerodynamics of the airship, specifically its unique response to unsteady gusts, will be Phase I focal points. The Phase I work will begin with an examination of the mission, its functional requirements, and a definition of a representative HAAconfiguration. Aerostatic, aerodynamic, propulsion and mass properties characteristics will then be obtained or estimated and used to implement a basic dynamic model of the HAA. Flight mechanical and trim analyses will then be conducted with emphasis onidentification of potential control power problems. Next dynamic analyses will be performed to examine modal characteristics and response to control and disturbances with emphasis on unsteady gusts. Finally, a candidate inner loop flight control systemto meet the appropriate requirements will be synthesized and assessed. The proposed autonomous flight control research and development will be directly applicable to the development of the HAA for military applications such as missile warning and maritimesurveillance and control and for commercial applications such as telecommunications.