Advanced Flight Controls for Ultra-agile Small Unmanned Air Vehicles

Significant resources are required to ensure precision of flight control laws over the large flight envelope of modern aircraft. This is often compounded, when vehicle parameters change due to payload modifications, system upgrades, and degradation or failure of actuation systems. In the case of a multi-flight-mode aircraft capable of vertical take-off and landing (VTOL) and cruise flight, the vehicle control challenge extends well beyond parameter changes. Although, flight control systems have been successfully designed separately for rotary-wing and fixed-wing application, the conversion phase in which the aircraft operates"in between"helicopter and airplane mode still poses a significant challenge. To close this technological gap, the NextGen team proposes the development of a nonlinear robust (NLR) control framework that utilizes a state predictor capable of emulating the vehicle dynamics in real time. Thus, required fidelity of modeling data, re-study of the algorithm due to payload changes, and risk to the aircraft due to uncertainties within the vehicle"s aerodynamics during conversion can all be significantly reduced. The NextGen team will demonstrate the controller"s expected benefits through a series of simulations in Phase I and flight demonstrations in Phase II using a Spinwing aircraft which is currently developed under NAVY STTR funding.