Performance characteristic of an Unmanned Air Vehicle (UAV) is investigated using a newly developed heuristic approach. Almost all flight phases of any air vehicle can be categorized into trim and maneuvering flights. In this paper, a new envelope called trim-ability envelope, is introduced and sketched within the conventional flight envelope for a small UAV. Optimal maneuverability of the inte...

The design and simulation of an on-line algorithm which estimates the safe maneuvering envelope of aircraft is discussed in this paper. The trim envelope is estimated using probabilistic methods and efficient high-fidelity model based computations of attainable equilibrium sets. From this trim envelope, a robust reachability analysis provides the maneuverability limitations of the aircraft thro...

Automatic trajectory planners require knowledge of an aircraft’s flight envelope to ensure their solution is feasible. Existing flight management systems presume a nominal performance envelope, requiring online identification or characterization of any performance degradation. Given predictable failures such as a control surface jam, we can evaluate stability and controllability offline to esta...

W IND disturbances are a common factor in aviation accidents. Among 126 airplane accidents that occurred between 1979 and 2009 involving loss of control in flight, 14% listed windshear, turbulence, or thunderstorms as a cause or contributing factor. Moreover, 86% of the accidents initiated by atmospheric disturbances led to an upset flight condition, which usually entails an excursion of the ai...

Based on the feature of model disturbances and uncertainty being compensated dynamically in auto – disturbances-rejection-controller (ADRC), a new method using ADRC is proposed for the decoupling control of dispenser longitudinal movement in big flight envelope. Developed from nonlinear model directly, ADRC is especially suitable for dynamic model that has big disturbances. Furthermore, without...

The flight envelope can be viewed as a set within the state space of an aircraft. For various safety considerations an aircraft is required to remain within its prescribed flight envelope. The safe set is the largest controlled invariant set within the flight envelope. Thus, if an aircraft is to remain within its envelope it must stay within the safe set. When an aircraft is impaired, e.g., a j...

Launch and recovery helicopter wind envelope for a ship type was determined as the first step to the helicopter qualification program. Flight deck velocities data were obtained by means of a two components laser Doppler anemometer testing a 1/50 model in the wind tunnel stream. Full-scale flight deck measurements were obtained on board the ship using a sonic anemometer. Wind tunnel and full-sca...

Hybrid unmanned aircraft, that combine hover capability with a wing for fast and efficient forward flight, have attracted a lot of attention in recent years. Many different designs are proposed, but one of the most promising is the tailsitter concept. However, tailsitters are difficult to control across the entire flight envelope, which often includes stalled flight. Additionally, their wing su...

To ensure flight safety, extensive flight-testing and active structural servo control strategies are required to explore and expand the boundary of a flight envelope. Aeroservoelastic (ASE) models can provide online flight monitoring of dynamic instabilities to reduce flight time testing and increase flight safety. The reliability of an ASE model for the flight envelope prediction and flight sa...