Global ETD Search

1	Helicopter mission and rotor performance optimization with quasi-linear inflow theory Khan, Azhar Mansur 12 1900 (has links) No description available. Helicopters Aerodynamics Stability of helicopters
2	An investigation of helicopter individual blade control using optimal output feedback Wasikowski, Mark E. 12 1900 (has links) No description available. Helicopters Aerodynamics Helicopters Control systems Stability of helicopters
3	A preliminary design to include a stability and control study in hovering flight of a laterally disposed, single-bladed, counter-rotating, two-rotor helicopter with shrouded tail propeller Ellis, William Roderick 12 1900 (has links) No description available. Helicopters Design and construction Rotors (Helicopters) Aerodynamics Stability of helicopters
4	Helicopter stability during aggressive maneuvers Unknown Date (has links) The dissertation investigates helicopter trim and stability during level bank-angle and diving bank-angle turns. The level turn is moderate in that sufficient power is available to maintain level maneuver, and the diving turn is severe where the power deficit is overcome by the kinetic energy of descent. The investigation basically represents design conditions where the peak loading goes well beyond the steady thrust limit and the rotor experiences appreciable stall. The major objectives are: 1) to assess the sensitivity of the trim and stability predictions to the approximations in modeling stall, 2) to correlate the trim predictions with the UH-60A flight test data, and 3) to demonstrate the feasibility of routinely using the exact fast-Floquet periodic eigenvector method for mode identification in the stability analysis. The UH-60A modeling and analysis are performed using the comprehensive code RCAS (Army's Rotorcraft Comprehensive Analysis System). The trim and damping predictions are based on quasisteady stall, ONERA-Edlin vi (Equations Differentielles Lineaires) and Leishman-Beddoes dynamic stall models. From the correlation with the test data, the strengths and weaknesses of the trim predictions are presented. / by Ranjith Mohah. / Thesis (Ph.D.)--Florida Atlantic University, 2012. / Includes bibliography. / Electronic reproduction. Boca Raton, Fla., 2012. Mode of access: World Wide Web. Helicopters--Aerodynamics Helicopters--Control systems Rotors (Helicopters)--Aerodynamics Stability of helicopters Vibration (Aeronautics)--Damping
5	Development and validation of a tire model for a real time simulation of a helicopter tranversing and manoeuvring on a ship flight deck / Tremblay, Jason January 1900 (has links) Thesis (M.App.Sc.) - Carleton University, 2007. / Includes bibliographical references (p. 108-112). Also available in electronic format on the Internet.
6	Efficient ranging-sensor navigation methods for indoor aircraft Sobers, David Michael, Jr. 09 July 2010 (has links) Unmanned Aerial Vehicles are often used for reconnaissance, search and rescue, damage assessment, exploration, and other tasks that are dangerous or prohibitively difficult for humans to perform. Often, these tasks include traversing indoor environments where radio links are unreliable, hindering the use of remote pilot links or ground-based control, and effectively eliminating Global Positioning System (GPS) signals as a potential localization method. As a result, any vehicle capable of indoor flight must be able to stabilize itself and perform all guidance, navigation, and control tasks without dependence on a radio link, which may be available only intermittently. Since the availability of GPS signals in unknown environments is not assured, other sensors must be used to provide position information relative to the environment. This research covers a description of different ranging sensors and methods for incorporating them into the overall guidance, navigation, and control system of a flying vehicle. Various sensors are analyzed to determine their performance characteristics and suitability for indoor navigation, including sonar, infrared range sensors, and a scanning laser rangefinder. Each type of range sensor tested has its own unique characteristics and contributes in a slightly different way to effectively eliminate the dependence on GPS. The use of low-cost range sensors on an inexpensive passively stabilized coaxial helicopter for drift-tolerant indoor navigation is demonstrated through simulation and flight test. In addition, a higher fidelity scanning laser rangefinder is simulated with an Inertial Measurement Unit (IMU) onboard a quadrotor helicopter to enable active stabilization and position control. Two different navigation algorithms that utilize a scanning laser and techniques borrowed from Simultaneous Localization and Mapping (SLAM) are evaluated for use with an IMU-stabilized flying vehicle. Simulation and experimental results are presented for each of the navigation systems. Rotorcraft Sensor Dilution Helicopter Precision Scanner Wall Obstacle Flight Coaxial Quadrotor Stabilization Indoor Sonar Mapping UAV MAV Autonomous Aircraft Guidance Navigation Control Indoor Laser Inertial SLAM Localization Infrared Detectors Stability of helicopters Aerodynamics Proximity detectors

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