Helicopter
Mostrando 1-12 de 18 artigos, teses e dissertações.
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1. Robust Optimal Adaptive Trajectory Tracking Control of Quadrotor Helicopter
Abstract This paper focuses on robust optimal adaptive control strategy to deal with tracking problem of a quadrotor unmanned aerial vehicle (UAV) in presence of parametric uncertainties, actuator amplitude constraints, and unknown time-varying external disturbances. First, Lyapunov-based indirect adaptive controller optimized by particle swarm optimization
Lat. Am. j. solids struct.. Publicado em: 2017-06
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2. Performance and Wake Analysis of Rotors in Axial Flight Using Computational Fluid Dynamics
ABSTRACT: Flow field around rotors in axial flight is known to be complex especially in steep descent where the rotor is operating inside its own wake. It is often reported that, in this flight condition, the rotor is susceptible to severe wake interactions causing unsteady blade load, severe vibration, loss of performance, as well as poor control and handli
J. Aerosp. Technol. Manag.. Publicado em: 2017-06
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3. Ambient Noise in Emergency Rooms and Its Health Hazards
Introduction The occupational risk due to high levels of noise in the hospital environment has been recognized, and the National Agency of Sanitary Surveillance of the Ministry of Health recommends evaluation and control of noise in hospital areas.
Objectives To assess the sound environment in the emergen
Int. Arch. Otorhinolaryngol.. Publicado em: 2015
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4. A New Coupled Free Wake-CFD Method for Calculation of Helicopter Rotor Flow-Field in Hover
ABSTRACT: This paper concerns a new coupled free wake-CFD method for proper calculation of aerodynamic loads on a two bladed helicopter rotor in hovering flight. Loading is computed by solving the three dimensional Euler equations in a rotating coordinate system. However, since direct simulation of the tip vortices and wake requires a very fine grid, the rot
J. Aerosp. Technol. Manag.. Publicado em: 2014-06
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5. First-year experience of a Brazilian tertiary medical center in supporting severely ill patients using extracorporeal membrane oxygenation
OBJECTIVES: The aim of this manuscript is to describe the first year of our experience using extracorporeal membrane oxygenation support. METHODS: Ten patients with severe refractory hypoxemia, two with associated severe cardiovascular failure, were supported using venous-venous extracorporeal membrane oxygenation (eight patients) or veno-arterial extracorpo
Clinics. Publicado em: 2012-10
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6. Anti-swing Controller Based on Time-delayed Feedback for Helicopter Slung Load System near Hover
Abstract: In this paper, a new anti-swing controller for helicopter slung load system near hover flight is proposed. This controller is based on time-delayed feedback of the load swing angles. The output from this controller is additional displacement that was added to the helicopter trajectory in the longitudinal and lateral directions. Hence, its implement
J. Aerosp. Technol. Manag.. Publicado em: 2012-09
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7. In-flight collision avoidance controller based only on OS4 embedded sensors
The major goal of this research was the development and implementation of a control system able to avoid collisions during the flight for a mini-quadrotor helicopter, based only on its embedded sensors without changing the environment. However, it is important to highlight that the design aspects must be seriously considered in order to overcome hardware lim
J. Braz. Soc. Mech. Sci. & Eng.. Publicado em: 2012-09
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8. Estimativa da atitude e posição e controle robusto de um helicóptero autônomo / Attitude and position estimation and robust control of an autonomous helicopter
Este trabalho aborda o estudo de um sistema de referência inercial de posição e atitude e um sistema de controle para um helicóptero autônomo utilizando, como base para formulação e testes, o modelo linearizado da aeronave Yamaha R-MAX. Um sistema de referência inercial (INS) e um sistema de referência de atitude e orientação (AHRS) são utilizado
Publicado em: 2010
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9. Construção de mosaicos georreferenciados usando imagens aéreas de pequeno formato
In this work we propose a technique that uses uncontrolled small format aerial images, or SFAI, and stereohotogrammetry techniques to construct georeferenced mosaics. Images are obtained using a simple digital camera coupled with a radio controlled (RC) helicopter. Techniques for removing common distortions are applied and the relative orientation of the mod
Publicado em: 2008
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10. Airborne geophysical and geological data applied to the selection of groudwater potential areas in crystalline rocks of Ceara, Brazil / Dados aerogeofisicos e geologicos aplicados a seleção de areas favoraveis para agua subterranea no dominio cristalino do Ceara, Brasil
The location of water well in Northeast Brazil is usually based on the interpretation of structural lineaments in aerial-photographs and electromagnetic and electrical resistivity ground geophysics surveys. However, the success of these techniques is variable, and the small coverage area is another limitation. This Thesis favors a different approach, the use
Publicado em: 2008
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11. Aeroservoelastic analysis of the blade-sailing phenomenon in the helicopter-ship dynamic interface.
This thesis proposes a Rotary-Wing Aeroservoelasticity approach to the modeling, analysis and control of the blade-sailing phenomenon in the helicopter-ship dynamic interface (DI), based on the identification, response evaluation and control of flow and ship motion induced loads, during the engagement/disengagement flight regimes, in order to establish some
Publicado em: 2007
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12. Application of time-delay neural and recurrent neural networks for the identification of a hingeless helicopter blade flapping and torsion motions
System identification consists of the development of techniques for model estimation from experimental data, demanding no previous knowledge of the process. Aeroelastic models are directly influence of the benefits of identification techniques, basically because of the difficulties related to the modelling of the coupled aero- and structural dynamics. In thi
Journal of the Brazilian Society of Mechanical Sciences and Engineering. Publicado em: 2005-06