Results 61 to 70 of about 189,925 (269)

Design of an Adaptive Landing Gear with Ground Contact Sensing Capability

Nanjing Hangkong Hangtian Daxue Xuebao
To improve the landing capability of helicopters on complex terrain， this paper proposes an adaptive landing gear with ground contact sensing capability.
LI Qi, MIAO Hongtao, YANG Yun
doaj   +1 more source

Moisture inversions in the central Arctic: Product assessment and long‐wave radiative effect

Quarterly Journal of the Royal Meteorological Society, EarlyView.
This study evaluates the integrated water vapour and the vertical distribution of water vapour of state‐of‐the‐art reanalyses, weather forecast models, and ground‐ and space‐based remote‐sensing products in the central Arctic. A particular focus lies on the representation of humidity inversions and the quantification of the long‐wave radiative effect ...
Andreas Walbröl, Susanne Crewell, Carola Barrientos‐Velasco, Giovanni Chellini, Hannes J. Griesche, Janna E. Rückert, Kerstin Ebell   +6 more
wiley   +1 more source

Decision-making support system of civil helicopter maritime search and rescue for people in distress

Hangkong gongcheng jinzhan
Helicopter maritime search and rescue（MSAR）is one of the important components in aviation emergency rescue system. However，the MSAR unit usually analyzes distress information and makes response plans according to previous experience，which lacks the ...
CHEN Zikun
doaj   +1 more source

Scoop attachment makes helicopter recoveries easier and safer [PDF]

, 1965
Helicopter with rigid boom and net attachment performs rescue or recovery operations easily and safely. The attachment in the front of the helicopter scoops objects from difficult and otherwise inaccessible areas and pivots to the side hatch of the ...
Koons, W. E.
core   +1 more source

Neural Network‐Based Adaptive Super‐Twisting Control for Perturbed Nonlinear Systems: Lyapunov Design

International Journal of Robust and Nonlinear Control, EarlyView.
ABSTRACT A newly developed robust control strategy based on an adaptive neural network (ANN) estimator performed in concert with adaptive super‐twisting (ASTW) control is presented. The proposed adaptive robust control algorithm is applied to a class of perturbed nonlinear systems and features a significantly decreased control gain with respect to the ...
Mohammad Javad Mirzaei, Mohamed Assaad Hamida, Yuri Shtessel, Franck Plestan   +3 more
wiley   +1 more source

Influence of Smart Spring Support Parameters on Vibration Characteristics of Three Support Shafting

Applied Sciences, 2020
Smart spring support is a kind of active damping device based on piezoelectric material. It can effectively suppress the vibration of a shaft system in an overly critical state by changing the stiffness and damping of the support.
Miao-miao Li, Liang-liang Ma, Chuan-guo Wu, Zhuo Li, Ru-peng Zhu   +4 more
doaj   +1 more source

Mapping River Bed Topography in Whitewater Rapids Using Bathymetric LiDAR

River Research and Applications, EarlyView.
ABSTRACT Bathymetric LiDAR captures river topography efficiently for clear and shallow water, but for mountain rivers, whitewater rapids still pose challenges. This study proposes a novel method to enable the extraction of bottom returns specifically in turbulent whitewater sections.
Jan Rhomberg‐Kauert, Theresa Himmelsbach, Florian Pöppl, Lucas Dammert, Martin Pfennigbauer, Gottfried Mandlburger   +5 more
wiley   +1 more source

Investigation of Moment and Damping Characteristics of Rotor Airfoil Dynamic Stall Under Unsteady‑Freestream

Nanjing Hangkong Hangtian Daxue Xuebao
Dynamic stall significantly limits the flight performance of helicopters. To reveal the mechanism behind the variations in aerodynamic moments and damping characteristics under unsteady freestream， a numerical simulation method for the unsteady flow ...
GAO Yuan, ZHAO Guoqing, JING Simeng, ZHAO Qijun, LU Fan   +4 more
doaj   +1 more source

A contribution to vision-based autonomous helicopter flight in urban environments [PDF]

, 2005
A navigation strategy that exploits the optic flow and inertial information to continuously avoid collisions with both lateral and frontal obstacles has been used to control a simulated helicopter flying autonomously in a textured urban environment ...
Anadan, Arkin, Barron, Barrows, Brooks, Camus, Camus, Cobos, Collett, Duchon, Duchon, Duchon, Duchon, Filliat, Fleet, Franceschini, Franceschini, Gibson, Gibson, Horn, Lee, Lee, Lee, Lucas, Meyer, Mura, Muratet, Netter, Neumann, Reiser, Srinivasan, Srinivasan, Srinivasan, Viollet   +33 more
core   +4 more sources

Ground‐truthing of satellite imagery to assess seabird colony size: A test using Adélie penguins

Remote Sensing in Ecology and Conservation, EarlyView.
Adélie penguin colony size can be estimated from space using very high‐resolution (VHR; 0.3–0.6 m resolution) satellite imagery due to the contrast between their guano stain and the surrounding terrain. Our study assessed the utility of VHR imagery for making indirect assessments of changes in colony size.
Alexandra J. Strang, Dean P. Anderson, Esme Robinson, Grant Ballard, Annie E. Schmidt, David G. Ainley, Kerry Barton, Fiona Shanhun, Elissa Z. Cameron, Michelle A. LaRue   +9 more
wiley   +1 more source