Artykuły w czasopismach na temat „Hovering platform”
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Bak, Jeongae, Jong-Won Kim, Sangrok Jin, Jongwon Kim i TaeWon Seo. "Hovering Performance Improvement by Modifying COG of Underwater Robotic Platform". Journal of the Korean Society for Precision Engineering 32, nr 7 (1.07.2015): 661–66. http://dx.doi.org/10.7736/kspe.2015.32.7.661.
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Aksenov, Alexey Y., Sergey V. Kuleshov i Alexandra A. Zaytseva. "An Application of Computer Vision Systems to Solve the Problem of Unmanned Aerial Vehicle Control". Transport and Telecommunication Journal 15, nr 3 (1.09.2014): 209–14. http://dx.doi.org/10.2478/ttj-2014-0018.
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Abstract The paper considers an approach for application of computer vision systems to solve the problem of unmanned aerial vehicle control. The processing of images obtained through onboard camera is required for absolute positioning of aerial platform (automatic landing and take-off, hovering etc.) used image processing on-board camera. The proposed method combines the advantages of existing systems and gives the ability to perform hovering over a given point, the exact take-off and landing. The limitations of implemented methods are determined and the algorithm is proposed to combine them in order to improve the efficiency.
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Zhou, Xiangcong, Xiaogang Song, Deyuan Zhang i Yanqiang Liu. "Bionic Hovering Micro-Aerial Vehicle Using Array-Spiracle Wings". Machines 10, nr 11 (2.11.2022): 1016. http://dx.doi.org/10.3390/machines10111016.
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Hovering ability is the basis of fixed-point monitoring and tracking of an aircraft. Herein, we propose a new hovering vehicle inspired by bird feathers, with an airfoil composed of passive opening and closing feather units. Two wings of the prototype are vertically distributed and driven in anti-phase linear reciprocation. The lift is generated by the asymmetric flow of air caused by the opening and closing of the feather unit. The design of the vehicle is simple and can be incorporated into a large-area hovering platform for large loads. In this paper, the design and fabrication of the vehicle are described, along with an aerodynamic theoretical model of the vehicle kinematics. The correctness of the model was verified by numerical calculations and tests on the opening and closing characteristics of the plume unit. The opening and closing characteristics of the feather unit were investigated and revealed through controlled-variable experiments. An experimental prototype with a mass of 52 g was built. During preliminary flight tests, the vibration frequency was controlled to verify that the prototype was capable of hovering and vertical takeoff and landing.
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KHO, I. Eng, Ahmad Windardi ALIYAZIS i Maulahikmah GALINIUM. "FRONT-END APPLICATION FOR MULTIPLE STOREFRONTS ECOMMERCE USING CROSS-PLATFORM TECHNOLOGY". BUSINESS EXCELLENCE AND MANAGEMENT 12, nr 1 (15.03.2022): 93–104. http://dx.doi.org/10.24818/beman/2022.12.1-07.
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Cross-platform framework is becoming more and more popular. Many giant tech companies have their own offering with different programming languages. With so many choices, sometimes it is difficult for a start-up developer to choose which framework they will use for their project. Therefore, this research aims to give insight for start-up developers on which cross-platform framework is better between Flutter and React Native by comparing their performance. This research achieved its goal by creating two identical mobile applications using Flutter and React Native and then comparing their performance using a theoretical framework that measures load time, average frame rate, and memory usage. The result of this testing is that Flutter has a shorter load time at 1.69 second compared to React Native at 4.26 second and lower memory usage at 6.52MB compared to React Native at 27.6MB. Their average frame rate is very comparable hovering around 60 frames per second. With faster load time and lower memory usage Flutter has better performance wise compared to React Native.
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Jing, Yu, Fugui Qi, Fang Yang, Yusen Cao, Mingming Zhu, Zhao Li, Tao Lei, Juanjuan Xia, Jianqi Wang i Guohua Lu. "Respiration Detection of Ground Injured Human Target Using UWB Radar Mounted on a Hovering UAV". Drones 6, nr 9 (3.09.2022): 235. http://dx.doi.org/10.3390/drones6090235.
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As an important and basic platform for remote life sensing, unmanned aerial vehicles (UAVs) may hide the vital signals of an injured human due to their own motion. In this work, a novel method to remove the platform motion and accurately extract human respiration is proposed. We utilized a hovering UAV as the platform of ultra-wideband (UWB) radar to capture human respiration. To remove interference from the moving UAV platform, we used the delay calculated by the correlation between each frame of UWB radar data in order to compensate for the range migration. Then, the echo signals from the human target were extracted as the observed multiple range channel signals. Owing to meeting the independent component analysis (ICA), we adopted ICA to estimate the signal of respiration. The results of respiration detection experiments conducted in two different outdoor scenarios show that our proposed method could accurately separate respiration of a ground human target without any additional sensor and prior knowledge; this physiological information will be essential for search and rescue (SAR) missions.
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Han, Jie, Weitao Jiang, Hongjian Zhang, Biao Lei, Lanlan Wang i Hongzhong Liu. "Submersible Soft‐Robotic Platform for Noise‐Free Hovering Utilizing Liquid–Vapor Phase Transition". Advanced Intelligent Systems 3, nr 1 (styczeń 2021): 2170013. http://dx.doi.org/10.1002/aisy.202170013.
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Jatsun, S., O. Emelyanova, B. Lushnikov, A. S. Martinez Leon, L. M. Mosquera Morocho, A. Pechurin i C. A. Nolivos Sarmiento. "Hovering control algorithm validation for a mobile platform using an experimental test bench". IOP Conference Series: Materials Science and Engineering 1027 (12.01.2021): 012008. http://dx.doi.org/10.1088/1757-899x/1027/1/012008.
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Chen, Kun, Zhiwei Shi, Shengxiang Tong, Yizhang Dong i Jie Chen. "Aerodynamic interference test of quad tilt rotor aircraft in wind tunnel". Proceedings of the Institution of Mechanical Engineers, Part G: Journal of Aerospace Engineering 233, nr 15 (29.05.2019): 5553–66. http://dx.doi.org/10.1177/0954410019852827.
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There is an obvious aerodynamic interference problem that occurs for a quad tilt rotor in near-ground hovering or in the conversion operating condition. This paper presents an aerodynamic interference test of the quad tilt rotor in a wind tunnel. A 1:35 scale model of the quad tilt rotor is used in this test. To substitute for the ground, a moveable platform is designed in a low-speed open-loop wind tunnel to simulate different flight altitudes of the quad tilt rotor in hovering or forward flight. A rod six-component force balance is used to measure the loads on the aircraft, and the flow field below the airframe is captured using particle image velocimetry. The experimental results show that the ground effect is significant when the hover height above the ground is less than the rotor diameter of the quad tilt rotor aircraft, and the maximum upload of the airframe is approximately 12% of the total vertical thrust with the appearance of obvious fountain flow. During the conversion operating condition, the upload of the airframe is reduced compared with that in the hovering state, which is affected by rotor wake and incoming flow. The aerodynamic interference test results of the quad tilt rotor aircraft have important reference value in power system selection, control system design, and carrying capacity improvement with the advantage of ground effect.
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Wang, Shengye, Haitao Wang, Wei Xiong i Guangfeng Guan. "Vibration Control of a Helicopter Rescue Simulator on a Flexible Base". Computational Intelligence and Neuroscience 2022 (25.04.2022): 1–10. http://dx.doi.org/10.1155/2022/7173421.
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The vibration compensation control of a hovering helicopter rescue simulator mounted on a crane beam is studied in this research. A Stewart platform is used as the motion generator of the helicopter simulation cabin and the vibration compensation device of the beam, simultaneously. This study describes how the dynamic model of the Stewart platform with consideration of the beam vibration is established. To determine the interference of the Stewart platform motion control in the special application of a large component flexible base requiring large-scale movement, a hybrid vibration controller composed of a feed-forward compensation module and a PD (proportional-derivative) feedback control module is designed. The experimental results show that this method can effectively compensate for the beam vibration and improve the accuracy of the motion reproduction of a helicopter simulation cabin.
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Wang, Shengye, Haitao Wang, Wei Xiong i Guangfeng Guan. "Vibration Control of a Helicopter Rescue Simulator on a Flexible Base". Computational Intelligence and Neuroscience 2022 (25.04.2022): 1–10. http://dx.doi.org/10.1155/2022/7173421.
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The vibration compensation control of a hovering helicopter rescue simulator mounted on a crane beam is studied in this research. A Stewart platform is used as the motion generator of the helicopter simulation cabin and the vibration compensation device of the beam, simultaneously. This study describes how the dynamic model of the Stewart platform with consideration of the beam vibration is established. To determine the interference of the Stewart platform motion control in the special application of a large component flexible base requiring large-scale movement, a hybrid vibration controller composed of a feed-forward compensation module and a PD (proportional-derivative) feedback control module is designed. The experimental results show that this method can effectively compensate for the beam vibration and improve the accuracy of the motion reproduction of a helicopter simulation cabin.
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Li, Shaobao, Petar Durdevic i Zhenyu Yang. "Hovering Control for Automatic Landing Operation of An Inspection Drone to A Mobile Platform". IFAC-PapersOnLine 51, nr 8 (2018): 245–50. http://dx.doi.org/10.1016/j.ifacol.2018.06.384.
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IONITA, Achim, Andrei LUNGOCI i Ion TOMESCU. "Quad Performances and Manoeuvrability of TWQH platf". INCAS BULLETIN 14, nr 4 (2.12.2022): 63–78. http://dx.doi.org/10.13111/2066-8201.2022.14.4.6.
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Accurate dynamic modelling of the Tandem Wing Quadcopter Hybrid (TWQH) platform is becoming increasingly important, as strict requirements are progressively being imposed on the UAV (unmanned aerial vehicles) control system in the transition phase from vertical to level flight and vice versa. This work aims to present preliminary design performances in the steady and manoeuvring flight of the platform thrusted by only four rotors directed upward. The aerodynamic effects of tandem wings make a significant contribution to the evaluation of performance, controllability and manoeuvrability in hovering and low speed phase. More specifically, steady, level, symmetrical pull-up and coordinated turns approaches of the quad model are considered and the results obtained in the simulation study are presented and discussed.
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M, Sundar, Ashok Kuppusamy i Kugharaja V. "Development of Airframe for Unmanned VTOL Flying Platform". ECS Transactions 107, nr 1 (24.04.2022): 1585–95. http://dx.doi.org/10.1149/10701.1585ecst.
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A challenging issue associated with fixed wing Unmanned Aerial Vehicles (UAVs) is that these vehicles are often not appropriate for operating effectively in limited airspace. This problem emerges especially in urban environment where the usage of a runway is not possible, and UAVs usually have to fly at a relatively low speed and altitude. The development of a vertical take-off and landing (VTOL) fixed-wing plane is a promising trend which hopefully will solve this issue. This project aims to address difficulties relating to reconnaissance and surveillance for military and civilian applications. The design concept simplifies tilt-rotor systems by using only the control fins to shift from horizontal to vertical flight and vice-versa, allowing the motor/rotor elements to be fixed. All the basic maneuvering of the aircraft is handled by the control surfaces of the airframe. The system consists of one wing with two motors and two elevons creating a tractor configuration airframe. The active flow over the surfaces assists in VTOL and allows the aircraft to seamlessly carry out vertical flight, such as hovering, and offer maneuverability at slow speeds during horizontal flight.
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Low, Jun En, Danial Sufiyan, Luke Soe Thura Win, Gim Song Soh i Shaohui Foong. "Design of a Hybrid Aerial Robot with Multi-Mode Structural Efficiency and Optimized Mid-Air Transition". Unmanned Systems 07, nr 04 (17.09.2019): 195–213. http://dx.doi.org/10.1142/s2301385019500067.
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In this paper, we explore a novel multi-mode hybrid Unmanned Aerial Vehicle (UAV). We combine a tailless fixed-wing with a dual-wing monocopter such that the craft’s propulsion systems and aerodynamic surfaces are fully utilized in both a horizontal cruising mode and a vertical hovering mode. This maximizes the structural efficiency across the flight envelope, thereby reducing drag and unused mass while airborne in either flight mode. This UAV is also designed such that the transition between the two flight modes can be executed in mid-air, using only its existing flight actuators and sensors — there are no transition specific actuators. Using two prototypes, the foundational design and control of the system is established; the first explores the hovering mode characteristics of the unique dual-wing monocopter configuration, while the second explores the full multi-mode capabilities of the combined platform. In addition to analytical simulations, the prototypes are experimentally evaluated and assessed to demonstrate the feasibility, viability and potential of this multi-mode aerial robot design.
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Chen, Xi, Fu Yang Chen i Bin Jiang. "Study on Fault-Tolerant Control Scheme for a Helicopter via Adaptive H∞ Control". Applied Mechanics and Materials 455 (listopad 2013): 395–401. http://dx.doi.org/10.4028/www.scientific.net/amm.455.395.
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In this paper, the stabilization problem for the 3 Degree of Freedom (3-DOF) hovering system of Quadrotor with actuator faults is investigated. To handle the helicopter system, an H robust fault-tolerant state feedback control is proposed. In addition, an adaptive method is combined with fault-tolerant H control to improve the flight performance. A more practical actuator fault is built, and the model of the system is presented. The design operates in Linear Matrix Inequality (LMI) technique. Finally, the design was verified on both MATLAB and 3-DOF platform to exam the feasibility and stability of the method.
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Nishida, Yuya, Takashi Sonoda, Shinsuke Yasukawa, Kazunori Nagano, Mamoru Minami, Kazuo Ishii i Tamaki Ura. "Underwater Platform for Intelligent Robotics and its Application in Two Visual Tracking Systems". Journal of Robotics and Mechatronics 30, nr 2 (20.04.2018): 238–47. http://dx.doi.org/10.20965/jrm.2018.p0238.
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A hovering-type autonomous underwater vehicle (AUV) capable of cruising at low altitudes and observing the seafloor using only mounted sensors and payloads was developed for sea-creature survey. The AUV has a local area network (LAN) interface for an additional payload that can acquire navigation data from the AUV and transmit the target value to the AUV. In the handling process of the state flow of an AUV, additional payloads can control the AUV position using the transmitted target value without checking the AUV condition. In the handling process of the state flow of an AUV, additional payloads can control the AUV position using the transmitted target value without checking the AUV condition. In this research, water tank tests and sea trials were performed using an AUV equipped with a visual tracking system developed in other laboratories. The experimental results proved that additional payload can control the AUV position with a standard deviation of 0.1 m.
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Wiegman, Christopher R., Ramarao Venkatesh i Scott A. Shearer. "Intra-Canopy Sensing Using Multi-Rotor sUAS: A New Approach for Crop Stress Detection and Diagnosis". Journal of the ASABE 65, nr 4 (2022): 913–25. http://dx.doi.org/10.13031/ja.14342.
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HighlightsA novel platform was developed for intra-canopy insertion of sensors from a multi-rotor sUAS.The system enables real-time data acquisition from inside the crop canopy comparable to an in-person view.The system provides ideal data for use in modern CNN-based stress diagnosis in row crop production.Abstract. Remote sensing is a critical tool in precision agriculture, giving producers the ability to monitor field conditions throughout the growing season. Although several remote sensing platforms are in use today, small unmanned aerial systems (sUAS) provide the greatest flexibility with the highest resolution. As sUAS capabilities continue to increase (i.e., payload, flight time, and speed), their potential in commercial row crop production is substantial. However, like other forms of remote sensing, traditional sUAS are limited to a nadir view of the target and only capture the top of the crop canopy. Although disease epidemiology and stress origins vary, this limited view usually does not capture the impact of stress at the initial manifestation. For example, stresses such as macronutrient deficiencies in corn originate at the base of the plant and then move upward as nutrients translocate. By the time the stress is detectable at the top of the canopy, the opportunity to mitigate yield loss is limited. A new sUAS platform is needed for sensing beneath the upper portion of the canopy. The Stinger platform, developed to meet this need, consists of a 4.0 m fiberglass rod, custom sensor mount, communication network, and radio link. Using this platform, a variety of sensors can be inserted into the crop canopy from a hovering sUAS. The Stinger platform, when combined with artificial intelligence (AI), significantly expands the capabilities of sUAS for diagnosis of crop stress in row crop production. Keywords: Intra-canopy sensing, Remote sensing, RGB imagery, Stress diagnosis, sUAS.
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Wang, Wei, Yu Ze Song, Kenzo Nonami, Yong Cheng, Yong Zhou i Feng Wang. "Attitude Controller Design for a Six-Rotor Type MAV". Key Engineering Materials 480-481 (czerwiec 2011): 1155–60. http://dx.doi.org/10.4028/www.scientific.net/kem.480-481.1155.
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MAV (Micro Air Vehicle) can be used for many applications such as the investigation of inhospitable environments, regions contaminated by nuclear pollution or hazardous material and other inaccessible areas. For such kind of purposes, a small machine that can autonomously fly seems to be appropriate. Our MAV research group selects a Quad-Rotor MAV as our platform, and achieved automated take-off, landing, hovering, way-point navigation, vision-based navigation flight. However, the payload of our current platform is low (about 500grams), and the flight duration is only about 10 minutes. To overcome these obstacles, we designed a Six-Rotor type MAV with 770mm of diameter, 1.9Kg of weight, 1.5Kg of payload and 12 minutes of flight duration (without payload). In this paper, we present the main design considerations which are essential for the construction of Six-Rotor type MAV and attitude controller design technique.
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Sato, Ryohei, Kento Tanaka, Hanako Ishida, Saki Koguchi, Jane Pauline Ramos Ramirez, Haruka Matsukura i Hiroshi Ishida. "Detection of Gas Drifting Near the Ground by Drone Hovering Over: Using Airflow Generated by Two Connected Quadcopters". Sensors 20, nr 5 (4.03.2020): 1397. http://dx.doi.org/10.3390/s20051397.
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This paper describes the utilization of the downwashes of multicopters for gas-sensing applications. Multirotor drones are an attractive platform for sensing applications. Their high maneuverability enables swift scanning of a target area with onboard sensors. When equipped with a gas sensor and used for gas-sensing applications, however, the strong downwash produced by the rotors poses a problem. When a multicopter is hovering at a low altitude, gas puffs leaked from a gas source on the ground are all blown away. Here, we propose to use two multicopters connected by a rod or a string and place a gas sensor at the midpoint of the rod/string. The downwash generated by each multicopter spreads radially after it impinges on the ground. When two multicopters are connected, the airflows spreading radially along the ground from the two multicopters impinge at the center and are deflected in the upward direction. Gas puffs wafting near the ground surface between the two multicopters are carried by this upward airflow to the gas sensor. Experimental results are presented to show the soundness of the proposed method. The connected quadcopters hovering over an ethanol gas source was able to detect the gas even with a moderate cross-flow.
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Khizer, Arbab Nighat, Dai Yaping, Syed Amjad Ali i Xu Xiangyang. "Stable Hovering Flight for a Small Unmanned Helicopter Using Fuzzy Control". Mathematical Problems in Engineering 2014 (2014): 1–17. http://dx.doi.org/10.1155/2014/208253.
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Stable hover flight control for small unmanned helicopter under light air turbulent environment is presented. Intelligent fuzzy logic is chosen because it is a nonlinear control technique based on expert knowledge and is capable of handling sensor created noise and contradictory inputs commonly encountered in flight control. The fuzzy nonlinear control utilizes these distinct qualities for attitude, height, and position control. These multiple controls are developed using two-loop control structure by first designing an inner-loop controller for attitude angles and height and then by establishing outer-loop controller for helicopter position. The nonlinear small unmanned helicopter model used comes from X-Plane simulator. A simulation platform consisting of MATLAB/Simulink and X-Plane©flight simulator was introduced to implement the proposed controls. The main objective of this research is to design computationally intelligent control laws for hovering and to test and analyze this autopilot for small unmanned helicopter model on X-Plane under ideal and mild turbulent condition. Proposed fuzzy flight controls are validated using an X-Plane helicopter model before being embedded on actual helicopter. To show the effectiveness of the proposed fuzzy control method and its ability to cope with the external uncertainties, results are compared with a classical PD controller. Simulated results show that two-loop fuzzy controllers have a good ability to establish stable hovering for a class of unmanned rotorcraft in the presence of light turbulent environment.
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Chan, Woei Leong, Muhammad Azli Bin Jaffar i Quoc Viet Nguyen. "Preliminary Study on Stability of a Hovering Bi-flap Flapping Wing Platform using Cycle-Averaged Linear Models". Journal of Instrumentation, Automation and Systems 1, nr 3 (8.01.2016): 84–90. http://dx.doi.org/10.21535/jias.v1i3.168.
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Wang, Lu, i Ronald W. Yeung. "Investigation of full and partial ground effects on a flapping foil hovering above a finite-sized platform". Physics of Fluids 28, nr 7 (lipiec 2016): 071902. http://dx.doi.org/10.1063/1.4954656.
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Kafafy, Raed, Mohamed Okasha, Shamma Alblooshi, Hessa Almansoori, Salma Alkaabi, Salma Alshamsi i Turfa Alkaabi. "A remotely-controlled micro airship for wireless coverage". Applied Research and Smart Technology (ARSTech) 3, nr 2 (27.12.2022): 72–80. http://dx.doi.org/10.23917/arstech.v3i2.1190.
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This paper describes the design process and prototype development of a remotely controlled airship for wireless coverage. The airship is designed to be used as a platform to provide wireless coverage for rural areas. The design process follows a systematic design process for lighter-than-air vehicles, modified to impart slight heaviness to the vehicle. A remotely-controlled, thrust-vectored electric propulsion system offsets the slight vehicle heaviness. The electric propulsion system comprises two tilting rotors for takeoff, cruise, hovering, and horizontal manoeuvring. A rudder-less, rotor-less, cruciform fin design was implemented. A reduced-scale prototype of the airship was developed to prove the design concept. The airship prototype was successfully tested in an indoor environment.
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Du, Peizhou, S. H. Huang, Wencheng Yang, Yingqiang Wang, Zhikun Wang, Ruoyu Hu i Ying Chen. "Design of a Disc-Shaped Autonomous Underwater Helicopter with Stable Fins". Journal of Marine Science and Engineering 10, nr 1 (5.01.2022): 67. http://dx.doi.org/10.3390/jmse10010067.
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The autonomous underwater helicopter, shortly referred to as AUH, is a newly developed underwater platform with a unique disc shape. An autonomous underwater helicopter with a suboptimal disc shape is presented in this paper. It adopts a multirotor configuration and stable fins to overcome the shape shortcoming for motion stabilization. Its motion analysis and mathematical model have been introduced accordingly. Computational Fluid Dynamics (CFD) simulation is carried out to evaluate fins’ hydrodynamic performance. Proportional integral derivative (PID) and sliding mode fuzzy (SMF) control are adopted for controller design. Finally, the controller is applied on this AUH and extensively tested in various simulations and experiments, and the results illustrate the high stabilization and robustness of the controller and the hovering stability and manoeuvrability of AUH.
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Khalesi, Mohammad Hossein, Hassan Salarieh i Mahmoud Saadat Foumani. "System identification and robust attitude control of an unmanned helicopter using novel low-cost flight control system". Proceedings of the Institution of Mechanical Engineers, Part I: Journal of Systems and Control Engineering 234, nr 5 (27.08.2019): 634–45. http://dx.doi.org/10.1177/0959651819869718.
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In recent years, unmanned aerial systems have attracted great attention due to the electronic systems technology advancements. Among these vehicles, unmanned helicopters are more important because of their special abilities and superior performance. The complex nonlinear dynamic system (caused by main rotor flapping dynamics coupled with the rigid body rotational motion) and considerable effects of ambient disturbance make their utilization hard in actual missions. Attitude dynamics have the main role in helicopter stabilization, so implementing proper control system for attitude is an important issue for unmanned helicopter hovering and trajectory tracking performance. Besides this, experimental utilization of low-cost flight control system for unmanned helicopters is still a challenging task. In this article, dynamic modeling, system identification, and robust control system implementation of roll and pitch dynamics of an unmanned helicopter is performed. A TRex-600E radio-controlled helicopter is equipped with a novel low-cost flight control system designed and constructed based on Raspberry Pi Linux-based microcomputer. Using Raspberry Pi makes this platform simpler to utilize and more time and cost-effective than similar platforms used before. The experiments are performed on a 5-degree-of-freedom testbed. The robust control system is designed based on [Formula: see text] method and is evaluated in real flight tests. The experiment results show that the proposed platform has the ability to successfully control the roll and pitch dynamics of the unmanned helicopter.
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Tsui, Amy B. M., Carol K. K. Chan, Gary Harfitt i Promail Leung. "Crisis and opportunity in teacher preparation in the pandemic: exploring the “adjacent possible”". Journal of Professional Capital and Community 5, nr 3/4 (13.07.2020): 237–45. http://dx.doi.org/10.1108/jpcc-07-2020-0061.
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PurposeThis paper draws on Kauffman's theory of the “adjacent possible” to make sense of the practices which have emerged in response to school and university closures in Hong Kong and reflects on what opportunities exist in this current global crisis.Design/methodology/approachThis paper drew on qualitative data from two emergent practices – the e-practicum and co-teaching on an online platform – in a teacher preparation program at the University of Hong Kong. The data set included online teaching resources produced by student teachers (STs), reflections from STs, feedback from mentors and university tutors, interactions on an online platform and interviews with co-teaching team members.FindingsThe authors found “emergent practices” were developed in response to the pandemic by pushing the boundaries of existing practices and exploring the opportunities hovering at the edges of the possible. These practices were still evolving, but they contained elements that can morph into innovative practices in teacher preparation.Originality/valueThis paper provides a perspective on where opportunity in a crisis can be found and what innovation means in an educational context.
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De Martini, Daniele, Giuseppe Valerio Gramazio, Alessandro Bertini, Carlo Rottenbacher i Tullio Facchinetti. "Design and Modeling of a Quadcopter with Double Axis Tilting Rotors". Unmanned Systems 05, nr 03 (lipiec 2017): 169–80. http://dx.doi.org/10.1142/s2301385017400040.
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Multirotors are well suited for application tasks such as surveillance and exploration of otherwise inaccessible areas. Standard quadrotors have limitations in their possible configurations due to their underactuation. For this reason, some spatial configurations are not possible, such as hovering while maintaining a nonhorizontal orientation. This paper presents an overactuated quadrotor platform with double axes tilting propellers. The peculiarity of the proposed platform is that, beside the usual control on the four propellers, it allows to tilt each arm where motors are mounted along two independent axis. The resulting number of control inputs is 12, allowing a higher number of stable configurations with respect to traditional quadrotors. As a result, it can assume spatial orientations that are not possible for traditional quadcopters, enabling the possibility to deal with obstacles that would generally impede the motion of normal quadcopters. This feature allows to potentially explore a larger space. This paper presents the design and modeling of the quadrotor. Numerical simulations are carried out to show the effectiveness of the proposed solution.
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Zou, Jie Tong, Guan Wei Huang i Chieh Yueh Hsu. "The Design and Implementation of Hexa-Rotor Aerial Robot". Applied Mechanics and Materials 300-301 (luty 2013): 357–61. http://dx.doi.org/10.4028/www.scientific.net/amm.300-301.357.
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Today, when the robot technology is booming, various sensors and intelligent functions that applied in robots can be transferred and applied to the unmanned aerial robot. It will make the unmanned aerial robot not an ordinary UAV any longer, but an intelligent robot that can fly. Conventional UAVs are not well suited for use in confined spaces, such as small passageways or indoor halls, e.t.c. The multi-rotor copters have the vertical take-off and landing (VTOL) ability for indoor flight. The most popular research topics for multi-rotor copters are Quad- copter and Hexa-copter. The objective of this research is to design and build a hexa-rotor aerial robot. We used AVR microcontroller as the flight control system, and use three-axis gyroscope and three-axis accelerometer for attitude sensing of the aerial robot; the flight altitude is estimated with barometric altimeter; the closed loop control of the aerial robot is carried out with PID control to meet the requirements, such as self-balancing, hovering and etc. Multi-sensors had been applied to the hexa-rotor aerial robot, and verified the feasibility with experiments. A universal test platform was designed to test the stability and balance of the Hexa-rotor aerial robot. An external force was applied on the aerial robot from pitch, roll and yaw direction, the aerial robot can return to self-balancing flight quickly. Finally, the hexa-rotor aerial robot can make a stable hovering during the outdoor test fly.
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Li, J. M., C. R. Li, G. Z. Su, W. Li, L. L. Ma i Y. K. Liu. "MAPPING SYSTEM AND PHOTOGRAMMETRIC PROCESSING METHOD FOR TETHERED BALLOON PLATFORM". ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLII-2/W16 (17.09.2019): 157–61. http://dx.doi.org/10.5194/isprs-archives-xlii-2-w16-157-2019.
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<p><strong>Abstract.</strong> As a platform with the advantages of safety, wide altitude range and long flight time, tethered balloon has been used in archaeology, coastal, island mapping and other related fields. Tethered balloon is tied to the mooring system by tether rope, and often moves in a small range with the airflow, resulting in a very close distance between the camera stations. Due to the small base-to-height ratio, failure of relative orientation or poor quality of point cloud tend to appear frequently. In this paper, a mapping system for tethered balloon is introduced which consists of a wide-angle camera, two auxiliary orientation cameras, and a dual GNSS/IMU system. The wide-angle camera combined by five cameras provides a larger observation range. Two auxiliary orientation cameras installed at the end of extension rods are designed to increase the baseline. The system should be operated during the taking-off, hovering and landing stages of the tethered balloon, so as to take images of different altitudes. The system has been adopted in the first experimental flight in 2018 to perform island topographic survey. Data processing method was applied to test the effect of the system. The method that choosing wide-angle images of different heights, and auxiliary images at low-altitude can be used for aerial triangulation successfully, and obtain point cloud with good quality. The results showed that by adding auxiliary cameras and taking images of different heights for data processing, the problem of small intersection angle could be overcome to some extent.</p>
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Choi, Jae-Weon, Tae-Kyu Ha, Eko Henfri Binugroho, Chang-Ho Yu i Young-Bong Seo. "Design of a Test bed and Performance Evaluation for a Hovering Type Autonomous Underwater Vehicle under Open Control Platform". Journal of Institute of Control, Robotics and Systems 16, nr 5 (1.05.2010): 489–97. http://dx.doi.org/10.5302/j.icros.2010.16.5.489.
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Jin, Sangrok, Jihoon Kim, Jongwon Kim i TaeWon Seo. "Six-Degree-of-Freedom Hovering Control of an Underwater Robotic Platform With Four Tilting Thrusters via Selective Switching Control". IEEE/ASME Transactions on Mechatronics 20, nr 5 (październik 2015): 2370–78. http://dx.doi.org/10.1109/tmech.2014.2378286.
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Çakıcı, Ferit, i M. Kemal Leblebicioğlu. "Modeling and simulation of a small-sized Tiltrotor UAV". Journal of Defense Modeling and Simulation: Applications, Methodology, Technology 9, nr 4 (4.07.2011): 335–45. http://dx.doi.org/10.1177/1548512911414951.
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Unmanned aerial vehicles (UAVs) are remotely piloted or self-piloted aircrafts that can carry cameras, sensors, communication equipment and other payloads. Tiltrotor UAVs provide a unique platform that fulfills the needs for ever-changing mission requirements, by combining the desired features of hovering like a helicopter and reaching high forward speeds like an airplane, which might be a force multiplier in the battlefield. In this paper, the conceptual design and aerodynamical model of a realizable small-sized Tiltrotor UAV are presented, and the linearized state-space models are obtained around the trim points for airplane, helicopter and conversion modes. Controllers are designed using tracking optimal control method and gain scheduling is employed to obtain a simulation for the whole flight envelope. An interactive software infrastructure is established for the design, analysis and simulation phases, based on the theoretical concepts.
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Lin, Feng, Kevin Z. Y. Ang, Fei Wang, Ben M. Chen, Tong H. Lee, Beiqing Yang, Miaobo Dong i in. "Development of an Unmanned Coaxial Rotorcraft for the DARPA UAVForge Challenge". Unmanned Systems 01, nr 02 (październik 2013): 211–45. http://dx.doi.org/10.1142/s2301385013400049.
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In this paper, we present a comprehensive design for a fully functional unmanned rotorcraft system: GremLion. GremLion is a new small-scale unmanned aerial vehicle (UAV) concept using two contra-rotating rotors and one cyclic swash-plate. It can fit within a rucksack and be easily carried by a single person. GremLion is developed with all necessary avionics and a ground control station. It has been employed to participate in the 2012 UAVForge competition. The proposed design of GremLion consists of hardware construction, software development, dynamics modeling and flight control design, as well as mission algorithm investigation. A novel computer-aided technique is presented to optimize the hardware construction of GremLion to realize robust and efficient flight behavior. Based on the above hardware platform, a real-time flight control software and a ground control station (GCS) software have been developed to achieve the onboard processing capability and the ground monitoring capability respectively. A GremLion mathematical model has been derived for hover and near hover flight conditions and identified from experimental data collected in flight tests. We have combined H∞ technique, a robust and perfect tracking (RPT) approach, and custom-defined flight scheduling to design a comprehensive nonlinear flight control law for GremLion and successfully realized the automatic control which includes take-off, hovering, and a variety of essential flight motions. In addition, advanced mission algorithms have been presented in the paper, including obstacle detection and avoidance, as well as target following. Both ground and flight experiments of the complete system have been conducted including autonomous hovering, waypoint flight, etc. The test results have been presented in this paper to verify the proposed design methodology.
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Ramli, Hanif, Wahyu Kuntjoro i Ahmad Khushairy Makhtar. "Advanced Autonomous Multirotor Response System". Applied Mechanics and Materials 393 (wrzesień 2013): 299–304. http://dx.doi.org/10.4028/www.scientific.net/amm.393.299.
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Autonomous Unmanned Aerial Vehicle (UAV) in the form of multi-rotor system is having a great potential in various applications such as disaster management (as first response system) and surveillance. It is known that conventional helicopter system, capable of hovering, is practical and reliable as many applications have confirmed its capabilities. However it is only achievable once highly optimized control architecture is realized. The objective of the research presented in this paper is, to develop a small multi rotor UAV system that is able to autonomously flying from one way point to another in a stable manner. This small UAV is termed as Mini (or Micro) Aerial Vehicle (MAV). In this project, a four-rotor system was developed, and becoming the platform of various sensors system, flight control system, and electric propulsion system. The MAV was programmed to be able to lift off and fly to waypoints making use of GPS. This paper presents the architecture of the MAV and its autonomous flight.
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Basiri, Amin, Valerio Mariani, Giuseppe Silano, Muhammad Aatif, Luigi Iannelli i Luigi Glielmo. "A survey on the application of path-planning algorithms for multi-rotor UAVs in precision agriculture". Journal of Navigation 75, nr 2 (13.01.2022): 364–83. http://dx.doi.org/10.1017/s0373463321000825.
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AbstractMulti-rotor Unmanned Aerial Vehicles (UAVs), although originally designed and developed for defence and military purposes, in the last ten years have gained momentum, especially for civilian applications, such as search and rescue, surveying and mapping, and agricultural crops and monitoring. Thanks to their hovering and Vertical Take-Off and Landing (VTOL) capabilities and the capacity to carry out tasks with complete autonomy, they are now a standard platform for both research and industrial uses. However, while the flight control architecture is well established in the literature, there are still many challenges in designing autonomous guidance and navigation systems to make the UAV able to work in constrained and cluttered environments or also indoors. Therefore, the main motivation of this work is to provide a comprehensive and exhaustive literature review on the numerous methods and approaches to address path-planning problems for multi-rotor UAVs. In particular, the inclusion of a review of the related research in the context of Precision Agriculture (PA) provides a unified and accessible presentation for researchers who are initiating their endeavours in this subject.
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Lei, Yao, Yuhui Huang i Hengda Wang. "Aerodynamic Performance of an Octorotor SUAV with Different Rotor Spacing in Hover". Processes 8, nr 11 (28.10.2020): 1364. http://dx.doi.org/10.3390/pr8111364.
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To study the aerodynamic performance of hovering octorotor small unmanned aerial vehicles (SUAV) with different rotor spacing, the computational fluid dynamics (CFD) method is applied to analyze the flow field of an octorotor SUAV in detail. In addition, an experimental platform is built to measure the thrust and power of the rotors with rotor spacing ratios L/D of 1.0, 1.2, 1.4, 1.6, and 1.8, sequentially. According to the theory of momentum, rotor aerodynamic performance is obtained with qualitative analysis. Further analysis with numerical simulation is presented with the flow field of the octorotor SUAV, the vorticity distribution, velocity distribution, pressure distribution, and streamline. The results show that the aerodynamic performance varies with the rotor spacing. Specifically, the aerodynamic performance is poor at L/D = 1.0, which is accompanied with strong interaction of wake and tip vortexes and interaction with each other. However, the aerodynamic efficiency is much improved with a larger rotor spacing, especially achieving the highest at L/D = 1.8, which is considered to be the best rotor spacing ratio for this kind of octorotor SUAV.
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Chen, Chen-Wei, Ying Chen i Qian-Wen Cai. "Hydrodynamic-Interaction Analysis of an Autonomous Underwater Hovering Vehicle and Ship with Wave Effects". Symmetry 11, nr 10 (29.09.2019): 1213. http://dx.doi.org/10.3390/sym11101213.
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A new vertical axis-symmetrical dish-shaped autonomous underwater vehicle (AUV) with excellent maneuverability, known as the autonomous underwater hovering vehicle (AUH), is proposed. This study investigates an important working model of the AUH approaching a host ship in waves. The working model of AUH–Ship interactions deals with hydrodynamic interaction, seakeeping performance for communication, launch, and recovery near a free surface. The AUH is able to navigate and implement homing automation through acoustic positioning equipment, a depth sensor, a heading compass, and a Doppler velocity log (DVL) in the working area based on numerical analysis of AUH–Ship hydrodynamic performance in this study. The hydrodynamic-interaction performance of the AUH and ship near free surfaces is analyzed in the frequency and time domains using a potential-based surface-panel method based on a commercial computational fluid dynamics (CFD) solver (ANSYS-AQWA), i.e., a 3D panel code of seakeeping performance module in the ANSYS platform where the fluid is assumed to be irrotational, inviscid, and incompressible. The motion performance of the AUH approaching the host ship, with a dynamic positioning system in waves, is studied by estimating interactive response-amplitude operators (RAOs) of the AUH and host ship in 6-DOF that were estimated and analyzed at different wave amplitudes and frequencies. In the ship and AUH interaction simulations, the host ship is assumed to be a well-posed station keeping in waves with zero service speed. The AUH and ship interference effect is studied at different distances to appropriate recovery and launch positions for the AUH at the following sea and beam sea, i.e., wave-encounter angles 0° and 90°, respectively. In addition, the hydrodynamic interaction of the AUH and ship in yaw and roll at different AUH velocities is estimated. The AUH motion performance approaching the ship in long-crested irregular seas is analyzed in the time domain using the Pierson–Moskowitz wave spectrum model. Viscid hydrodynamic force on AUH motion in roll near a free surface was significant. A damping model was adopted to formulate the viscid effect to enhance the effectiveness of the ANSYS-AQWA inviscid potential-based solver. Numerical analysis of motion RAO of the AUH in roll with the damping effect was compared to the experimental data in wave-frequency range 0.2–1.0 Hz, resulting in the average error being reduced from 21.03% to 9.95% to verify the method’s accuracy. The proposed method conveniently and accurately predicted hydrodynamic-interaction characteristics and motion RAO for a dish-type AUH and host ship for the precise use of mounted sensors in waves. The results of these simulations can be used to analyze the homing automation and adaptive controllability to advance the AUV development and design.
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Yokota, Yusuke, i Takumi Matsuda. "Underwater Communication Using UAVs to Realize High-Speed AUV Deployment". Remote Sensing 13, nr 20 (18.10.2021): 4173. http://dx.doi.org/10.3390/rs13204173.
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To monitor ocean and seafloor properties in detail, sensors are generally installed on autonomous underwater vehicles (AUVs). An AUV cannot accurately determine its absolute position and needs to communicate with a sea-surface vehicle. However, sea-surface vehicles cannot perform high-speed observations with high efficiency due to their low mobility and high labor and equipment costs, e.g., vessel charter charges, operator restraint time on the sea surface during observations, etc. From this perspective, unmanned aerial vehicles (UAVs) have potential as the next-generation communication platform. In this study, we conducted a demonstration experiment to use UAV as a sea-surface base for underwater communication with an AUV. We investigated the capability of a UAV to land on the sea surface, drift like a buoy to receive underwater data, and finally lift off to return to its base. The experimental results suggest that UAVs provide suitable communication performance for research near the shore in terms of robust hovering control, stability against sway, and operation speed. To carry out more complicated work (such as transportation) of UAVs, further research in areas such as weight reduction is required.
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Khusheef, Ahmed S. "An Efficient Approach for Modeling and Control of a Quadrotor". Wasit Journal of Engineering Sciences 4, nr 2 (2.11.2016): 1–16. http://dx.doi.org/10.31185/ejuow.vol4.iss2.44.
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A quadrotor is a four-rotor aircraft capable of vertical take-off and landing, hovering, forward flight, and having great maneuverability. Its platform can be made in a small size make it convenient for indoor applications as well as for outdoor uses. In model there are four input forces that are essentially the thrust provided by each propeller attached to each motor with a fixed angle. The quadrotor is basically considered an unstable system because of the aerodynamic effects; consequently, a close-loop control system is required to achieve stability and autonomy. Such system must enable the quadrotor to reach the desired attitude as fast as possible without any steady state error. In this paper, an optimal controller is designed based on a Proportional Integral Derivative (PID) control method to obtain stability in flying the quadrotor. The dynamic model of this vehicle will be also explained by using Euler-Newton method. The mechanical design was performed along with the design of the controlling algorithm. Matlab Simulink was used to test and analyze the performance of the proposed control strategy. The experimental results on the quadrotor demonstrated the effectiveness of the methodology used.
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Moran, Christopher J., Carl A. Seielstad, Matthew R. Cunningham, Valentijn Hoff, Russell A. Parsons, LLoyd Queen, Katie Sauerbrey i Tim Wallace. "Deriving Fire Behavior Metrics from UAS Imagery". Fire 2, nr 2 (22.06.2019): 36. http://dx.doi.org/10.3390/fire2020036.
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The emergence of affordable unmanned aerial systems (UAS) creates new opportunities to study fire behavior and ecosystem pattern—process relationships. A rotor-wing UAS hovering above a fire provides a static, scalable sensing platform that can characterize terrain, vegetation, and fire coincidently. Here, we present methods for collecting consistent time-series of fire rate of spread (RoS) and direction in complex fire behavior using UAS-borne NIR and Thermal IR cameras. We also develop a technique to determine appropriate analytical units to improve statistical analysis of fire-environment interactions. Using a hybrid temperature-gradient threshold approach with data from two prescribed fires in dry conifer forests, the methods characterize complex interactions of observed heading, flanking, and backing fires accurately. RoS ranged from 0–2.7 m/s. RoS distributions were all heavy-tailed and positively-skewed with area-weighted mean spread rates of 0.013–0.404 m/s. Predictably, the RoS was highest along the primary vectors of fire travel (heading fire) and lower along the flanks. Mean spread direction did not necessarily follow the predominant head fire direction. Spatial aggregation of RoS produced analytical units that averaged 3.1–35.4% of the original pixel count, highlighting the large amount of replicated data and the strong influence of spread rate on unit size.
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Daly, Robert Michael, Kevin Nicholas, Jessica Flynn, Katherine Panageas, Nicholas Silva, Elaine Duck, Alice Zervoudakis i in. "Association between remote monitoring and acute care visits in high-risk patients initiating intravenous antineoplastic therapy." Journal of Clinical Oncology 40, nr 16_suppl (1.06.2022): 1578. http://dx.doi.org/10.1200/jco.2022.40.16_suppl.1578.
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1578 Background: Acute care visits (emergency department [ED] visits or inpatient admissions) for patients with cancer are growing disproportionately. Traditional oncology care models have not effectively identified and managed at-risk patients to prevent acute care. A next step is to harness advances in technology and mobile applications to enable patients to report symptoms any time, enabling “digital hovering” - intensive monitoring and management of high-risk patients. Our objective was to evaluate a digital platform that identifies and remotely monitors high-risk patients initiating intravenous antineoplastic therapy with the goal of preventing unnecessary acute care visits. Methods: This was a single-institution matched cohort quality improvement study conducted at an NCI-designated cancer center between January 1, 2019 and March 31, 2020. Eligible patients were those initiating intravenous antineoplastic therapy who were identified as high-risk for seeking acute care. Patients were identified as high-risk for an acute care visit by their oncologist with decision support from a web-based machine learning model. Enrolled patients’ symptoms were monitored using a digital platform. The platform is integrated into the EMR and includes: 1) a secure patient portal enabling communication and daily delivery of electronic patient-reported outcomes symptom assessments; 2) clinical alerts for concerning symptoms; and 3) a symptom trending application. A dedicated team of registered nurses and nurse practitioners managed reported symptoms. These clinicians acted as an extension of the primary oncology team, assisting with patient management exclusively through the platform. The primary outcomes evaluated were incidence of ED visits and inpatient admissions within six months of intravenous antineoplastic initiation. Results: Eighty-one high-risk patients from the intervention arm were matched by stage and disease with contemporaneous high-risk control patients. Matched cohorts had similar baseline characteristics, including age, sex, race, and treatment. ED visits and hospitalizations within six months of treatment initiation were analyzed using cumulative incidence analyses with a competing risk of death. The cumulative incidence of an ED visit for the intervention cohort was 0.27 (95% CI: 0.17, 0.37) at six months compared to 0.47 (95% CI: 0.36, 0.58) in the control group (p = 0.01). The cumulative incidence of an inpatient admission was 0.23 (95% CI: 0.14, 0.33) in the intervention group versus 0.41 (95% CI: 0.30, 0.51) in the control group (p = 0.02). Conclusions: The narrow employment of technology solutions to complex care delivery challenges in oncology can improve outcomes and innovate care. This program was a first step in using a digital platform and a remote team to improve symptom care in the home for high-risk patients.
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Molinero, Antonio, Juan Carlos Oller, José Miguel Barcala, Luis Duque, M. Antonia Folgado i Antonio M. Chaparro. "Assembly and Testing of a Hydrogen Fuel Cell System to Power an Airship". ECS Meeting Abstracts MA2022-02, nr 40 (9.10.2022): 1475. http://dx.doi.org/10.1149/ma2022-02401475mtgabs.
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An airship, or dirigible balloon, is an aircraft that gains its lift from a gas less dense than air, like helium. For traction, airships have two or more propellers normally attached to a gondola that is suspended under the balloon. At present, they are used for hovering long times without the need for a high speed, like for aerial observation, advertising, or as camera platforms. In our laboratory, the airship is being used as a platform for testing hydrogen fuel cell systems for aerial applications. The airship used in this communication is a 3 m3 polyurethane's inflatable zeppelin, with radio control, and three electrical propellers (Fig. 1a). A hydrogen fuel cell system has been developed and integrated with the gondola for powering the propellers and electronics. The fuel cell is a 15 W PEMFC stack prototype able to work fully under passive feeding conditions (Fig. 1b). In addition, three supercapacitors have been implemented, that are recharged by the fuel cell, for eventual larger power demands up to 40 W. Hydrogen is stored in two metal hydride canisters with 2g capacity to provide 30 W h energy enough for a few hours autonomy. In addition, for fuel cell parameters monitoring, different sensors have been implemented that provide voltages of the individual cells, current, and temperatures. The sensors are connected to Arduino board, and measurements are continuously monitored by a Labview software with wifi. Boost dc-dc conversion provides 7V voltage power to feed the motors. The stack prototype allows for different testing configurations, using cells in series and parallel connection to change power characteristics with different voltage and current. Results of the testing are provided in this communication. Acknowledgement: The work is partially financed by the ELHYPORT project (PID2019−110896RB-I00), Spanish Ministry of Science and Innovation. Figure 1
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Yin, Xinfan, Xianmin Peng, Guichuan Zhang, Binghui Che i Chang Wang. "Flight Control System Design and Autonomous Flight Control of Small-Scale Unmanned Helicopter Based on Nanosensors". Journal of Nanoelectronics and Optoelectronics 16, nr 4 (1.04.2021): 675–88. http://dx.doi.org/10.1166/jno.2021.2996.
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Due to the limitation of the size and power, micro unmanned aerial vehicle (MUAV) usually has a small load capacity. Aiming at the problems of limited installation space and easy being interfered in flight attitude measurement of the small-scale unmanned helicopter (SUH), a low-cost and lightweight flight control system of the SUH based on ARM Cortex-M4 core microcontroller and Micro-Electro-Mechanical Systems (MEMS) sensors is developed in this paper. On this basis, in order to realize the autonomous flight control of SUH, firstly, the mathematical model of the SUH is given by using the Newton-Euler formulation. Secondly, a cascade flight controller consisting of the attitude controller and the position controller is developed based on linear active disturbance rejection control (LADRC) and proportional-integral-derivative (PID) control. Furthermore, simulations are conducted to validate the performance of the attitude controller and the position controller in MATLAB/SIMULINK simulation environment. Finally, based on the Align T-REX 470L SUH experimental platform, the hovering experiment and the route flight experiment are also carried out to validate the performance of the designed flight control system hardware and the proposed control algorithm. The results show that the flight control system designed in this paper has high reliability and strong anti-interference ability, and the control algorithm can effectively and reliably realize the attitude stabilization control and route control of the SUH, with high control accuracy and small error.
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Hegde, Navya Thirumaleshwar, Aldrin Claytus Vaz i C. G. Nayak. "Closed Loop Performance Analysis of Classical PID and Robust H-infinity Controller for VTOL Unmanned Quad Tiltrotor Aerial Vehicle". International Journal of Mechanics 15 (4.10.2021): 211–22. http://dx.doi.org/10.46300/9104.2021.15.25.
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Unmanned Aerial Vehicles (UAVs) guidance, control and navigation have directed the attention of many researchers in both aerospace engineering as well as control theory. Due to the unique rotor structure of Tiltrotor hybrid UAVs, they exhibit special application value. Quad Tiltrotor UAVs set up a distinctive platform that satisfies the needs of the varying mission requirements by combining the conventional features of high-speed cruise capabilities of an aircraft and hovering capabilities of a helicopter and by tilting its four rotors. The aim of this research article is to control the attitude and altitude of the UAV in the presence of uncertainty using two different control techniques. This paper addresses the comparative analysis of the robust H-infinity controller with classical PID control designs for the transition manoeuvre of a hybrid UAV: the VTOL Tiltrotor UAV. The proposed controllers achieve hover to cruise mode transition and vice-versa. The main idea behind the design of controller is to model and analyze the UAV’s position and attitude dynamics. The desired flight trajectory and the transition manoeuvre is achieved by controlling the tilt angle in 15° intervals from 90° to 0° and vice-versa. Performance index subjected to IAE is estimated and compared for both the controllers in the presence of noise, disturbances and uncertainties. The results of simulation illustrate that the robust H-infinity controller achieves better transition, good adaptability, robust performance and robust stability for the whole flight envelope when compared with the PID controller.
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Wang, Ruilin, Zhiqing Li, Shugen Ma i Xiaosong An. "Development of an Underwater Detection Robot". Journal of Physics: Conference Series 2203, nr 1 (1.02.2022): 012008. http://dx.doi.org/10.1088/1742-6596/2203/1/012008.
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Abstract The ocean contains huge valuable resources, due to the huge pressure in the deep water and the danger of diving, human development is very little. In this paper, we design a small underwater observation robot, which can replace human beings to dive into deep water, detect the deepwater area and sample the water quality. Following the principle of fish diving, the robot uses the piston bucket to pump water and drain water to change its gravity to achieve floating and diving. The main propeller at the tail provides the main driving force. The robot turns by propellers on both sides working at different speeds and propellers can change the thrust direction to provide assist force in the process of diving and floating. The structure design of the tumbler(the design of anti-roll) ensures the anti-interference ability of the robot to the wind and wave. In addition, the robot can be equipped with cameras, depth sensors, temperature and humidity sensors, and other sensors to achieve efficient underwater data sampling. The depth sensor, propeller, and pumping piston are used to control the hovering depth of the robot. The ROV can record good quality of video if provided with proper video graphic tool. The design of ROV which we have conceptualize, is handy and can be powered by 24V DC power which can be easily available at remote location. The experimental results verify the structural reliability of the underwater detection robot and provide a new mobile mechanism platform and a new idea for deep-sea exploration and scientific research.
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Lawrence, Colleen E., Leah Dunkel, Mark McEver, Tiffany Israel, Robert Taylor, Germán Chiriboga, Karin Valentine Goins i in. "A REDCap-based model for electronic consent (eConsent): Moving toward a more personalized consent". Journal of Clinical and Translational Science 4, nr 4 (3.04.2020): 345–53. http://dx.doi.org/10.1017/cts.2020.30.
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AbstractIntroduction:The updated common rule, for human subjects research, requires that consents “begin with a ‘concise and focused’ presentation of the key information that will most likely help someone make a decision about whether to participate in a study” (Menikoff, Kaneshiro, Pritchard. The New England Journal of Medicine. 2017; 376(7): 613–615.). We utilized a community-engaged technology development approach to inform feature options within the REDCap software platform centered around collection and storage of electronic consent (eConsent) to address issues of transparency, clinical trial efficiency, and regulatory compliance for informed consent (Harris, et al. Journal of Biomedical Informatics 2009; 42(2): 377–381.). eConsent may also improve recruitment and retention in clinical research studies by addressing: (1) barriers for accessing rural populations by facilitating remote consent and (2) cultural and literacy barriers by including optional explanatory material (e.g., defining terms by hovering over them with the cursor) or the choice of displaying different videos/images based on participant’s race, ethnicity, or educational level (Phillippi, et al. Journal of Obstetric, Gynecologic, & Neonatal Nursing. 2018; 47(4): 529–534.).Methods:We developed and pilot tested our eConsent framework to provide a personalized consent experience whereby users are guided through a consent document that utilizes avatars, contextual glossary information supplements, and videos, to facilitate communication of information.Results:The eConsent framework includes a portfolio of eight features, reviewed by community stakeholders, and tested at two academic medical centers.Conclusions:Early adoption and utilization of this eConsent framework have demonstrated acceptability. Next steps will emphasize testing efficacy of features to improve participant engagement with the consent process.
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Panigrahi, Siddhant, Yenugu Siva Sai Krishna i Asokan Thondiyath. "Design, Analysis, and Testing of a Hybrid VTOL Tilt-Rotor UAV for Increased Endurance". Sensors 21, nr 18 (7.09.2021): 5987. http://dx.doi.org/10.3390/s21185987.
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Unmanned Aerial Vehicles (UAVs) have slowly but steadily emerged as a research and commercial hotspot because of their widespread applications. Due to their agility, compact size, and ability to integrate multiple sensors, they are mostly sought for applications that require supplementing human effort in risky and monotonous missions. Despite all of these advantages, rotorcrafts, in general, are limited by their endurance and power-intensive flight requirements, which consequently affect the time of flight and operational range. On the other hand, fixed-wing aircrafts have an extended range, as the entire thrust force is along the direction of motion and are inherently more stable but are limited by their takeoff and landing strip requirements. One of the potential solutions to increase the endurance of VTOL rotorcrafts (Vertical Take-Off and Landing Vehicles) was to exploit the thrust vectoring ability of the individual actuators in multi-rotors, which would enable take-off and hovering as a VTOL vehicle and flight as a fixed-wing aircraft. The primary aim of this paper is to lay out the overall design process of a Hybrid VTOL tilt-rotor UAV from the initial conceptual sketch to the final fabricated prototype. The novelty of the design lies in achieving thrust vectoring capabilities in a fixed-wing platform with minimum actuation and no additional control complexity. This paper presents novel bi-copter that has been designed to perform as a hybrid configuration in both VTOL and fixed wing conditions with minimum actuators in comparison to existing designs. The unified dynamic modelling along with the approximation of multiple aerodynamic coefficients by numerical simulations is also presented. The overall conceptual design, dynamic modeling, computational simulation, and experimental analysis of the novel hybrid fixed-wing bi-copter with thrust vectoring capabilities aiming to substantially increase the flight range and endurance compared to the conventional aircraft rotorcraft configurations are presented.
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Anisimov, A., O. Volkov, Ya Linder, V. Taranukha i D. Volosheniuk. "THE METHOD OF ACOUSTIC DIRECTION FINDING OF DYNAMIC OBJECTS USING AN UNMANNED AERIAL VEHICLE". Collection of scientific works of the Military Institute of Kyiv National Taras Shevchenko University, nr 64 (2019): 14–24. http://dx.doi.org/10.17721/2519-481x/2019/64-02.
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The article describes the method of creation, structure and operation of the method for determining the direction to the sound source. The method relies on a simple mathematical apparatus, which allows it to be implemented on equipment of minimal power, for example, on Arduino microprocessors. The key elements of the method and conditions of use affecting the result are considered. These include the sound parameters of targets, primarily the main frequencies and duration of sound necessary to reliably determine the direction to the sound source. In addition, the method provides means for estimating environmental parameters in order to determine the speed of sound depending on weather conditions, since the results of the method are highly dependent on this parameter. Recommendations have been developed for UAVs on which it will be necessary to install equipment, and the use is described to obtain better results in determining directions to sound sources. Demonstrated proof of the formula that allows one to determine the direction to the sound source, given that the platform where the hardware-software complex will be mounted must move and carry out the determination of the direction to the sound source during movement or, in the worst case, short stops for hovering. For this formula the angle error in degrees is estimated depending on the angle at which the sound wave arrives relatively to direction of movement. Software prototyping was performed for further implementation in the form of a full-fledged software and hardware complex for installation on UAVs. The graphical interface of the software implementation of the method is also presented. The simulation of the system under various circumstances was performed. During the experiments, a threshold value was determined for the key criterion, it is based on the signal-to-noise ratio since the method will not work in a too noisy environment. The experiments performed shown the high efficiency of the method taking into account the features of real sound sources.
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Avanzini, Giulio, Emanuele L. de Angelis, Fabrizio Giulietti i Edmondo Minisci. "Optimal Sizing of Electric Multirotor Configurations". MATEC Web of Conferences 233 (2018): 00028. http://dx.doi.org/10.1051/matecconf/201823300028.
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A sizing tool for the definition of the configuration of electrically powered multirotor platforms is developed, which accounts for a realistic battery discharge model. The tool is developed to provide the community with the possibility of deriving the best configuration for performing a given task, while accounting for specific constraints and performance requirements. An evolutionary algorithm is used for searching the design space and to identify feasible designs with optimal performance in terms of maximum hovering time on the target and payload weight fraction.
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Briod, Adrien, Jean-Christophe Zufferey i Dario Floreano. "A method for ego-motion estimation in micro-hovering platforms flying in very cluttered environments". Autonomous Robots 40, nr 5 (15.09.2015): 789–803. http://dx.doi.org/10.1007/s10514-015-9494-4.
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