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Dynamic flight stability of a hovering model insect:lateral motion 被引量:17
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作者 Yanlai Zhang Mao Sun 《Acta Mechanica Sinica》 SCIE EI CAS CSCD 2010年第2期175-190,共16页
The lateral dynamic flight stability of a hovering model insect (dronefly) was studied using the method of computational fluid dynamics to compute the stability derivatives and the techniques of eigenvalue and eigen... The lateral dynamic flight stability of a hovering model insect (dronefly) was studied using the method of computational fluid dynamics to compute the stability derivatives and the techniques of eigenvalue and eigenvector analysis for solving the equations of motion. The main results are as following. (i) Three natural modes of motion were identified: one unstable slow divergence mode (mode 1), one stable slow oscillatory mode (mode 2), and one stable fast subsidence mode (mode 3). Modes 1 and 2 mainly consist of a rotation about the horizontal longitudinal axis (x-axis) and a side translation; mode 3 mainly consists of a rotation about the x-axis and a rotation about the vertical axis. (ii) Approximate analytical expressions of the eigenvalues are derived, which give physical insight into the genesis of the natural modes of motion. (iii) For the unstable divergence mode, td, the time for initial disturbances to double, is about 9 times the wingbeat period (the longitudinal motion of the model insect was shown to be also unstable and td of the longitudinal unstable mode is about 14 times the wingbeat period). Thus, although the flight is not dynamically stable, the instability does not grow very fast and the insect has enough time to control its wing motion to suppress the disturbances. 展开更多
关键词 INSECT Dynamic flight stability hovering ·Lateral motion Natural modes of motion
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Control for going from hovering to small speed flight of a model insect 被引量:5
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作者 Jianghao Wu Mao Sun 《Acta Mechanica Sinica》 SCIE EI CAS CSCD 2009年第3期295-302,共8页
The longitudinal steady-state control for going from hovering to small speed flight of a model insect is studied, using the method of computational fluid dynamics to compute the aerodynamic derivatives and the techniq... The longitudinal steady-state control for going from hovering to small speed flight of a model insect is studied, using the method of computational fluid dynamics to compute the aerodynamic derivatives and the techniques based on the linear theories of stability and control for determining the non-zero equilibrium points. Morphological and certain kinematical data of droneflies are used for the model insect. A change in the mean stroke angle (δФ) results in a horizontal forward or backward flight; a change in the stroke amplitude (δФ) or a equal change in the down- and upstroke angles of attack (δα1) results in a vertical climb or decent; a proper combination of δФ and δФ controls (or δФ and δα1 controls) can give a flight of any (small) speed in any desired direction. 展开更多
关键词 Insect. Flight control hovering Small speed flight
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Aerodynamics of flexible wing in bees' hovering flight
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作者 尹东富 张志胜 《Journal of Southeast University(English Edition)》 EI CAS 2013年第4期419-424,共6页
The aerodynamics of 2-dimensional flexible wings in bees' normal hovering flight is studied. Four insect flapping flight coordinate systems, including a global system, a bodyfixed system, a rigid wing-fixed system an... The aerodynamics of 2-dimensional flexible wings in bees' normal hovering flight is studied. Four insect flapping flight coordinate systems, including a global system, a bodyfixed system, a rigid wing-fixed system and a flexible wingfixed system, are established to represent the insects' position, gesture, wing movement and wing deformation, respectively. Then the transformations among four coordinate systems are studied. It is found that the elliptic coordinate system can improve the computation accuracy and reduce the calculation complexity in a 2-dimensional rigid wing. The computation model of a 2-dimensional flexible wing is established, and the changes of the force, moment, and power are investigated. According to the computation results, the large lift and drag peaks at the beginning and end of the stroke can be explained by the superposition of the rapid translational acceleration, the fast pitching-up rotation and the Magnus effect; and the small force and drag peaks can be explained by the convex flow effect and the concave flow effect. Compared with the pressure force, pressure moment and translational power, the viscous force, viscous moment and rotational power are small and can be ignored. 展开更多
关键词 flapping wing coordinate systems hovering flight computational fluid dynamics aerodynamics force Dower
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Hover performance estimation and validation of battery powered vertical takeoff and landing aircraft 被引量:2
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作者 王波 侯中喜 +1 位作者 鲁亚飞 朱雄峰 《Journal of Central South University》 SCIE EI CAS CSCD 2016年第10期2595-2603,共9页
Battery powered vertical takeoff and landing(VTOL) aircraft attracts more and more interests from public, while limited hover endurance hinders many prospective applications. Based on the weight models of battery, mot... Battery powered vertical takeoff and landing(VTOL) aircraft attracts more and more interests from public, while limited hover endurance hinders many prospective applications. Based on the weight models of battery, motor and electronic speed controller, the power consumption model of propeller and the constant power discharge model of battery, an efficient method to estimate the hover endurance of battery powered VTOL aircraft was presented. In order to understand the mechanism of performance improvement, the impacts of propulsion system parameters on hover endurance were analyzed by simulations, including the motor power density, the battery capacity, specific energy and Peukert coefficient. Ground experiment platform was established and validation experiments were carried out, the results of which showed a well agreement with the simulations. The estimation method and the analysis results could be used for optimization design and hover performance evaluation of battery powered VTOL aircraft. 展开更多
关键词 vertical takeoff and landing hover endurance estimation battery powered aircraft experimental validation
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Near wake vortex dynamics of a hovering hawkmoth 被引量:2
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作者 Hikaru Aono Wei Shyy Hao Liu 《Acta Mechanica Sinica》 SCIE EI CAS CSCD 2009年第1期23-36,共14页
Numerical investigation of vortex dynamics in near wake of a hovering hawkmoth and hovering aerodynamics is conducted to support the development of a biology-inspired dynamic flight simulator for flapping wingbased mi... Numerical investigation of vortex dynamics in near wake of a hovering hawkmoth and hovering aerodynamics is conducted to support the development of a biology-inspired dynamic flight simulator for flapping wingbased micro air vehicles. Realistic wing-body morphologies and kinematics are adopted in the numerical simulations. The computed results show 3D mechanisms of vortical flow structures in hawkmoth-like hovering. A horseshoe-shaped primary vortex is observed to wrap around each wing during the early down- and upstroke; the horseshoe-shaped vortex subsequently grows into a doughnut-shaped vortex ring with an intense jet-flow present in its core, forming a downwash. The doughnut-shaped vortex rings of the wing pair eventu- ally break up into two circular vortex rings as they propagate downstream in the wake. The aerodynamic yawing and rolling torques are canceled out due to the symmetric wing kinematics even though the aerodynamic pitching torque shows significant variation with time. On the other hand, the time- varying the aerodynamics pitching torque could make the body a longitudinal oscillation over one flapping cycle. 展开更多
关键词 AERODYNAMICS hovering Hawkmoth Vortical flow structure
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Dynamic flight stability of hovering model insects:theory versus simulation using equations of motion coupled with Navier-Stokes equations 被引量:9
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作者 Yan-Lai Zhang Mao Sun 《Acta Mechanica Sinica》 SCIE EI CAS CSCD 2010年第4期509-520,共12页
In the present paper, the longitudinal dynamic flight stability properties of two model insects are predicted by an approximate theory and computed by numerical sim- ulation. The theory is based on the averaged model ... In the present paper, the longitudinal dynamic flight stability properties of two model insects are predicted by an approximate theory and computed by numerical sim- ulation. The theory is based on the averaged model (which assumes that the frequency of wingbeat is sufficiently higher than that of the body motion, so that the flapping wings' degrees of freedom relative to the body can be dropped and the wings can be replaced by wingbeat-cycle-average forces and moments); the simulation solves the complete equations of motion coupled with the Navier-Stokes equations. Comparison between the theory and the simulation provides a test to the validity of the assumptions in the theory. One of the insects is a model dronefly which has relatively high wingbeat frequency (164 Hz) and the other is a model hawkmoth which has relatively low wingbeat frequency (26 Hz). The results show that the averaged model is valid for the hawkmoth as well as for the dronefly. Since the wingbeat frequency of the hawkmoth is relatively low (the characteristic times of the natural modes of motion of the body divided by wingbeat period are relatively large) compared with many other insects, that the theory based on the averaged model is valid for the hawkmoth means that it could be valid for many insects. 展开更多
关键词 Insect hovering Dynamic flight stability Averaged model Equations-of-motion Navier-Stokes simulation
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Stabilization control of a hovering model insect:lateral motion 被引量:1
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作者 Yan-Lai Zhang Mao Sun 《Acta Mechanica Sinica》 SCIE EI CAS CSCD 2011年第5期823-832,共10页
Our previous study shows that the lateral disturbance motion of a model drone fly does not have inherent stability (passive stability),because of the existence of an unstable divergence mode.But drone flies are obse... Our previous study shows that the lateral disturbance motion of a model drone fly does not have inherent stability (passive stability),because of the existence of an unstable divergence mode.But drone flies are observed to fly stably.Constantly active control must be applied to stabilize the flight.In this study,we investigate the lateral stabilization control of the model drone fly.The method of computational fluid dynamics is used to compute the lateral control derivatives and the techniques of eigenvalue and eigenvector analysis and modal decomposition are used for solving the equations of motion.Controllability analysis shows that although inherently unstable,the lateral disturbance motion is controllable.By feeding back the state variables (i.e.lateral translation velocity,yaw rate,roll rate and roll angle,which can be measured by the sensory system of the insect) to produce anti-symmetrical changes in stroke amplitude and/or in angle of attack between the left and right wings,the motion can be stabilized,explaining why the drone flies can fly stably even if the flight is passively unstable. 展开更多
关键词 hovering drone fly Lateral motion Flight stability Stabilization control Modal analysis
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Lateral dynamic flight stability of hovering insects: theory vs. numerical simulation 被引量:4
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作者 Yan-Lai Zhang Jiang-Hao Wu Mao Sun 《Acta Mechanica Sinica》 SCIE EI CAS CSCD 2012年第1期221-231,共11页
In the present paper, the lateral dynamic flight stability properties of two hovering model insects are predicted by an approximate theory based on the averaged model, and computed by numerical simulation that solves ... In the present paper, the lateral dynamic flight stability properties of two hovering model insects are predicted by an approximate theory based on the averaged model, and computed by numerical simulation that solves the complete equations of motion coupled with the Naviertokes equations. Comparison between the theoretical and simulational results provides a test to the validity of the assumptions made in the theory. One of the insects is a model dronefly which has relatively high wingbeat frequency (164Hz) and the other is a model hawkmoth which has relatively low wingbeat frequency (26 Hz). The following conclusion has been drawn. The theory based on the averaged model works well for the lateral motion of the dronefly. For the hawkmoth, relatively large quantitative differences exist between theory and simulation. This is because the lateral non-dimensional eigenvalues of the hawkmoth are not very small compared with the non-dimensional flapping frequency (the largest lateral non-dimensional eigenvalue is only about 10% smaller than the non-dimensional flapping frequency). Nevertheless, the theory can still correctly predict variational trends of the dynamic properties of the hawkmoth's lateral motion. 展开更多
关键词 Insect - hovering Lateral dynamic flight stabil- ity Averaged model Equations-of-motion Navier-Stokes simulation
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Stabilization control of a bumblebee in hovering and forward flight 被引量:1
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作者 Yan Xiong Mao Sun Institute of Fluid Mechanics, Beihang University,Beijing 100083, China 《Acta Mechanica Sinica》 SCIE EI CAS CSCD 2009年第1期13-21,共9页
Our previous study shows that the hovering and forward flight of a bumblebee do not have inherent stability (passive stability). But the bumblebees are observed to fly stably. Stabilization control must have been ap... Our previous study shows that the hovering and forward flight of a bumblebee do not have inherent stability (passive stability). But the bumblebees are observed to fly stably. Stabilization control must have been applied. In this study, we investigate the longitudinal stabilization control of the bumblebee. The method of computational fluid dynamics is used to compute the control derivatives and the techniques of eigenvalue and eigenvector analysis and modal decomposition are used for solving the equations of motion. Controllability analysis shows that at all flight speeds considered, although inherently unstable, the flight is controllable. By feedbacking the state variables, i.e. vertical and horizontal velocities, pitching rate and pitch angle (which can be measured by the sensory system of the insect), to produce changes in stroke angle and angle of attack of the wings, the flight can be stabilized, explaining why the bumblebees can fly stably even if they are passively unstable. 展开更多
关键词 Insect - hovering and forward flight - Stabilization control Navier-Stokes simulation Modal analysis
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Research on Aerodynamic Characteristics of Hovering Rotor Based on Leading Edge Droop 被引量:1
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作者 LI Congcong SHI Yongjie +1 位作者 XU Guohua MA Taihang 《Transactions of Nanjing University of Aeronautics and Astronautics》 EI CSCD 2021年第S01期10-16,共7页
In view of the reduction of hovering efficiency near high tension when a helicopter rotor hovers,a numerical simulation method of lifting rotor hovering aerodynamic characteristics based on leading edge droop is estab... In view of the reduction of hovering efficiency near high tension when a helicopter rotor hovers,a numerical simulation method of lifting rotor hovering aerodynamic characteristics based on leading edge droop is established in this paper. It is dominated by Reynolds average N-S equation in integral form. Firstly,VR-12 airfoil is taken as the research object,and the influence of leading edge droop angle on the aerodynamic characteristics of two-dimensional airfoil is studied. Secondly,the modified 7 A rotor is taken as the research object,and the effects of different leading edge droop angles at the position of blade r/R=0.75—1 on the aerodynamic characteristics in hover are explored. It is found that the leading edge droop can significantly improve the aerodynamic characteristics of two-dimensional airfoil and three-dimensional hovering rotor near high angle of attack,and can effectively inhibit the generation of stall vortex. 展开更多
关键词 helicopter rotor hovering leading edge droop aerodynamic characteristics
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A Study on Hovering Control of Small Aerial Robot by Sensing Existing Floor Features 被引量:1
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作者 Chinthaka Premachandra Dang Ngoc Hoang Thanh +1 位作者 Tomotaka Kimura Hiroharu Kawanaka 《IEEE/CAA Journal of Automatica Sinica》 SCIE EI CSCD 2020年第4期1016-1025,共10页
Since precise self-position estimation is required for autonomous flight of aerial robots, there has been some studies on self-position estimation of indoor aerial robots. In this study, we tackle the self-position es... Since precise self-position estimation is required for autonomous flight of aerial robots, there has been some studies on self-position estimation of indoor aerial robots. In this study, we tackle the self-position estimation problem by mounting a small downward-facing camera on the chassis of an aerial robot. We obtain robot position by sensing the features on the indoor floor.In this work, we used the vertex points(tile corners) where four tiles on a typical tiled floor connected, as an existing feature of the floor. Furthermore, a small lightweight microcontroller is mounted on the robot to perform image processing for the onboard camera. A lightweight image processing algorithm is developed. So, the real-time image processing could be performed by the microcontroller alone which leads to conduct on-board real time tile corner detection. Furthermore, same microcontroller performs control value calculation for flight commanding. The flight commands are implemented based on the detected tile corner information. The above mentioned all devices are mounted on an actual machine, and the effectiveness of the system was investigated. 展开更多
关键词 hovering control light weight algorithm development image processing self-position estimation small aerial robot tile corner sensing
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Numerical analysis of the three-dimensional aerodynamics of a hovering rufous hummingbird(Selasphorus rufus) 被引量:2
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作者 Songyuan Yang Weiping Zhang 《Acta Mechanica Sinica》 SCIE EI CAS CSCD 2015年第6期931-943,共13页
Hummingbirds have a unique way of hover- ing. However, only a few published papers have gone into details of the corresponding three-dimensional vortex struc- tures and transient aerodynamic forces. In order to deepen... Hummingbirds have a unique way of hover- ing. However, only a few published papers have gone into details of the corresponding three-dimensional vortex struc- tures and transient aerodynamic forces. In order to deepen the understanding in these two realms, this article presents an integrated computational fluid dynamics study on the hovering aerodynamics of a rufous hummingbird. The original morphological and kinematic data came from a former researcher's experiments. We found that conical and sta- ble leading-edge vortices (LEVs) with spanwise flow inside their cores existed on the hovering hummingbird's wing surfaces. When the LEVs and other near-field vortices were all shed into the wake after stroke reversals, periodically shed bilateral vortex rings were formed. In addition, a strong downwash was present throughout the flapping cycle. Time histories of lift and drag were also obtained. Combining the three-dimensional flow field and time history of lift, we believe that high lift mechanisms (i.e., rotational circulation and wake capture) which take place at stroke reversals in insect flight was not evident here. For mean lift throughout a whole cycle, it is calculated to be 3.60 g (104.0 % of the weight support). The downstroke and upstroke provide 64.2 % and 35.8 % of the weight support, respectively. 展开更多
关键词 Rufous hummingbird · Selasphorus rufus·hovering · Aerodynamics · Computational fluid dynamics(CFD)
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Methods of spacecraft impulsive relative hovering and trajectory safety analysis
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作者 CHENG Bo YUAN Jianping +1 位作者 QIAN Yingjing MA Weihua 《中国空间科学技术》 EI CSCD 北大核心 2017年第6期89-98,共10页
Based on the analytical solutions of T-H equations and its state transition matrix form,the open-loop control method of spacecraft impulsive relative hovering was studied,which is promising for practical engineering u... Based on the analytical solutions of T-H equations and its state transition matrix form,the open-loop control method of spacecraft impulsive relative hovering was studied,which is promising for practical engineering use.The true anomaly intervals of the hovering impulse were optimized by the nonlinear mathematical programming.Based on the calculation of collision probability,the method of safety analysis and risk management was proposed.The numerical simulations show that the introduced relative hovering method can be used for circular and elliptical reference orbits hovering.Furthermore,the local optimal solution can be obtained by applying the true anomaly intervals optimization method.The maximum collision probability and the minimum relative distance nearly appear at the same time.And,the smaller the relative distance is,the larger the collision probability. 展开更多
关键词 SPACECRAFT impulsive hovering collision probability trajectory safety
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High-Order Discontinuous Galerkin Method for Hovering Rotor Simulations Based on a Rotating Reference Frame
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作者 ZHANG Tao Lü Hongqiang +1 位作者 QIN Wanglong CHEN Zhengwu 《Transactions of Nanjing University of Aeronautics and Astronautics》 EI CSCD 2019年第1期57-70,共14页
An implicit higher ? order discontinuous Galerkin(DG) spatial discretization for the compressible Euler equations in a rotating frame of reference is presented and applied to a rotor in hover using hexahedral grids. I... An implicit higher ? order discontinuous Galerkin(DG) spatial discretization for the compressible Euler equations in a rotating frame of reference is presented and applied to a rotor in hover using hexahedral grids. Instead of auxiliary methods like grid adaptation,higher ? order simulations(fourth ? and fifth ? order accuracy) are adopted.Rigorous numerical experiments are carefully designed,conducted and analyzed. The results show generally excellent consistence with references and vigorously demonstrate the higher?order DG method's better performance in loading distribution computations and tip vortex capturing, with much fewer degrees of freedom(DoF). Detailed investigations on the outer boundary conditions for hovering rotors are presented as well. A simple but effective speed smooth procedure is developed specially for the DG method. Further results reveal that the rarely used pressure restriction for outlet speed has a considerable advantage over the extensively adopted vertical speed restriction. 展开更多
关键词 high-order method(HOM) discontinuous Glaerkin method(DGM) Euler equation hovering rotor simulation tip vortex
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Research on the attitude regulation of 3-DOF hover system
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作者 胡琼 费庆 +1 位作者 伍清河 耿庆波 《Journal of Beijing Institute of Technology》 EI CAS 2013年第4期483-491,共9页
Quadrotor helicopter is emerging as a popular platform for unmanned aerial vehicle re- search, due to its simplicity of structure and maintenance as well as the capability of hovering and vertical take-off and landing... Quadrotor helicopter is emerging as a popular platform for unmanned aerial vehicle re- search, due to its simplicity of structure and maintenance as well as the capability of hovering and vertical take-off and landing. The attitude controller is an important feature of quadrotor helicopter since it allows the vehicle to keep balance and perform the desired maneuver. In this paper, nonlin- ear control strategies including active disturbance rejection control (ADRC), sliding mode control (SMC) and backstepping method are studied and implemented to stabilize the attitude of a 3-DOF hover system. ADRC is an error-driven control law, with extended state observer (ESO) estimating the unmodeled inner dynamics and external disturbance to dynamically compensate their impacts. Meanwhile; both backstepping technique and SMC are developed based on the mathematical model, whose stability is ensured by Lyapunov global stability theorem. Furthermore, the performance of each control algorithm is evaluated by experiments. The results validate effectiveness of the strate- gies for attitude regulation. Finally, the respective characteristics of the three controllers are high- lighted by-comparison, and conclusions are drawn on the basis of the theoretical and experimental a- nalysis. 展开更多
关键词 3-DOF hover system dynamics attitude regulation active disturbance rejection control(ADRC) Lyapunov global stability theorem backstepping sliding mode control
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Robust Near-Hovering Flight Controller for Model-Scale Helicopters Via Parametric Approach
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作者 Zhigang Zhou Yongan Zhang 《Journal of Harbin Institute of Technology(New Series)》 EI CAS 2015年第5期69-77,共9页
This paper aims to provide a parametric design for robust flight controller of the model-scale helicopter. The main contributions lie in two aspects. Firstly,under near-hovering condition,a procedure is presented for ... This paper aims to provide a parametric design for robust flight controller of the model-scale helicopter. The main contributions lie in two aspects. Firstly,under near-hovering condition,a procedure is presented for simplification of the highly nonlinear and under-actuated model of the model-scale helicopter. This nonlinear system is linearized around the trim values of the chosen flight mode,followed by decomposing this high-order linear model into three lower-order subsystems according to the coupling properties among channels.After decomposition,the three subsystems are obtained which include the coupling subsystem between the roll( pitch) motion and the lateral( longitudinal) motion,the subsystem of the yaw motion and the subsystem of the vertical motion. Secondly,by using eigenstructure assignment,the problem of flight controller design can be converted into solving two optimization problems and the linear robust controllers of these subsystems are designed through solving these optimization problems. Besides, this paper contrasts and analyzed the performances of the LQR controller and the parametric controller. The results demonstrate the effectiveness and the robustness against the parametric perturbations of the parametric controller. 展开更多
关键词 model-scale helicopter near-hovering robust flight controller robust eigenstructure assignment
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8万元家庭装 GREAT WALL HOVER H3
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作者 佳俊 冯欣 《世界汽车》 2009年第7期86-89,共4页
对于一款各方面都还不错的SUV来说,8万元的价格着实非常吸引人。然而低价位并不意味着低含金量,单从这款车的设计定位及性能来看,满足一般家庭使用绰绰有余。
关键词 家庭 SUV 含金量 低价位 轿车 GREAT WALL hover H3
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Eagles Are Hovering at the Cradle of Love Songs
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作者 Yi Shizhong Bao Lida 《China's Tibet》 2008年第3期69-70,共2页
In the late autumn of 2007,the Southwest Branch of China Airlines sent offone A319 airbus,named B6238,to cross over Mt.Gongkya (7556 meters above sea level) and safely land at the Kangding Airport - which is acknowled... In the late autumn of 2007,the Southwest Branch of China Airlines sent offone A319 airbus,named B6238,to cross over Mt.Gongkya (7556 meters above sea level) and safely land at the Kangding Airport - which is acknowledged as the world's second highest airport.The success of the experimental flight ends the history of unavailabil- ity of civil airline flights in Garze Autonomous Prefecture of Sichuan Province.It also marks the closure of the final preparation phase and readiness to move to the next stage-l... 展开更多
关键词 Eagles Are hovering at the Cradle of Love Songs
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Lift system optimization for hover-capable flapping wing micro air vehicle
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作者 Shengjie XIAO Yongqi SHI +4 位作者 Zemin WANG Zhe NI Yuhang ZHENG Huichao DENG Xilun DING 《Frontiers of Mechanical Engineering》 SCIE CSCD 2024年第3期61-75,共15页
A key challenge is using bionic mechanisms to enhance aerodynamic performance of hover-capable flapping wing micro air vehicle(FWMAV).This paper presented a new lift system with high lift and aerodynamic efficiency,wh... A key challenge is using bionic mechanisms to enhance aerodynamic performance of hover-capable flapping wing micro air vehicle(FWMAV).This paper presented a new lift system with high lift and aerodynamic efficiency,which use a hummingbird as a bionic object.This new lift system is able to effectively utilize the high lift mechanism of hummingbirds,and this study innovatively utilizes elastic energy storage elements and installs them at the wing root to help improve aerodynamic performance.A flapping angle of 154°is achieved through the optimization of the flapping mechanism parameters.An optimized wing shape and parameters are obtained through experimental studies on the wings.Consequently,the max net lift generated is 17.6%of the flapping wing vehicle’s weight.Moreover,energy is stored and released periodically during the flapping cycle,by imitating the musculoskeletal system at the wing roots of hummingbirds,thereby improving the energy utilization rate of the FWMAV and reducing power consumption by 4.5%under the same lift.Moreover,strength verification and modal analyses are conducted on the flapping mechanism,and the weight of the flapping mechanism is reduced through the analysis and testing of different materials.The results show that the lift system can generate a stable lift of 31.98 g with a wingspan of 175 mm,while the lift system weighs only 10.5 g,providing aerodynamic conditions suitable for high maneuverability flight of FWMAVs. 展开更多
关键词 lift optimization flapping wing elastic energy hovering flapping mechanism
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倾转旋翼机悬停状态气动干扰分析 被引量:1
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作者 李尚斌 江露生 林永峰 《工程力学》 EI CSCD 北大核心 2024年第3期232-240,共9页
针对倾转旋翼机,开展了悬停状态气动干扰风洞试验和数值模拟研究。试验中,测量了悬停状态下的旋翼升力、扭矩以及半模机翼的气动力。同时,采用运动嵌套网格方法,通过求解N-S方程对机翼倾角0°和90°两种状态进行数值模拟,开展... 针对倾转旋翼机,开展了悬停状态气动干扰风洞试验和数值模拟研究。试验中,测量了悬停状态下的旋翼升力、扭矩以及半模机翼的气动力。同时,采用运动嵌套网格方法,通过求解N-S方程对机翼倾角0°和90°两种状态进行数值模拟,开展了数值模拟与风洞试验的相关性分析研究,验证了该数值模拟方法的有效性。结果表明:不考虑机身气动力时,孤立旋翼、机翼攻角0°和机翼攻角90°三种状态下旋翼气动特性差异不明显;考虑机身气动力时,机翼攻角0°时,机身产生约18.2%向下载荷,单片桨叶和机身出现强烈非定常气动特性,其中桨叶升力系数动态值与平均值比为9.8%,机身升力系数动态值与平均值比为18.38%。 展开更多
关键词 倾转旋翼机 气动干扰 风洞试验 数值模拟 悬停状态
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