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flying South

小学生时代（大嘴英语） 2022年第10期 10-15页

作者： J Victor Tsway 不详

Dear Big Mouth English readers,Fall is coming.Today,we take a look at birds in fall.Can you guess what we are going to talk about?

关键词： guess flying birds

Spacecraft formation-containment flying control with time-varying translational velocity

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Chinese Journal of Aeronautics 2020年第1期33卷 271-281页

作者： Liangming CHEN Chuanjiang LI Yanning GUO Guangfu MA Baolong ZHU Department of Control Science and Engineering Harbin Institute of TechnologyHarbin 150001China School of Electrical Engineering and Automation Qilu University of Technology(Shandong Academy of Sciences)Jinan 250353China

This paper investigates the problem of Spacecraft Formation-Containment flying Control(SFCFC)when the desired translational velocity is time-varying.In SFCFC problem,there are multiple leader spacecraft and multiple follower spacecraft and SFCFC can be divided into leader spacecraft’s formation control and follower spacecraft’s containment control.First,under the condition that only a part of leader spacecraft can have access to the desired time-varying translational velocity,a velocity estimator is designed for each leader spacecraft.Secondly,based on the estimated translational velocity,a distributed formation control algorithm is designed for leader spacecraft to achieve the desired formation and move with the desired translational velocity simultaneously.Then,to ensure all follower spacecraft converge to the convex hull formed by the leader spacecraft,a distributed containment control algorithm is designed for follower spacecraft.Moreover,to reduce the dependence of the designed control algorithms on the graph information and increase system robustness,the control gains are changing adaptively and the parametric uncertainties are handled,respectively.Finally,simulation results are provided to illustrate the effectiveness of the theoretical results.

关键词： Adaptive gain technique Distributed control Formation-containment Formation control Spacecraft formation flying

Transonic wing stall of a blended flying wing common research model based on DDES method

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Chinese Journal of Aeronautics 2016年第6期29卷 1506-1516页

作者： Tao Yang Li Yonghong Zhang Zhao Zhao Zhongliang Liu Zhiyong State Key Laboratory of Aerodynamics China Aerodynamics Research and Development Center High Speed Aerodynamic Institute China Aerodynamics Research and Development Center

Numerical simulation of wing stall of a blended flying wing configuration at transonic speed was conducted using both delayed detached eddy simulation(DDES) and unsteady Reynolds-averaged Navier-Stokes(URANS) equations methods based on the shear stress transport(SST) turbulence model for a free-stream Mach number 0.9 and a Reynolds number 9.6 × 106. A joint time step/grid density study is performed based on power spectrum density(PSD) analysis of the frequency content of forces or moments, and medium mesh and the normalized time scale0.010 were suggested for this simulation. The simulation results show that the DDES methods perform more precisely than the URANS method and the aerodynamic coefficient results from DDES method compare very well with the experiment data. The angle of attack of nonlinear vortex lift and abrupt wing stall of DDES results compare well with the experimental data. The flow structure of the DDES computation shows that the wing stall is caused mainly by the leeward vortex breakdown which occurred at x/xcr= 0.6 at angle of attack of 14°. The DDES methods show advantage in the simulation problem with separation flow. The computed result shows that a shock/vortex interaction is responsible for the wing stall caused by the vortex breakdown. The balance of the vortex strength and axial flow, and the shock strength, is examined to provide an explanation of the sensitivity of the breakdown location. Wing body thickness has a great influence on shock and shock/vortex interactions, which can make a significant difference to the vortex breakdown behavior and stall characteristic of the blended flying wing configuration.

关键词： Delayed detached eddy simulation flying wing Vortex lift Vortex breakdown Wing stall

A Trot and flying Trot Control Method for Quadruped Robot Based on Optimal Foot Force Distribution

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Journal of Bionic Engineering 2019年第4期16卷 621-632页

作者： Teng Chen Xiaobo Sun Ze Xu Yibin Li Xuewen Rong Lelai Zhou Center for Robotics School of Control Science and EngineeringShandong UniversityJinan 250061China

In order to enhance the dynamic motion capability of the bionic quadruped robot,a flying trot gait control method based on full-scale virtual model and optimal plantar force distribution is proposed.A stable flying trot gait is accomplished by mapping the robot torso motion to the foot trajectory.The force distribution calculated by the torso virtual model is converted into a quadratic optimization problem and solved in real time by the open source library Gurobi.The transition between the trot gait and the flying trot gait is achieved by coordinating leg motion phases.The results of the dynamic simulation verify that the proposed method can realize the 3D stable flying trot gait.Compared against the trot gait,the flying trot gait can improve the speed of the quadruped robot.Combine the trot gait and the flying trot gait,the quadruped robot can move efficiently and adapt to complex terrains.

关键词： quadruped robot flying trot virtual model control quadratic optimization

Fishing Ground Distribution of Neon flying Squid (Ommastrephes bartramii) in Relation to Oceanographic Conditions in the Northwest Pacific Ocean

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Journal of Ocean University of China 2017年第6期16卷 1157-1166页

作者： YU Wei CHEN Xinjun YI Qian College of Marine Sciences Shanghai Ocean University Shanghai 201306 P. R. China National Engineering Research Center for Oceanic Fisheries Shanghai Ocean University Shanghai 201306 P. R. China Key Laboratory of Sustainable Exploitation of Oceanic Fisheries Resources Ministry of Education Shanghai Ocean University Shanghai 201306 P. R. China Collaborative Innovation Center for Distant-water Fisheries Shanghai Ocean University Shanghai 201306 P. R. China

Neon flying squid, Ommastrephes bartramii, is a squid species of the North Pacific Ocean, which plays an important economical role in the international fishery. Logbook data for Chinese squid-jigging fishery over 2004–2011 were used to evaluate the relationship between the fishing grounds of the squid and the convergent frontal areas, which were defined by the contour lines of specific sea surface temperature(SST) and chlorophyll-a(Chl-a) concentration. Our results indicate that the SST in the range of 15 to 19℃ and the Chl-a concentration in the range of 0.1 to 0.4 mg m^(-3) are the favorable conditions for the aggregation of the squid. Additionally, we deduced that the SST at 17.5℃ and the Chl-a concentration at 0.25 mg m^(-3) are the optimal environmental conditions for the aggregation of O. bartramii. In August, the annual CPUE is positively correlated with the proportion of the fishing grounds with favorable SST and Chl-a concentration, as well as the combination of the two variables, implying that the abundance of the squid annually is largely depending on the presence of the favorable environmental conditions for fishery in August. Minor spatial difference between mean latitudinal location of the 17.5℃ SST and 0.25 mg m^(-3) Chl-a fronts can increase the CPUEs of O. bartramii. Furthermore, the monthly latitudinal gravity centers of the CPUE closely followed the mean latitudinal position of the contour lines of the 17.5℃ SST and the 0.25 mg m^(-3) Chl-a concentration. Our findings suggest the convergent oceanographic features(fronts) play significant roles in regulating the distribution and abundance of the western stock of the winter-spring cohort of O. bartramii, which can help people to improve their ability to discover the O. bartramii fishing grounds with higher productivity.

关键词： neon flying squid sea surface temperature chlorophyll-a oceanic fronts fishing ground the Northwest Pacific Ocean

Focus characteristics of long distance flying optics

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Science China Mathematics 2000年第9期43卷 980-987页

作者：程兆谷蒋金波李现勤许国良夏金安 W.M.Steen G.Dearden Shanghai Institute of Optics and Fine Mechanics Chinese Academy of Sciences Shanghai 201800 China Department of Mechanical Engineering University of Liverpool Liverpool L69.3BX UK

The ABCD law for the complex parameter q of the TEM00 Gaussian beam is generally not valid for high-order modes. It can be used for the high-order modes or their superposition when the spot size w in the virtual part of the parameter q is substituted by the Rayleigh range ZR of a certain resonator. The focus characteristics of long distance flying optics are studied in this paper theoretically and experimentally for the TEMmn Gaussian beams between the two types of resonators without and with distortion. It is very important for the applications of the flying optical processing, the laser space craft and the spatial filter in the large laser project.

关键词： flying optics Rayteigh range ABCD law focus characteristics.

The use of artificial nest boxes by Siberian flying squirrels (Pteromys volans) in South Korea

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Journal of Forestry Research 2019年第3期30卷 1131-1137页

作者： Jong-U Kim Woo-shin Lee Eun-Jae Lee Department of Forest Sciences Seoul National University Seoul 08826Republic of Korea Urban Planning Research Division Daejeon Sejong Research InstituteDaejeon 34863Republic of Korea

In this study, we examined the use of artificial nest boxes by Siberian flying squirrels (Pteromys volans) in three coniferous and mixed forests in Gangwon Province, South Korea. Six hundred and twelve boxes with different sized entry holes (ranging from 3 to 7 cm in diameter) were placed in the forests between 2004 and 2009. Pteromys volans used nine boxes in the coniferous forests and two boxes in the mixed forests. The squirrels only used boxes with entrance holes measuring 3.5, 4, and 5 cm in diameter, showing a strong and moderate preference for boxes with 5 and 4-cm holes, respectively, and a strong avoidance for boxes with 3- and 7-cm holes. Therefore, we suggest placing artificial nest boxes with entrance holes 5 cm in diameter to encourage breeding activity. Most nests made in the artificial boxes were composed of fibrous materials from woody vines. We recommend placing artificial nest boxes with holes of 5-cm diameter in coniferous forests, which support dense populations of P. volans, to survey whether this approach would positively affect the breeding habits and population maintenance of this species.

关键词： Artificial nest box Coniferous forests Nest materials Siberian flying squirrel Woody vines

Relative Attitude Dynamics and Control of Spacecraft Formation flying Considering Flexible Panels

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Journal of Shanghai Jiaotong university(Science) 2018年第6期23卷 721-729页

作者：余章卫蔡国平 Department of Engineering Mechanics State Key Laboratory of Ocean Engineering Shanghai Jiao Tong University

As a key technology for orbital applications, researches on spacecraft formation flying(SFF) attract more attention. However, most of existing researches about dynamics and control of SFF focus on rigid spacecrafts without considering the effect of flexible attachments(such as flexible panels). In this paper, relative attitude dynamics and active control of SFF for a flexible spacecraft(follower spacecraft) and a rigid spacecraft(target spacecraft) are investigated. Firstly, a dynamic model of the flexible spacecraft is established by the principle of angular momentum. Then, the equation of relative attitude dynamics between the flexible spacecraft and the rigid spacecraft is derived by the quaternion to represent the attitude relation of the two spacecrafts. Finally,an attitude feedback controller is designed for the SFF system, and its stability is proved by the Lyapunov stability theory. Simulation results indicate that the panel flexibility has an obvious influence on the dynamic behaviour of the system, the designed controller can effectively control the attitude of the two spacecrafts to achieve synchronization, and the elastic vibration of the panels may be suppressed simultaneously.

关键词： spacecraft formation flying (SFF) relative attitude dynamics flexible panel active control

Reliability Design of an Electronic Cam Curve for flying Shear Machine in Short Materials Cutting

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Journal of Shanghai Jiaotong university(Science) 2020年第2期25卷 246-252页

作者：毕俊喜樊文泽黄洪钟刘斌 School of Mechanical Engineering Inner Mongolia University of TechnologyHohhot 010051China College of Aviation Inner Mongolia University of TechnologyHohhot 010051China Institute of Reliability Engineering University of Electronic Science and Technology of ChinaChengdu 611731China

The structure and the production process for flying shear machine are introduced first.Then,a quintic polynomial is applied to the design of an electronic cam system for the rotary knife axis in short materials cutting.The dimensionless equation for a quintic polynomial cam curve is deduced.Finally,the curve is plotted with the cam constructor integrated into Siemens engineering development software SCOUT and it is tested with a laboratory platform,which consists of a motion controller SIMOTION and motor drivers SINAMICS S120.The results show that the running stability of the flying shear machine and the position control accuracy of the rotary knife can be effectively improved by using the curve designed in this paper.

关键词： flying shear machine electronic cam curve quintic polynomial SIMOTION non-dimensionalization