检索结果-南通市图书馆

Chinese Journal of Aeronautics 2024年第3期37卷 417-439页

作者： Dongyang shang Xiaopeng LI Meng YIN Fanjie LI School of mechanical engineering and automation Northeastern UniversityShenyang 110819China Shenzhen Institute of Advanced Technology Chinese Academy of SciencesShenzhen 518055China

In space operation,flexible manipulators and gripper mechanisms have been widely used because of light weight and ***,the vibration caused by slender structures in manipulators and the parameter perturbation caused by the uncertainty derived from grasping mass variation cannot be *** existence of vibration and parameter perturbation makes the rotation control of flexible manipulators difficult,which seriously affects the operation accuracy of ***’s more,the complex dynamic coupling brings great challenges to the dynamics modeling and vibration *** solve this problem,this paper takes the space flexible manipulator with an underactuated hand(SFMUH)as the research *** dynamics model considering flexibility,multiple nonlinear elements and disturbance torque is established by the assumed modal method(AMM)and Hamilton’s principle.A dynamic modeling simplification method is proposed by analyzing the nonlinear ***’s more,a sliding mode control(SMC)method combined with the radial basis function(RBF)neural network compensation is ***,the control law is designed using a saturation function in the control method to weaken the chatter *** the help of neural networks to identify the uncertainty composition in the SFMUH,the tracking accuracy is *** results of ground control experiments verify the advantages of the control method for vibration suppression of the SFMUH.

关键词： Space flexible manipulator RBF neural network Underactuated hand Dynamic models Model simplification

EA模型在海洋的速度横向时空互相关函数中的应用

在线全文

学校读者我要写书评

暂无评论

Acta Mechanica Sinica 2024年第3期40卷 54-60页

作者：梁长荣尚晓东陈桂英何晓舟童彭尔 State Key Laboratory of Tropical Oceanography South China Sea Institute of OceanologyChinese Academy of SciencesGuangzhou510301China School of mechanical engineering and automation Harbin Institute of Technology(Shenzhen)Shenzhen518055China Department of Physics Hong Kong University of Science and TechnologyHong KongChina

椭圆近似(EA)模型是从单个点的时间波动数据中推断空间波动数据的重要方法,它已在室内实验剪切场的纵向时空互相关函数C(r,τ)得到验证并被广泛应用.在这里,我们研究了EA模型在海洋流场中的有效性,并介绍了其在横向时空互相关函数G(r,τ... 详细信息

椭圆近似(EA)模型是从单个点的时间波动数据中推断空间波动数据的重要方法,它已在室内实验剪切场的纵向时空互相关函数C(r,τ)得到验证并被广泛应用.在这里,我们研究了EA模型在海洋流场中的有效性,并介绍了其在横向时空互相关函数G(r,τ)中的应用.结果表明,EA模型在海洋的速度场中是有效的,即G(r,τ)具有G(r_(E),0)的尺度形式,其中r_(E)=[(r-Uτ)^(2)+(Vτ)^2]^(1/2),U和V是与内波垂直相速度相关的两个特征速度.基于EA模型,我们可以获得海洋的垂直波数能谱,并估计海洋的泰勒微尺度和雷诺数.

关键词： Elliptical approximation model Spatial fluctuations Temporal fluctuations Space-time cross-correlation functions Taylormicro-scale

Rotation Angle Control Strategy for Telescopic Flexible Manipulator Based on a Combination of Fuzzy Adjustment and RBF Neural Network

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Journal of mechanical engineering 2022年第4期35卷 203-226页

作者： Dongyang shang Xiaopeng Li Meng Yin Fanjie Li Bangchun Wen School of mechanical engineering and automation Northeastern UniversityShenyang 110819China Shenzhen Institutes of Advanced Technology Chinese Academy of SciencesShenzhen 518055China

The length of fexible manipulators with a telescopic arm alters during *** dynamic parameters of telescopic fexible manipulators exhibit signifcant time-varying characteristics owing to variations in *** an increase in the manipulators’length,the nonlinear terms caused by fexibility in the manipulators’dynamic equations cannot be *** time-varying characteristics and nonlinear terms of telescopic fexible manipulators cause fuctuations in rotation angles,which afect the operation accuracy of *** this study,a control strategy based on a combination of fuzzy adjustment and an RBF neural network is utilized to improve the control accuracy of fexible telescopic ***,the dynamic equation of the manipulators is established using the assumed mode method and Lagrange’s principle,and the infuence of nonlinear terms is ***,a combined control strategy is proposed to suppress the fuctuation of the rotation angle in telescopic fexible *** variation ranges of the feedforward PD controller parameters are determined by the pole placement strategy and length of the *** rules are utilized to adjust the controller parameters in *** RBF neural network is utilized to identify and compensate the uncertain part of the dynamic model of the fexible *** uncertain part comprises time-varying parameters and nonlinear ***,numerical simulations and prototype experiments prove the efectiveness of the combined control *** results prove that the proposed control strategy has a smaller standard deviation of ***,the combined control strategy is more suitable for telescopic fexible manipulators,which can efectively improve the control accuracy of rotation angles.

关键词： Flexible manipulator RBF neural network Fuzzy control Dynamic uncertainty

Emotion-Aware Music Driven Movie Montage

在线全文

学校读者我要写书评

暂无评论

Journal of Computer Science & Technology 2023年第3期38卷 540-553页

作者：刘伍琴林敏轩黄海斌马重阳宋玉董未名徐常胜 School of Artificial Intelligence University of Chinese Academy of SciencesBeijing 101408China The State Key Laboratory of Multimodal Artificial Intelligence System(MAIS) Institute of AutomationChinese Academy of SciencesBeijing 100190China Kuaishou Technology Beijing 100085China School of mechanical engineering University of Science and Technology BeijingBeijing 100083China

In this paper, we present Emotion-Aware Music Driven Movie Montage, a novel paradigm for the challenging task of generating movie montages. Specifically, given a movie and a piece of music as the guidance, our method aims to generate a montage out of the movie that is emotionally consistent with the music. Unlike previous work such as video summarization, this task requires not only video content understanding, but also emotion analysis of both the input movie and music. To this end, we propose a two-stage framework, including a learning-based module for the prediction of emotion similarity and an optimization-based module for the selection and composition of candidate movie shots. The core of our method is to align and estimate emotional similarity between music clips and movie shots in a multi-modal latent space via contrastive learning. Subsequently, the montage generation is modeled as a joint optimization of emotion similarity and additional constraints such as scene-level story completeness and shot-level rhythm synchronization. We conduct both qualitative and quantitative evaluations to demonstrate that our method can generate emotionally consistent montages and outperforms alternative baselines.

关键词： movie montage emotion analysis audio-visual modality contrastive learning

Vertical multiple-layer structure of temperature and turbulent diffusivity in the South China Sea

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Acta Oceanologica Sinica 2022年第10期41卷 14-21页

作者： Xin He Changrong Liang Yang Yang Guiying Chen Xiaodong shang Xiaozhou He Penger Tong State Key Laboratory of Tropical Oceanography South China Sea Institute of OceanologyChinese Academy of SciencesGuangzhou510301China university of Chinese academy of Sciences Beijing100049China Southern Marine Science and engineering Guangdong Laboratory(Guangzhou) Guangzhou511458China Institution of South China Sea Ecology and Environmental engineering Chinese Academy of SciencesGuangzhou510301China Institute of Deep-Sea Science and engineering Chinese Academy of SciencesSanya572000China School of mechanical engineering and automation Harbin Institute of TechnologyShenzhen518055China Department of Physics Hong Kong University of Science and TechnologyHong Kong999077China

We report field measurements of vertical profiles of the turbulent diffusivity and temperature at different stations in the South China Sea(SCS).Our study shows that the measured turbulent diffusivity follows a power-law distribution with a varying exponent in water *** multiple-layer scaling regimes were also observed from the temperature *** turbulent diffusivity and temperature fluctuations,the vertical structure of temperature was ***,we discussed the temperature profiles in each layer.A constant function of a dimensionless temperature profile was found in water layers that have identical turbulence *** results reveal the multiple-layer structure of temperature in the *** study contributes to the understanding of the vertical structure of multiple layers in the SCS and provides clues for exploring the physical mechanism for maintaining the temperature structure.

关键词： temperature profile turbulent diffusivity South China Sea multiple layers

Primary Study on Crop Wet Biomass Measuring with Dielectric Spectroscopy

在线全文

学校读者我要写书评

暂无评论

Primary Study on Crop Wet Biomass Measuring with Dielectric ...

An Effective On-line Surface Particles Inspection Instrument for Large Aperture Optical Element

The 2010 International Conference on Manufacturing Science and Materials engineering(ICMSME 2011)

作者： Hua Zhang Baiyu Wu Ruifeng Hou Dazhou Zhu Dayu Pan Kun Bi Cheng Wang mechanical engineering and automation academy of shang hai university National Research Center of Intelligent Equipment for Agriculture

Crop wet biomass measuring with dielectric spectroscopy is a non-destructive method to quickly and accurately estimate plant biomass in situIt optimizes the management of agronomistsAn electrostatic free-space system was designed and tested to estimate crop wet biomass in situIt acts as a parallel plate capacitorThe appropriate size of plate of the system is determined through Finite element analysis（FEA）Water is used to make the exclusion of interference at the earlier stage of the experiment, and Wheat is the experiment materialResults from the measuring system showed The Susceptance through the system was strongly correlated with wet biomassThe coefficient of determination（r2） is greater than 0.9.

关键词： biomass dielectric spectroscopy Finite element analysis(FEA).Free-space antennae

来源： cnki会议评论

在线全文

cnki会议

学校读者我要写书评

暂无评论

International Journal of automation and computing 2017年第4期14卷 420-431页

作者： Wen-Dong Ding Zheng-Tao Zhang Da-Peng Zhang De Xu hai-Bing Lv Xin-Xiang Miao Guo-Rui Zhou Hao Liu Research Center of Precision Sensing and Control Institute of Automation Chinese Academy of Sciences School of Computer and Control engineering University of Chinese Academy of Sciences Laser Fusion Research Center China Academy of Engineering Physics

Surface particles growing in large aperture optical element （LAOE） have significant impact on LAOE＇s stable operation. It is a challenge for the online system to inspect the particles with long working distance, enough precision and high efficiency because of the system constraints. In this paper, an effective and portable inspection instrument is designed based on dark-field imaging principle. A Nikon lens and an industrial high definition （HD） camera are selected to construct the vision system to inspect particles of microns size spreading over hundreds of millimeters. Using two motors and other mechanical structure, the system can realize auto-focus and image rectification functions. The line light sources are installed on both sides of the LAOE in a sealed box while the vision system is portable and working outside the box. An adaptive binarization method is proposed to process the captured dark-field image. The distribution of particles on the LAOE＇s surface is investigated. Because of the high resolution of the captured image, the SSE2 instructions optimization method is used to reduce the time cost of the algorithm. Experiments show that the instrument can inspect LAOE effectively and accurately.

关键词： Dark-field imaging image rectification adaptive binarization particle inspection large aperture optical elements(LAOE).

Influence of in-flight particle characteristics and substrate temperature on the formation mechanisms of hypereutectic Al-Si-Cu coatings prepared by supersonic atmospheric plasma spraying

在线全文

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2021年第28期87卷 216-233页

作者： Peng-fei He Guo-zheng Ma hai-dou Wang Ling Tang Ming Liu Yu Bai Yu Wang Jian-jiang Tang Dong-yu He hai-chao Zhao Tian-yang Yu National Key Laboratory for Remanufacturing Army Academy of Armored ForcesBeijing 100072China School of mechanical engineering and automation Beihang UniversityBeijing100191China State Key Laboratory for mechanical Behavior of Materials Xi’an Jiaotong UniversityXi’an710049China State Key Laboratory of Electrical Insulation and Power Equipment Xi’an Jiaotong UniversityXi’an710049China School of Materials engineering Xi'an Aeronautical UniversityXi'an710077China

Hypereutectic Al-Si-Cu coatings were prepared by supersonic atmospheric plasma spraying to enhance the surface performance of lightweight *** find out optimum process conditions and achieve desirable coatings,this work focuses on the influence of three important parameters(in-flight particle temperature,impact velocity,and substrate temperature)on the collected splats morphology coatings microstructure and *** show that appropriate combinations of temperature and velocity of in-flight particles cannot only completely melt hypereutectic Al-Si-Cu particles especially the primary Si phase,but also provide the particles with sufficient kinetic ***,the optimized coating consists of 98.6%of fully-melted region with nanosized coupled eutectic and 0.9%of *** the substrate deposition temperature promotes the transition from inhomogeneous banded microstructure to homogeneous equiaxed microstructure with a lower porosity *** observations are further interpreted by a newly developed phase-change heat transfer model on quantitatively revealing the solidification and remelting behaviors of several splats deposited on substrate Besides,phase evolutions including the formation of supersaturatedα-Al matrix solid solution,growth of Si and Al_(2)Cu phases at different process conditions are *** ideal microstructure(low fractions of unmelted/partially-melted regions and defects)together with solid solution,grain refinement and second phase strengthening effects contributes to the enhanced microhardness of *** integrated study not only provides a framework for optimizing Al-Si based coatings via thermal spraying but also gives valuable insights into the formation mechanisms of this class of coating materials.

关键词： Thermal sprayed coatings Al-Si alloys In-flight particle characteristics Substrate temperature Process control

Predicting the evolution of photospheric magnetic field in solar active regions using deep learning

在线全文

学校读者我要写书评

暂无评论

Research in Astronomy and Astrophysics 2021年第5期21卷 109-120页

作者：白亮毕以杨波洪俊超徐喆尚振宏刘辉季海生季凯帆 Faculty of Information engineering and automation Kunming University of Science and TechnologyKunming 650500China Yunnan Observatories Chinese Academy of SciencesKunming 650216China Purple Mountain Observatory Chinese Academy of SciencesNanjing 210034China Yunnan Key Laboratory of Artificial Intelligence Kunming University of Science and TechnologyKunming 650500China

The continuous observation of the magnetic field by the Solar Dynamics Observatory(SDO)/Helioseismic and Magnetic Imager(HMI)produces numerous image sequences in time and *** sequences provide data support for predicting the evolution of photosphericmagnetic *** on the spatiotemporal long short-term memory(LSTM)network,we use the preprocessed data of photospheric magnetic field in active regions to build a prediction model for magnetic field *** of the elaborate learning and memory mechanism,the trained model can characterize the inherent relationships contained in spatiotemporal *** testing results of the prediction model indicate that(1)the prediction pattern learned by the model can be applied to predict the evolution of new magnetic field in the next 6 hours that have not been trained,and predicted results are roughly consistent with real observed magnetic field evolution in terms of large-scale structure and movement speed;(2)the performance of the model is related to the prediction time;the shorter the prediction time,the higher the accuracy of the predicted results;(3)the performance of themodel is stable not only for active regions in the north and south but also for data in positive and negative *** experimental results and discussions on magnetic flux emergence and magnetic neutral lines finally show that the proposed model could effectively predict the large-scale and short-term evolution of the photospheric magnetic field in active ***,our study may provide a reference for the spatiotemporal prediction of other solar activities.

关键词： methods:data analysis Sun:magnetic fields spatiotemporal prediction recurrent neural network

Rapid Optimization of Tension Distribution for Cable-Driven Parallel Manipulators with Redundant Cables

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of mechanical engineering 2016年第2期29卷 231-238页

作者： OUYANG Bo shang Weiwei Department of automation University of Science and Technology of China

The solution of tension distributions is infinite for cable-driven parallel manipulators（CDPMs） with redundant cables. A rapid optimization method for determining the optimal tension distribution is presented. The new optimization method is primarily based on the geometry properties of a polyhedron and convex analysis. The computational efficiency of the optimization method is improved by the designed projection algorithm, and a fast algorithm is proposed to determine which two of the lines are intersected at the optimal point. Moreover, a method for avoiding the operating point on the lower tension limit is developed. Simulation experiments are implemented on a six degree-of-freedom（6-DOF） CDPM with eight cables, and the results indicate that the new method is one order of magnitude faster than the standard simplex method. The optimal distribution of tension distribution is thus rapidly established on real-time by the proposed method.

关键词： cable-driven parallel manipulator tension distribution redundant cable linear programming