检索结果-南通市图书馆

Analytical geometry method of planetary gear trains

在线全文

学校读者我要写书评

暂无评论

Science China(Technological Sciences) 2012年第4期55卷 1007-1021页

作者： chen xiaoan chen Hong State Key Laboratory of Mechanical Transmissions Chongqing UniversityChongqing 400044China

This paper presents an analytical geometry method for kinematics and efficiency of planetary gear trains (PGTs). The novel method which is capable of evolution and contrast analysis of mechanism kinematics, can be applied to any typical one-and two-degree-of-freedom plane PGTs containing any number of simple, compound or complex-compound planetary gear sets. The efficiency analysis of this method features a systematized and programmed process and its independence of the speed ratio. The primary contribution of this work lies in the integration of quantitative calculation, qualitative evolution and comparative analysis of kinematics of PGTs into one diagram, and in the integration of kinematics and efficiency analysis into a single method system. First, the analytical geometry method is defined, its basic properties are given, and the systematization procedure to perform kinematic analysis is demonstrated. As an application, analytical geometry diagrams of common PGTs are exhibited in the form of a list, whose kinematic characteristics and general evolution tendency are discussed. Then, with the mapping of PGTs onto the angular speed plane, the efficiency formula of analytical geometry, which has an extremely concise form, and a simple method for power flow estimation are put forward. Moreover, a general procedure is provided to analyze the efficiency and power flow. Finally, four numerical examples including a complicated eleven-link differential PGTs are given to illustrate the simpleness and intuitiveness of the analytical geometry method.

关键词： analytical geometry planetary gear trains kinematics efficiency analysis method

Sputter Deposited Carbon Material based Fabry-Perot Sensor and Downhole Application

在线全文

学校读者我要写书评

暂无评论

Journal of Wuhan University of Technology(Materials Science) 2022年第6期37卷 1143-1149页

作者： WANG Yingying LIU Xiaohui chen xiaoan SUN Zhihui ZHAO Qingchao Laser Institute Qilu University of Technology(Shandong Academy of Sciences)Jinan 250103China School of Geophysics and Information Technology China University of Geosciences(Beijing)Beijing 100191China Logging Technology Research Institute China National Logging CorporationXi’an 710077China Shandong Computer Science Center Qilu University of Technology(Shandong Academy of Sciences)Jinan 250014China

To prevent hydrogen-induced loss and achieve long-term effective parameters monitoring in harsh downhole environment,we proposed a Fabry-Perot sensor with vacuum sputter deposited carbon coating film,in which we employed a deposition technology with a higher particle kinetic energy,closer substrate adhesion,and denser films,to deposit the coating film on the surface of the quartz capillary glass tube to protect the sensor from *** sensitivity and accuracy of the Fabry-Perot sensor with carbon film deposition can reach 369 nm/MPa and 0.02%FS,***,the sensor has less hysteresis error and good pressure linearity of more than 0.99999 for repeatable pressure *** downhole practice monitoring data indicated that this fiber-optic sensor exhibited excellent performance and the sputter deposited carbon coating can effectively decrease hydrogen loss.

关键词： quartz substrate Fabry-Perot sensor vacuum sputtering carbon coating material

MULTI-AGENT COLLABORATIVE DESIGN SYSTEM MODEL BASED ON THE INTERNET AND EXPERIMENTS

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Mechanical Engineering 2001年第4期14卷 357-361页

作者： chen xiaoan, Zheng Xiaoguang, chen Bingkui (State Key Laboratory of Mechanical Transmission,Chongqing University) 重庆大学机械传动国家重点实验室重庆

Development of complicated products is a project of system engineering It involves extensive and complicated knowledge,design methods and auxiliary technology Various factors affect each other So,modern product development is a typical group problem with distributed and dynamic features It is apparent superiority to solve this problem with a multi agent system representing various knowledge domains Distributed artificial intelligence knowledge being used,the multi agent collaborative design system concept and model based on Internet environment are put forward The realizing method of product developing agents,interactive process among multi agents,and organization and implementing of the design project of the multi agent collaborative design system are discussed in detail Application examples are also presented.

关键词： Collaborative design Shared environment Multi agent system

Adaptive Control of Lower-Limb Exoskeletons for Walking Assistance Based on Inter-Joint Coordination

在线全文

学校读者我要写书评

暂无评论

Journal of Bionic Engineering 2024年第4期21卷 1775-1787页

作者： Chaoyang Li Lincong Luo Zhi Liu Tianchi chen Songxiang Liu Ye He xiaoan chen Lei Li Wei Tech Ang School of Mechanical Engineering Chongqing UniversityChongqing400044China Rehabilitation Research Institute of Singapore Singapore308232Singapore Department of Orthopedics Union HospitalTongji Medical CollegeHuazhong University of Science and TechnologyWuhan430022China School of Mechanical and Aerospace Engineering Nanyang Technological UniversitySingapore639798Singapore

Unilateral motor impairment can disrupt the coordination between the joints,impeding the patient’s normal *** assist such patients to walk normally and naturally,an adaptive control algorithm based on inter-joint coordination was proposed in this work for lower-limb *** control strategy can generate the reference trajectory of the affected leg in real time based on a motion coordination model between the joints,and adopt an adaptive controller with virtual windows to track the reference *** Short-Term Memory(LSTM)network was also adopted to establish the coordination model between the joints of both lower limbs,which was optimized by preprocessing angle information and adding gait phase *** the adaptive controller,the virtual windows were symmetrically distributed around the reference trajectory,and its width was adjusted according to the gait phase of the auxiliary *** addition,the impedance parameters of the controller were updated online to match the motion capacity of the affected leg based on the spatiotemporal symmetry factors between the bilateral *** LSTM coordination model demonstrated good accuracy and generality in the gait database of seven individuals,with an average root mean square error of 3.5 and 4.1 for the hip and knee joint angle estimation,*** further evaluate the control algorithm,four healthy subjects walked wearing the exoskeleton while additional weights were added around the ankle joint to simulate an asymmetric *** the experimental results,it was shown that the algorithm improved the gait symmetry of the subjects to a normal level while exhibiting great adaptability to different subjects.

关键词： Lower-limb exoskeleton Adaptive control Gait symmetry Inter-joint coordination Motion estimation

Effects of tillage practices on nutrient loss and soybean growth in red-soil slope farmland

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

International Soil and Water Conservation Research 2013年第3期1卷 49-55页

作者： Yang Jie Zheng Haijin chen xiaoan Shen Le Jiangxi Institute of Soil and Water Conservation Jiangxi Provincial Key Laboratory of Soil Erosion and PreventionNanchangChina

Field experiments were conducted to examine the effect of tillage practices on sediment and nutrient loss and soybean growth under natural rainfall *** tillage practices were applied:downslope ridge(check),downslope ridge+contour living hedgerow,and cross *** ridge tillage reduced surface runoff by 69%and sediment yield by 86%,compared to the check *** downslope ridge with a contour living hedgerow reduced surface runoff by 24%and sediment yield by 53%.Additionally,compared to the check plot,nutrient losses carried by runoff were reduced by over 68%and that carried in the sediment was reduced more than 85%in the cross ridge *** losses in runoff were reduced by 20%to 30%in the downslope ridge and contour living hedgerow plot and those carried in the sediment were reduced by 44%to 57%.Cross ridge tillage soybean yields exceeded those of the downslope ridge and downslope ridge+contour living hedgerow treatments by 16%-18%.Cross ridge tillage could contribute to the prevention sediment and nutrient loss and could improve crop yield,and thus it is recommended to be applied to mild slopes in the red soil region.

关键词： Red soil Slope farmland Tillage practices Nutrient loss Crop growth

Automatic Measurement of Two Dimensional Object

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

Wuhan University Journal of Natural Sciences 1998年第1期3卷 61-64页

作者： Sun xiaoan chen Shuzhen Chai Yaping Wu Zhibin Wuhan University College of Electronic Information Wuhan China (GRID:grid.49470.3e) (ISNI:***)

Some core techniques related with automatic measurement of two dimensional object are discussed. Two kinds of corner point detecting methods are given. Least square fitting is used for edge line fitting. Region selection for accurate measurement is proposed. Combined with image recognition, location and macro recording file, automatic measurement of two dimensional object is realized.

关键词： corner point line fitting macro recording

在线全文

学校读者我要写书评

暂无评论

非线性结构平稳随机过程数值仿真分析

机械强度 2008年第4期30卷 523-528页

作者：缪莹赟陈小安重庆大学机械传动国家重点实验室重庆400044

平稳随机过程数值仿真分析因结构高度非线性因素而成为平稳随机振动分析中的难点,通常采用振型叠加法,将非线性结构简化为线性结构进行平稳随机过程数值仿真分析。为克服这一难点,文中以某一非线性预应力结构为例,首先采用谐波叠加法,... 详细信息

平稳随机过程数值仿真分析因结构高度非线性因素而成为平稳随机振动分析中的难点,通常采用振型叠加法,将非线性结构简化为线性结构进行平稳随机过程数值仿真分析。为克服这一难点,文中以某一非线性预应力结构为例,首先采用谐波叠加法,将已知的频域内功率谱密度曲线转化为时域内的加速度曲线,然后通过中心差分法,对非线性结构进行平稳随机过程数值仿真分析,并对数值仿真分析中存在的关键性技术进行探讨。结果表明,对具有预应力的非线性结构,振型叠加法在一定程度上能够反映结构的动力学特性,但不能反映结构的非线性特性,而中心差分法能更精确地反映非线性结构在随机激励下的动力学特性。通过分析,文中针对非线性结构平稳随机过程数值仿真分析,提出一种综合振型叠加法和中心差分法的有限元分析方法,目的在于解决平稳随机过程数值仿真分析中结构的高度非线性因素,为高度非线性预应力结构的平稳随机过程数值仿真分析提供一种新思路。

关键词：随机振动非线性结构预应力数值仿真分析

在线全文

学校读者我要写书评

暂无评论

基于耦合模型的高速电主轴动态分析与优化

机械工程学报 2014年第11期50卷 93-100页

作者：刘俊峰陈小安重庆大学机械传动国家重点实验室重庆400044

为提高高速电主轴工况下的动态性能,建立一个电主轴热-电-机耦合动力学模型。该模型包含球轴承热机耦合模型、热模型和考虑电磁不平衡力(Unbalanced electromagnetic force,UEF)影响的转轴动力学模型等子模型,各子模型之间基于轴承配置... 详细信息

为提高高速电主轴工况下的动态性能,建立一个电主轴热-电-机耦合动力学模型。该模型包含球轴承热机耦合模型、热模型和考虑电磁不平衡力(Unbalanced electromagnetic force,UEF)影响的转轴动力学模型等子模型,各子模型之间基于轴承配置相互影响。确定系统主要设计参数(Design parameters,DVs),设计电主轴多场耦合动力学计算流程,在型号170MDl5Y20电主轴上进行相关试验对耦合模型和计算模型进行验证,并分析DVs对系统固有频率的灵敏度。理论和试验结果表明所建模型和能准确预测高速电主轴多场耦合动力学行为并揭示其耦合关系,此外获取了不同轴承配置下DVs对系统前两阶固有频率的灵敏度。

关键词：高速电主轴动态优化轴承配置固有频率

高速电主轴电动机—主轴系统的机电耦合动力学建模

在线全文

学校读者我要写书评

暂无评论

机械工程学报 2007年第12期43卷 160-165页

作者：孟杰陈小安合烨重庆大学机械传动国家重点实验室重庆400044

针对高速电主轴系统具有复杂机电系统的特点,提出对高速电主轴系统进行机电耦合分析的观点。提炼并归纳了高速电主轴系统中存在的多物理过程、多参数耦合现象,给出高速电主轴系统全局耦合关系的框图。通过分析高速电主轴电动机—主轴子... 详细信息

针对高速电主轴系统具有复杂机电系统的特点,提出对高速电主轴系统进行机电耦合分析的观点。提炼并归纳了高速电主轴系统中存在的多物理过程、多参数耦合现象,给出高速电主轴系统全局耦合关系的框图。通过分析高速电主轴电动机—主轴子系统的结构及其耦合情况,得到了该子系统的机电耦合关系框图,并建立其物理模型。基于机电系统分析动力学理论,采用变分原理法,应用拉格朗日方程建立电动机—主轴子系统的电压方程和机械运动方程,将两组方程联立得到与该子系统物理模型相对应的数学模型,导出子系统的动力学方程,为进一步研究高速电主轴系统的机电耦合动力学性能提供理论基础。

关键词：高速电主轴系统机电耦合电动机-主轴模型