基于人体运动仿真的自行车结构优化

为了使自行车具有良好的骑行性能、动力输出性能,自行车设计过程需要根据人体的身体特征对自行车结构进行优化.采用一种新颖的人机建模仿真软件——The Anybody Modeling System,建立了自行车-人体下肢耦合模型并进行动力学仿真,分析了自行车结构尺寸对人体骑行状态的影响,并对自行车结构的相关因素进行正交试验.针对特定人体尺寸,以人体骑行舒适性为客观评价指标.给出了自行车的结构优化参数.     

基于Anybody的自行车骑行运动仿真与试验分析

以人体肌肉疲劳程度为评价标准,基于人体生理学、人机工程学和仿真试验技术,研究一种自行车结构参数设计的有效方法。以某自行车厂生产的一款公路自行车为例,在Anybody生物力学软件环境下建立人-车耦合系统模型;通过肌电信号试验及心肺功能测试,对人-车耦合系统模型进行了试验验证,确保仿真系统可靠;借助验证后的仿真系统进行了一系列仿真试验,以人体下肢肌肉受力为主要研究对象,分析了相同骑行速度、负载下鞍座位置与人体肌肉受力之间的映射关系。结果表明:对于同一骑行者,自行车鞍座位置对于其肌肉受力值的影响很大,即对其疲劳程度影响很大。分析方法与结果为自行车车架结构设计提供了依据,为自行车设计提供了新思路。     

马行式健身运动自行车结构设计

目前普通自行车仅腿部肌肉得到充分锻炼,而全身其他部位参与活动程度较低。为解决该问题,提出马行式健身运动自行车的结构设计方案,有效整合了健身和骑行两大功能。通过分析骑行过程中的人机交互特征,对运动机构进行改进设计,对相关结构部件进行力学仿真。通过样机制作并进行测试,验证该设计方案可行。     

自行车制动能量回收控制系统的设计

针对自行车频繁制动损耗能量的问题,对自行车制动过程中能量流动情况、电机再生制动、锂电池充电展开研究,对自行车制动过程中能量损耗、电机再生制动控制策略进行了归纳,提出了一种基于STC15F2K60S2内核单片机的自行车制动能量回收控制系统,通过改装公路自行车,搭建具有该系统的试验样车,在不同骑行道路上选择不同制动模式进行制动试验。研究结果表明,该系统能够根据车速以及骑行者的意愿选用合理的制动模式,在考虑骑行安全的前提下充分回收制动能量,明显提高了自行车的能源效率。     

电动自行车结构强度影响因素分析

为了对电动自行车车架进行结构改进,并分析其结构强度的影响因素,对企业提供的两款电动自行车车架进行了三维实体建模;进行人体动作捕捉、人体生物力学建模及骑行仿真试验,获得了骑行过程中施加于电动自行车车架的载荷;以所获载荷对电动车车架进行加载,对车架的ANSYS有限元进行分析,从而校核了车架疲劳强度及静强度,然后在此基础上对电动车车架结构进行了改进,并分析了电动自行车车架强度的影响因素。该结构改进提高了材料的使用效率,并保证了电动车车架的结构强度。     

基于CATIA的电动自行车人机工程设计

根据人机工程学的理论与方法,将人体特征数据应用于电动自行车的初始设计,分析了电动车各部件位置尺寸与人体尺寸之间的关系。利用CATIA软件建立符合中国人体特征数据的人体模型,通过对人体模型推行与骑行姿态的研究和优化,改善了电动自行车车把与鞍座之间的位置尺寸;通过对曲柄蹬踏机构的分析改进,提高了电动自行车的骑行效率;通过对骑行者视野的分析,确保所设计的电动自行车符合视野要求。总之,使改进后的电动自行车更加适合目标人群的尺寸特征和动作习惯。     

新型可升降坐垫自行车设计和研究

为了改善自行车骑行的舒适度,对传统自行车关键性结构坐垫进行了创新设计。针对目前市场上自行车坐垫无法调整或调整困难的尴尬局面,运用机械原理等,设计了一种可调节坐垫高低的新型自行车。设计结果表明该款自行车结构可行,应力分析安全可靠,符合消费者的需求。     

基于设计条件的自行车检测标准研究

针对目前自行车检测标准与自行车设计及其实际应用条件不相符的问题,通过对不同用途自行车的检测标准、不同使用条件自行车的检测标准、考虑骑行舒适性的自行车检测标准的探讨,提出了应基于设计条件,制定更加合理的自行车检测标准的建议。针对不同用途和使用条件的自行车,检测标准应该依据其实际受载情况进行加载检测,以便达到检测与实际应用相一致的目的,减少使用中出现事故的概率,而设计条件是制定检测标准的重要依据。从以人为本的角度出发,应该将骑行舒适性指标纳入自行车的检测标准,以提高自行车的品质,达到利于骑行者健康的目的。     

一种新型健身车的结构设计与有限元分析

为解决现有健身车运用于虚拟现实游戏时车身姿态无法变化的问题,根据自行车实地骑行时的车身姿态变化特点,设计了能模拟自行车实地骑行时,适应坡度、弯道和路面颠簸的车身前后俯仰、左右侧倾运动机构,该结构具有运动自适应特性。采用人机工程学方法对健身车进行设计,确定了车身结构和尺寸参数。运用有限元法对车身结构的6种极限位置姿态进行了受力分析,结果表明车身结构强度合格,该结构设计及其分析方法可为相关运动产品的设计提供参考。     

动态仿真技术在山地自行车设计中的应用

分析了采用双弹簧减振元件的某型山地自行车在骑行过程中后悬架机构出现异常的现象,并找出了原因.同时采用正交试验方法,应用动态分析与仿真软件ADAMS(Automatic Dynamic Analysis of Mechnical System)再现了机构运动状态,并给出了在一定负载条件下双弹簧连接件的结构尺寸与弹簧刚度间的匹配关系,以及不同匹配条件下山地车所能承受的最大载荷.同时,结合国标ISO2631-1中人体对振动反应的评价标准,得到了该车型在给定不同设计条件下的骑行舒适性相对指标,为该车型设计参数及零部件的合理选择提供了理论依据.     

Minimal Realization of Linear Graph Models for Multi-physics Systems

An engineering system may consist of several different types of components,belonging to such physical"domains"as mechanical,electrical,fluid,and thermal.It is t...     

Quantum Cooperative Robotics and Autonomy

The intersection of Quantum Technologies and Robotics Autonomy is explored in the present paper.The two areas are brought together in establishing an interdisci...     

考虑进油孔有限长滑动轴承油膜力的近似解析解

针对具有进油孔的有限长滑动轴承油膜力求解问题,采用变分原理和分离变量法,求得了有限长滑动轴承油膜压力分布的近似解析表达式。将油膜压力分布的近似解析表达式在油膜存在区域上进行积分,即得到了油膜力。将提出的计算有限长滑动轴承油膜力方法与无限长轴承模型、有限元方法的计算结果进行了比较,发现了提出的方法与有限元方法的计算结果很接近。最后,研究了进油孔位置和进油压力对油膜存在区域、油膜力等的影响,研究结果表明进油孔位置和进油压力对油膜存在区域和油膜力有较大的影响。     

三绕组变压器的双绕组等效建模及在Matpower中的应用

针对实际电网存在着大量的三绕组变压器,但国际上一些著名商业软件,如BPA仿真软件、Matpower这一权威潮流计算开源软件,均只提供双绕组变压器模型,限制了其在具有三绕组变压器的电力系统中的应用的问题,潮流计算是自主开发的电力系统各种应用软件的核心模块,因此依托国际权威开源程序进行二次开发,是一种较好的选择。对Matpower要求的数据格式进行了归纳,对变压器的一般的等值电路及带理想变压器的等值电路和带标幺值的等值电路进行了分析研究,提出了三绕组变压器转换为双绕组等效模型的建模方法,使得原先只适应双绕组变压器的潮流计算软件可以适用于三绕组变压器电网的潮流计算;最后以Matpower软件为例进行了案例计算,并用PSASP仿真软件进行对比验证。研究结果证明,所提出的建模方法是有效的。     

On the Relation of Load to Average Gap in the Contact Between Surfaces with Longitudinal Roughness

A computer simulation model for the contact between longitudinally-oriented rough surfaces has been formulated. This model closely duplicates the actual surf ace contact deformation behavior by taking into account the elastic interactions between the asperities. There were no assumptions made about the shapes, or any deformation behavior of the asperities, except for their obeying the laws of elasticity. The plastic deformations on the high asperity peaks were taken into account by setting a ceiling on their contact pressures at the material hardness value. The simulations used real surface profiles which were digitized from unworn circumferentially ground steel surfaces. Each pair of these profiles was mathematically combined to form an equivalent rough profile pressing against an infinitely rigid flat and having the appropriately adjusted elastic modulus. A total of 28 different pairs of profiles were used in the simulations. Each contacting pair was subjected to 30 different load levels and the local contact pressures and deformations were calculated. The contact simulations yielded some important mathematical relationships between parameters, such as the real area of contact, average gap, and average asperity load through statistical curve fitting. Two analytical functions were generated to relate the average load to average gap and the real area of contact to load.     

INTEGRAL EQUATION METHOD＇S APPLICATION IN HOLE-EDGE STRESS OF COMPOSITE MATERIAL PLATE WITH DIFFERENT SHAPED HOLES

The strength of composite plate with different hole-shapes is always one of the most important but complicated issues in the application of the composite material. The holes will lead to mutations and discontinuity to the structure. So the hole-edge stress concentration is always a serious phenomenon. And the phenomenon makes the structure strength decrease very quickly to form dangerous weak points. Most partial damage begins from these weak points. According to the complex variable functions theory, the accurate boundary condition of composite plate with different hole-shapes is founded by conformal mapping method to settle the boundary condition problem of complex hole-shapes. Composite plate with commonly hole-shapes in engineering is studied by several complex variable stress fimction. The boundary integral equations are founded based on exact boundary conditions. Then the exact hole-edge stress analytic solution of composite plate with rectangle holes and wing manholes is resolved. Both of offset axis loadings and its influences on the stress concentration coefficient of the hole-edge are discussed. And comparisons of different loads along various offset axis on the hole-edge stress distribution of orthotropic plate with rectangle hole or wing manhole are made. It can be concluded that hole-edge with continuous variable curvatures might help to decrease the stress concentration coefficient; and smaller angle of outer load and fiber can decrease the stress peak value.     

电站锅炉模糊风险评价方法研究与应用

针对电站锅炉风险等级评价问题,将模糊综合评价技术应用到电站锅炉风险等级评价中。开展了电站锅炉失效影响因素及模糊评价因素的重要程度分析,建立了一套科学合理适于在线评价的电站锅炉风险评价体系,提出了模糊综合评价技术与改进的模糊层次分析法相结合的模糊风险评价方法,利用改进的模糊层次分析法计算了指标体系中各层指标权重。对某一台电站锅炉的实际运行工况影响子因素进行了模糊风险评价,采用模糊合成算子进行模糊综合运算得到电了站锅炉运行工况影响子因素的评价向量。研究结果表明:电站锅炉的运行工况影响子因素的风险评价等级为第6级,失效可能性等级为小,该电站锅炉运行工况良好。     

Short-Term Relay Quality Prediction Algorithm Based on Long and Short-Term Memory

The fraction defective of semi-finished products is predicted to optimize the process of relay production lines, by which production quality and productivity ar...     

End-to-End Multiview Gesture Recognition for Autonomous Car Parking System

The use of hand gestures can be the most intuitive human-machine interaction medium.The early approaches for hand gesture recognition used device-based methods....     

Non-monotonic material contrast in scanning ion and scanning electron images

30 keV Ga⁺ focused ion beam induced secondary electron (iSE) imaging was used to determine the relative contrast between several materials. The iSE signal compared from C, Si, Al, Ti, Cr, Ni, Cu, Mo, Ag, and W metal layers does not decrease with an increase in target atomic number Z₂, and shows a non-monotonic relationship between contrast and Z₂. The non-monotonic relationship is attributed to periodic fluctuations of the stopping power and sputter yield inherent to the ion–solid interactions. In addition, material contrast from electron-induced secondary electron (eSE) and backscattered electron (BSE) images using scanning electron microscopy (SEM) also shows non-monotonic contrast as a function of Z₂, following the periodic behavior of the stopping power for electron–solid interactions. A comparison of the iSE and eSE results shows similar relative contrast between the metal layers, and not complementary contrast as conventionally understood. These similarities in the contrast behavior can be attributed to similarities in the periodic and non-monotonic function defined by incident particle–solid interaction theory.