基于人机工程学的健骑机设计与仿真

健身器材这种与人密切相关的产品设计中，考虑人机工程学的设计理念更加重要。文章基于人机工程学和机械设计的理论和方法，设计了健骑机设计。确定了健骑机的主要尺寸参数，确定了踏板的闽距和倾角、座位的形状、把手的形状等。运用Pro/E软件对健骑机的主要零部件及整机装配图进行了三维建模。并运用其运动仿真功能对健骑机进行了分析。结果表明，设计是合理的。这种基于人机工程学和Pro/E软件的设计方法，可应用到其他产品的设计中。     

电动沙发八杆搁脚机构优化设计

针对电动沙发八杆搁脚机构运行过程中存在的平稳性较差问题,对搁脚杆系运动过程中的速度及传动角变化进行了研究。为提高搁脚机构杆件运动速度的平稳性,采用杆系运动学理论建立了八杆搁脚机构各运动杆件的位置、速度方程,通过Matlab运行了理论模型,然后与Adams中的运动仿真分析进行了对比,评价了理论模型的正确性;在理论模型的基础上,采用了遗传算法作为优化算法,以搁脚机构运行过程中速度的平稳性即速度波动性最小为目标,对搁脚机构的杆件尺寸进行了优化;将优化前后的模型参数输入到Adams中仿真分析并进行了比较,分析了优化结果。研究结果表明:优化后搁脚机构的速度平稳性得到了提升,同时搁脚机构的传动角也得到了相应的增加。     

单自由度八杆起背机构的设计与研究

为提高可分离式护理床椅的舒适性与稳定性，设计了一种新型单自由度八杆起背机构。首先，结合人机工程学，以背部滑移量及滑移速度为参数，验证了腰背结合型背板相比传统单板型背板的起背运动更加符合舒适性的要求；其次，建立起背机构的运动学模型，并基于Adams软件对机构进行参数化建模，分析了各部件对起背过程中背板最大角加速度变化的灵敏度，以背板角加速度最大值最小为目标对机构关键尺寸进行了优化；然后，根据优化结果，应用SolidWorks建立机构的三维模型，并使用Adams与Workbench联合仿真，验证了机构的强度合理性；最后，制作实物样机，验证了机构的可行性。     

某高功率密度减速器综合化优化设计方法

随着机械传动部件对功率密度要求的提高,以安全系数法和经验图表为基础的传统设计方法难以满足要求。文中针对某矿用高功率密度减速器,通过试算与论证改进其传动方案,基于Matlab优化方法优化了齿轮传动设计参数、基于斜齿轮接触线总长度变化量最小优化了螺旋角参数,并运用有限元方法对设计结果进行了辅助分析,从而实现该减速器的综合优化设计。与传统设计结果比较,缩减了23%的总质量和18%的径向体积尺寸,效果显著。     

基于混合离散方法的多级齿轮传动系统振动优化

综合考虑齿轮副啮合刚度、啮合阻尼和传动误差,基于集中参数法建立了多级齿轮传动六自由度纯扭转模型微分方程,采用谐波平衡法求解得到系统各部件的振动加速度;以所有部件的质量和振动加速度最小为优化目标函数,各级齿轮副的齿数、模数和螺旋角等为优化设计变量,齿轮强度、传动比和重合度等为约束条件,建立了多级齿轮传动系统振动优化模型。基于分支定界算法,在MATLAB中编写混合离散优化程序,求解得到最优的设计变量;进而对振动响应进行重分析,验证了优化效果。结果表明,优化后系统加速度平均值较优化前减小了33.5%,总质量较优化前减小了12.96%,优化效果较为显著。     

FASE赛车双叉臂悬架系统设计

根据FASE中国大学生方程式汽车大赛的规则和设计要求,本设计确定了赛车的轮距、质心高度、前轮主销后倾角等整车参数。采用双叉臂结构作为赛车悬架结构形式,利用CATIA和Adams软件对悬架的主要结构部件进行了三维建模和运动学仿真,通过性能分析和计算,优化了悬架结构设计,整车装配调试后的实际运行情况表明,所设计的双叉臂悬架结构具有较好的稳定性和操纵性。     

考虑部件失效相关的履带车辆传动箱可靠性分析

在以履带车辆传动箱为对象进行研究的过程中,考虑部件间失效相关这一重要失效形式对传动箱可靠性的影响,利用部件的动态可靠度模型计算主要失效部件的可靠度,结合部件寿命分布函数与可靠性间的关系,得到传动箱内主要部件的寿命分布函数随时间变化的曲线,进一步使用最小二乘法估算出主要零部件的寿命分布函数。在此基础上,绘制部件间的二元频率直方图,选择合适的Copula函数,建立在部件失效相关条件下的传动箱系统可靠性模型,利用Copula函数可以避免运算的繁琐性及部件间相关系数求解的复杂性。使用逐层分块分析法合理划分传动箱系统结构,并用Matlab软件估算部件间相关参数,得到了传动箱系统寿命分布函数随时间及部件失效相关参数的变化规律,对传动箱的设计与维护具有一定的指导意义。     

主轴部件静动态特性分析

随着加工中心产品不断向高精度、高刚度、高速度方向发展,对加工中心主轴部件的动态特性要求也越来越高,因此对加工中心产品主轴部件静、动态特性分析及其结构参数优化研究也显得越来越重要。１　主轴部件结构简介及梁单元模型建立　　图１是本课题研究的卧式加工中心主轴部件的结构简图。其中,主轴是一个多阶梯空心圆柱体,在主轴上面安装轴承组件、传动齿轮、轴承隔套、锁紧螺母等零件。轴承组件型号为ＳＫＦ７１３２ＡＣＤＰ４ＤＢＡ角接触向心推力球轴承。主轴部件前端部受切削力,后端受传动齿轮作用力。其端部安装各种刀具由拉刀…     

大学生方程式赛车悬架系统设计与仿真分析

按照FSAE赛事对赛车及悬架系统的设计要求,以整车基本参数和设计规则为参照依据,选定轮胎、轮辋型号,利用CATIA软件建立了FSAE赛车悬架系统的几何模型,对减震器、横向稳定杆等进行结构设计,利用Adams/Insight软件对轮胎跳动时悬架参数变化进行对比分析与优化,并运用ANSYS软件对悬架的主要受力部件进行分析。优化和仿真结果表明设计的悬架系统满足参赛要求,为后期赛车制造及调试提供理论依据。     

复合形法在凸轮优化设计中的应用

通过对圆弧同向传动凸轮机构的运动学分析,找出了原设计的缺陷,提出了改进措施,建立了圆弧同向传动凸轮廓线优化数学模型,利用复合形优化方法对其进行了优化设计计算。结果表明,优化后凸轮在传动过程中的压力角变化相对比较稳定,优化效果明显。     

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...     

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.     

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.     

Application of Feature Extraction through Convolution Neural Networks and SVM Classifier for Robust Grading of Apples

This paper proposes a novel grading method of apples,in an automated grading device that uses convolutional neural networks to extract the size,color,texture,an...     

分布动态载荷识别的抗噪处理

针对正交多项式频域法在用多种响应对矩形薄板进行载荷识别中抗噪性较差的问题,综合运用平均法、矩阵预处理和奇异值截断法等方法对之进行改善,并引入空间映射的思想,将该方法的应用范围拓展为复杂的模型.利用仿真算例,证实了该方法具有较好的抗噪性.     

基于MELTAC-N平台的核电厂安全级DCS环网研究与测试

针对工程实践中环网通讯相关问题的处理缺乏理论基础及国产化安全级DCS平台的开发缺乏成熟经验借鉴问题,对基于MELTAC-N平台核电厂安全级DCS环网的软硬件实现进行了研究。提出了安全级DCS环网双环网冗余设计、光切换开关设计等硬件设计方法,以及以RPR协议为基础,采用全数据收发策略的软件设计方法。在CPR1000安全级DCS平台上对安全级DCS环网的可靠性及实时性进行了评价,并进行了容错能力、响应时间及响应时间稳定性测试验证实验。结果表明,基于MELTAC-N平台安全级DCS环网软硬件设计具有较好的容错能力及响应时间稳定性。     

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....     

The laboratory simulation of abrasive wear

Abrasive wear has long been recognised as one of the most potentially serious tribological problems facing the operators of many types of plant and machinery; several industrial surveys have indicated that wear by abrasion can be responsible for more than 50% of unscheduled machine and plant stoppages. Locating the operating point of a tribological contact in an appropriate operational ‚map’︁ can provide a useful guide to the likely nature and origins of the surface degradation experienced in use, though care must be exercised in choosing the most suitable parameters for the axes of the plot. Laboratory testing of materials and simulations of machine contacts are carried out for a number of purposes; at one level for the very practical aims of ranking candidate materials or surface hardening treatments in order of their wear resistance, or in an attempt to predict wear lives under field conditions. More fundamentally, tests may be aimed at elucidating the essential physical mechanisms of surface damage and loss, with the longer term aim of building an analytical and predictive model of the wear process itself. In many cases, component surface damage is brought about by the ingress of hard, particulate matter into machine bearing or sealing clearances. These may be running dry although, more usually, a lubricant or service fluid is present at the interface. A number of standardised wear test geometries and procedures have been established for both two- and three-body wear situations, and these are briefly described. Although abrasive wear is often modelled as following an ‚Archard’︁ equation (i.e. a linear increase in material loss with both load and time, and an inverse dependence on specimen hardness) both industrial experience and laboratory tests of particularly lubricated contacts show that this is not always the case: increasing the hardness differential in an abrasively contaminated lubricated pair may not always reduce the rate of damage to the harder surface.     

ANGULAR DISTORTION ALLOWABLE VALUE AND ASSESS METHOD OF WELD ON COKE TOWER

A graph as the new engineering method for estimate the safety of bulging deformation of coke tower is proposed. Through stresses analysis of circumferential weld of coke tower and comparing the stresses produced by pressure with heat stress of steady state, residual stress, bending stress produced by both itself weight and wind loads, it showed that the stresses produced by pressure on the angle distortion are the main factor of equivalent stress of the combined stress. After comparing four kinds of stress controlling conditions, the relation to stress with depth of angular distortion, grade of curvature of angular distortion and half of region of angular distortion has been inferred. Graph of deformation allowable value of coke tower for different condition by angular distortion and half of region of angular distortion has been plotted. The five steps for its engineering use have been explained. The lighter the grade of curvature is, the larger of bulge allowance, may be, and the bigger of depth of angular distortion may pose too. For the coke tower with a popular structure of Dg 5 400 mm×28 mm, the result by graph is nearly more than the result of two formulas formed by other research, the error is less than 7.0%. But, the graph can be easily applied to different size of angular distortion.