基于ObjectARX的弧面分度凸轮机构参数化设计系统的研究

弧面分度凸轮机构是一种高速、高精度的空间分度机构,由于其工作廓面比较复杂,给设计带来了很大的难度.基于ObjectARX技术通过对AutoCAD软件的二次开发,开发了弧面分度凸轮机构参数化设计系统,实现了弧面分度凸轮机构的参数化设计、造型、压力角和诱导主曲率的分析等功能,为弧面分度凸轮机构的设计提供了软件平台.     

旋转凹模冷镦机弧面凸轮分度机构设计与仿真

建立了旋转凹模冷镦机弧面凸轮分度机构的数学模型,并结合实际应用情况设计了弧面凸轮分度机构参数,选取了弧面凸轮轮廓曲面运动规律。最后通过具体实例,使用Pro/E、Matlab对弧面凸轮工作轮廓面进行参数化建模,使用ADAMS建立弧面凸轮分度机构动力学模型,并对其运动性能进行了模拟仿真。研究表明,弧面凸轮分度机构作为旋转凹模冷镦机传动件在高速工况下运动平稳、停歇期定位精度达到36″。     

基于Pro/E的球形滚子弧面凸轮分度机构的建模与仿真

球形滚子弧面凸轮分度机构是用钢球代替圆柱,实现高精度、零背隙、低噪声的分度装置.文中先推导了任意回转面滚子从动件弧面凸轮的廓面方程,进一步得到了球形滚子弧面凸轮廓面方程;基于Pro/E软件构建了弧面凸轮和球形滚子的三维模型,并进行了运动仿真.运动分析结果表明了文中所提方法的有效性和通用性,为球形滚子弧面凸轮分度机构的运动学和动力学研究奠定了基础.     

弧面分度凸轮机构基础理论研究

随着我国经济快速的发展,机械工业向着高效、高速、精度高、噪声低和自动化方向发展,分度凸轮机构作为自动机械的关键部件其重要性日益凸显并得到了迅速的发展。本文介绍了弧面分度凸轮机构的结构形式,给出了常见的几种运动规律,给出其主要的运动参数与几何尺寸,指出弧面分度凸轮的工作廓面方程推导条件,介绍了弧面分度凸轮和滚子的材料及热处理,对研究弧面分度凸轮机构的结构、运动特性及规律提供了理论依据。     

基于齐次坐标变换的弧面分度凸轮建模与运动仿真研究

针对弧面分度凸轮机构,通过共轭曲面原理、微分几何学进行理论分析,提出了基于齐次坐标变换的通用弧面分度凸轮轮廓曲面方程建立方法;然后基于VB开发了弧面分度凸轮轮廓曲面数据采集系统;基于Pro/E建立了凸轮机构的三维模型及运动仿真模型。机构设计和运动仿真验证实例表明,设计机构满足预期分度要求。     

弧面分度凸轮机构参数化设计与仿真

以弧面分度凸轮机构为研究对象,基于VC 面向对象的方法及Pro/E二次开发技术,建立弧面分度凸轮参数化设计系统,该系统给出了界面友好的参数输入对话框,能够完成机构参数的自动综合和凸轮轮廓的自动生成,具有直观性,易于操作和调整,并在Pro/E环境下进行装配、仿真与干涉检测,验证了设计的合理性,为该机构的广泛应用提供了新方法和手段.     

偏心轴套在弧面分度凸轮机构中的应用

介绍了一种调整弧面分度凸轮机构中心距的方法.利用偏心轴套的偏心特性,实现了弧面分度凸轮机构中凸轮位置的移动,可以对弧面分度凸轮机构的中心距进行调整,在装配中使弧面凸轮与分度盘获得优良的配合,或对凸轮与滚子的磨损进行补偿,从而使弧面分度凸轮机构获得良好的动力特性和运动特性,实现了机构的连续、平稳、高速运转.     

弧面分度凸轮的Pro/E实体造型与VC++运动仿真

弧面分度凸轮的工作廓面复杂,设计繁琐,很难用常规的制图方法绘制.为了将复杂的凸轮机构可视化,实时地模拟其真实的运动状态,利用空间啮合原理建立了弧面分度凸轮的轮廓曲面方程.并采用模块化设计思想,基于Pro/E软件及VisualC 语言进行二次开发,实现了具有真实感的弧面分度凸轮的三维实体造型和运动仿真,为弧面分度凸轮机构的运动性能研究和企业的产品优化设计提供了软件平台.     

弧面分度凸轮机构的设计装配及运动仿真

弧面分度凸轮机构是空间凸轮机构的一种特殊结构形式,其凸轮曲面是通过与其啮合传动的分度盘上柱面滚子,按给定的运动规律互相包络而形成的空间不可展曲面。为了验证逆向设计出来的弧面分度凸轮的合理性和在应用中的可行性,对在给定条件下和弧面分度凸轮相配合的从动盘及滚子的设计参数,经过计算后通过Pro/E建模软件进行了简单的三维实体建模,并在Pro/E中进行装配,通过干涉分析来验证其合理性,进而又通过专业系统动力学分析软件ADMAS对完成的弧面凸轮机构进行运动仿真,经过分析该机构模型的运动情况,进一步来验证逆向设计出的弧面分度凸轮的合理性和可行性。     

基于Pro/E的弧面分度凸轮机构参数化设计与仿真

弧面分度凸轮机构是一种广泛应用于现代自动机和自动生产线上的高速、高精度的空间分度机构。但其凸轮的工作廓面复杂，设计繁琐，尤其是优化设计和高精度制造困难，因而影响了该机构的工作质量．也妨碍了其在国内的发展。从参数化和可视化的虚拟设计技术出发，基于Pro／ENGINEER大型CAD软件，应用VC 和和Pro/TOOLKIT对其进行了二次开发，建立了弧面分度凸轮机构的参数化设计、造型和运动仿真，以及包含凸轮压力角、诱导主曲率和误差分析等内容的设计系统，为弧面分度凸轮机构的运动性能研究和企业的产品优化设计提供了软件平台。     

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.     

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....     

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。     

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.