基于RFID的混流装配汽车生产线物料动态配送研究

针对混流装配的汽车自动化生产线提出了基于RFID的车辆追踪和基于条码的无线物料库存管理实现方法.在此基础上,设计了装配生产线的物料动态配送调度业务流程,给出了物料动态配送的规划依据,并进行了实例计算.     

不确定环境下混流装配线动态准时制物料配送系统

针对不确定环境下混流装配线物料配送准确性和及时性的问题,构建了一种基于射频识别技术的动态准时制物料配送控制系统。分析了混流装配线的物料配送特点及物料分类,阐述了生产计划变动、生产节拍波动、线边库存及物料需求量和时间等物料配送中的不确定因素。综合考虑各类不确定因素,构建了基于射频识别的动态准时制物料配送体系架构,建立了可视化装配过程监控系统,研究了物料配送方案运算模型,设计了物料配送控制系统的硬件架构和软件体系结构。以某公司的1.5TGDI发动机工厂的混流装配线为例,应用J2EE构架开发了基于射频识别的动态准时制物料配送系统,实现了物料配送管理和控制的一体化和可视化,验证了系统的可行性和有效性。     

Kitting物料配送在混流装配线的应用研究

对混流装配过程中由物料配送不及时引起的生产计划不连续的问题进行了研究,在分析了混流装配生产模式后,构造出了在该生产模式下的混流装配线线旁物料kitting(齐套性)算法,再根据物料kitting(齐套性)算法预求出混流装配线各个工艺点物料消耗,在此基础上求出各个工艺点物料需求,从而带动物料配送;最后通过实例,验证上述方法的可行性和实用性.     

基于混流生产模式的装配车间物料配送路径规划方法

合理规划物料配送路径能够提升车间生产效率,降低车间物流成本和生产成本。针对混流装配车间配送不及时、费用高等问题,提出基于混流生产模式的物料配送路径规划方法。以工位为物料配送对象,对混流装配车间物料配送环境进行分析,找出混流装配线的物料消耗规律,明确物料配送数量,简化物料配送过程。在此基础上,结合生产实际的时间窗约束,以最小化物料配送总费用为目标建立了物料配送模型,采用改进蚁群算法对该模型进行求解,最后以某视频控制卡混流装配车间为实例,验证了该方法的可行性和有效性。     

SPS模式下物料消耗平准化的混流装配线车型排序

在混流生产过程中,针对零部件供应不能实现JIT的问题,提出在SPS物料配送模式下,提高零部件消耗平准化程度。在汽车混流装配线中最重要的目标是零部件消耗速率平准化,建立了混流装配线车辆排序模型。结合W公司实际案例,验证了车型排序在平准化物料消耗中的重要意义。     

混流装配线物料配送仿真与优化

混流装配线的准时制物料配送对Makespan有着显著影响.利用Plant Simulation仿真软件建立了一般MTO企业混流装配线的物料配送系统仿真模型,建立了配送系统参数对Makespan影响的数学模型.通过仿真试验设计的方法,优化配送系统中的搬运小车的数量及速度、装载量大小及线边暂存区最大最小库存量.     

混流轿车总装配线上物料配送的研究与实践

为满足混流轿车总装配线上物料及时准确的配送,分析了轿车总装工艺流程和生产特点,依据轿车零部件的形状将物料划分为3类。研究了准时生产环境下物料配送的物料拉动系统和看板运作流程,并建立了基于现场总线技术的物料ANDON系统。在分析总装线旁物料报警情况的基础上,提出了现场物料出现MIN／MAX时的处理方式,提出了物料断点的概念并建立了实施流程。根据某轿车总装配流水线的实际物料需求,设计了混流装配线分布式物料管理信息系统的功能模块,以及基于J2EE平台的软件架构,开发的信息系统已应用于某企业。     

复杂产品装配执行过程的渐增式物料齐套与周转状态管理技术

针对多品种、少批量的复杂产品在装配执行过程中对物料供应及时性、准确性、完备性的需求,提出面向装配执行过程的渐增式齐套协调与物料周转状态管理技术。以工序级的结构化装配物料齐套工艺数据为基础,通过物料内容、时间和配送协同的管理,建立了以装配执行过程为主线、以工艺流程节点为核心、以物料需求状态为管理对象的渐增式齐套状态协调机制;针对车间对有限装配物料资源合理分配的需求,建立了齐套优先级评价模型,并与生产计划时间节点相结合,实现了物料审批的优化;提出扁平化车间库存管理体系及二维码物料托盘配送技术,实现了周转的齐套物料资源托盘准备与车间物料供应的闭环控制。结合实际的工程实例运行分析,验证了技术的合理性与有效性。     

面向机械产品装配过程的物料配送方法研究

针对机械产品装配过程中的实时物料配送问题,在分析实时物料配送过程的优化目标、影响因素以及约束条件的基础上,重点研究了一种与制造执行系统结合的实时物料配送方法。通过生成物料配送计划、对物料进行跟踪管理以及实时反馈机制的运用,实现了装配车间物料的实时、小批量配送,并通过实例验证了上述方法的有效性和可行性。     

基于RFID的汽车总装物料配送过程的Petri网建模与仿真

分析准时化生产环境下汽车制造企业总装现场物料配送过程.将射频识别技术融入准时化生产管理模式,研究了基于射频识别技术且与装配流程协同运作的总装现场物料配送过程.用赋时着色Petri网对该过程建立模型并进行仿真分析,所获得的结果可为描述与分析基于射频识别技术的汽车总装现场物流配送过程提供一定的参考和依据.     

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...     

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.