基于模糊优化理论的装配线平衡多目标优化

在生产制造系统中,装配线的平衡需要针对多个目标。基于模糊优化理论,对多目标装配线平衡问题建立模糊多目标非线性规划模型,系统考虑各目标之间的联系,求得问题的整体最优解。采用隶属函数处理各目标函数,能够求解出不同性质、相互矛盾的多个目标的满意程度及系统整体的满意程度。用隶属函数处理约束,使约束能够更方便、有效的反映实际生产环境,并提升目标的优化空间。通过示例分析证明,该模型能够有效的解决多目标装配线平衡问题。     

发动机环形混流装配线多目标排序方法

为了获得托盘数量固定的发动机环形混流装配线产品投产排序方案,提出一种多目标优化算法和离散事件仿真相结合的多目标排序方法.在该方法中,以最小化零部件消耗速率波动和最大化生产率为优化目标,建立解析-仿真混合模型;设计了一种内嵌离散事件仿真的自适应多目标遗传算法求解问题;采用组件对象模型(COM)技术,将离散事件仿真求解的生...     

基于混合粒子群算法求解多目标混流装配线排序

针对生产调度中的多目标混流装配线排序问题,建立以最小化超载时间、产品变化率与总切换时间为优化目标的数学模型,并提出一种改进的多目标粒子群算法求解。该算法采用基于工件的编码方式,并提出新的解码方法;应用Pareto排序和小生境数评价个体,在此基础上形成了一种新的适应度函数。在个体最优解的更新中,为避免最优解丢失,对非支配粒子与支配粒子采用差异化方法更新。此外,运用两种策略解决粒子群算法过早收敛的问题:在个体最优解的更新中引入模拟退火思想,并将全局最优解的选择扩大到整个种群。通过数值算例研究了算法的收敛性、分布性和执行效率,结果表明了所提算法的优越性。     

基于Vague集的机械设计方案多目标模糊决策方法

在现有多目标模糊决策方法的基础上，提出了一种改进的基于Vague集的多目标模糊决策算法及其在机械设计方案决策中的应用方法。通过建立一个函数来评价每个方案满足决策者需要的适合度，其中方案的特征由Vague集表示，改进的评价函数算法包含了肯定隶属度、否定隶属度和不确定度（踌躇度）等因素，并且算法中所定义的函数含义更明确。实例阐明了本文基于Vague集的多目标模糊决策方法的合理性，机械设计方案多目标模糊决策取得了较为满意的结果。     

混流轿车总装配线的动态规划与仿真优化研究

为设计合理的轿车总装线和提高生产效率,分析了其总装工艺流程及特点.建立装配线负荷平衡的数学模型及在3种不同阶段时的目标函数,确定了设计参数的上下界限并分析了各种启发式求解算法.采用最小生产循环来研究混流装配线的产品投产排序问题,建立了基于闭环工位时间移动窗口的最小化装配线空闲与超载时间和准时生产环境下零部件消耗速率均匀化的目标函数,并分析了3种优化算法.在数字化工厂软件eM-Power的平台上建立了轿车总装车间的底盘工段与分装工段部分工位的仿真对象模型及控制逻辑.最后,进行了生产评估并验证了所建模型的有效性.     

基于多目标猫群算法的混流装配线排序问题

针对现实混流装配线上各工作站内设备闲置/超载的成本不同的问题,在传统的最小化闲置/辅助工作总成本目标的基础上,考虑不同工作站内设备闲置/超载成本的差异,建立了以改进的最小化工作站闲置/超载总成本、产品变化率和产品切换总时间为目标的多目标优化模型,并设计一种改进多目标猫群优化算法进行求解。提出一种基于线性混合比率的猫行为模式选择方法,以提高算法前期的全局搜索能力和后期的局部寻优能力;提出能生成分布广泛的候选个体、基于多样化搜寻算子的改进搜寻模式,拓展算法的搜索空间,提高算法的全局搜索能力。运用基准实例对所提算法与第二代非支配排序遗传算法、多目标粒子群算法、第二代强度Pareto进化算法进行比较,结果表明所提算法在解的收敛性、分布性和Pareto解的搜索能力上均具有优势。将该算法用于求解某实例企业的混流装配线排序问题,为车间调度人员的决策提供了多样化的选择,且优于车间已有方法的求解结果。     

基于装配关系复杂性测度的多目标混流装配线平衡优化

在混流装配线中,各工作站装配关系复杂性会影响作业效率和工人负荷.基于信息熵对装配关系复杂性进行度量,以最小化生产节拍、装配线平滑指数和装配关系复杂性平滑指数为优化目标,建立多目标混流装配线平衡优化模型,运用第二代非支配排序遗传算法(NSGA 2)设计求解,并结合某企业混流装配线实例验证方法的有效性.研究结果表明该优化方...     

非同步混装线负荷平衡与投产排序集成优化方法

为了提高非同步混流装配线的生产效率,提出了一种负荷平衡和投产排序的集成优化方法.首先通过综合优先图,将多品种装配线平衡问题转变成单品种平衡问题;通过设计组合优先启发式方法,以最小化生产节拍为目标,生成平衡方案;在平衡方案基础上,按照生产需求,采用考虑有限缓冲区容量的NEH(Nawaz-Enscore-Ham)算法,获得...     

混流装配线排序问题的研究现状与展望

目标函数的选取与排序问题的求解方法是解决混流装配线排序问题的两个关键问题,通过对混流装配线排序问题的国内外研究现状分析,并根据不同的优化目标,归纳出了不同类型目标函数并给出相应的数学模型;同时对排序问题的各种求解方法进行了分析和评价．重点介绍了人工智能方法。在此基础上,对混流装配线的发展进行了展望。     

仿真环境下混流装配线平衡和排序的优化研究

针对某企业风电制动器混流装配过程中工位负载不均衡而导致排队时间过长、装配效率低、无法满足顾客订单需求的问题，提出在并行考虑混流装配线平衡和排序相互影响的基础上，建立最小化最大完工时间、最小化工位负荷指数的多目标优化模型，提出一种基于Pareto改进的果蝇优化算法，采用混合并联编码由工位数量、工位类型及载料框上料顺序三部分组成，并引入多种群策略、自适应步长、精英保留策略，确保优良个体不被破坏。基于实例分析及数据基础，通过Python语言开发环境进行开发算法程序，将得到新的平衡和排序方案与标准遗传算法求得的平衡和排序方案，在离散系统仿真软件Plant Simulation平台上对以上两种算法得到的最优平衡和排序方案进行仿真，验证该算法的有效性。     

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...     

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.     

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。     

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...     

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。     

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。     

Fifth International Summer School on Screw-Theory Based Methods in Robotics

正3-11 September,2014University of Bologna,Bologna,Italy www.summerscrews.org summerscrews2014.ing.unibo.it SUMMER 20SCREWS 14In 2014,our screw-theory school comes to the world's oldest university.In early September,Summer Screws'14 will gather six experts in the application of screw theory in robotics and up to 40 participants at the University of Bologna,Bologna,Italy.The school will teach attendees how to apply existing methods and empower them to develop new ones in their own research.The basic theoretical notions will be introduced in a rigorous manner,emphasizing examples,applications,and exercises.Scholarships are available.     

交通荷载作用下桥梁结构参数识别方法

应用动力节点加载法,将作用在桥梁上的交通荷载转化为等效节点荷载,再用两步构造法识别结构物理参数.第1步,用Newmark-β方法变换结构运动方程,并用结构的加速度响应求得变换空间内的位移、速度和加速度响应;第2步,基于最小二乘原理,构造出变换空间内求解结构参数的递推式,进行结构物理参数识别.数值模拟结果表明,在交通荷载作用下,该方法能够快速、准确地进行桥梁结构参数识别.     

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.     

INDUSTRIAL ENGINEERING AND VISUALISATION-A PRODUCT DEVELOPMENT PERSPECTIVE

Taking the actual project of teaching and researching process for example, the relationship between the industrial engineering and product development is discussed. And use the novel visualization technology to support the industrial engineering and product development. How to use the new computer modeling and simulating technologies to support the product development and industrial engineering, is introduced especially. The support includes both domestic products and industrial systems. The visualization and computer technologies take a very important role in some system or multi-direction modeling, those technologies mentioned above can help the industrial engineers study the effect of design on the whole life circle, including the producing steps. So the engineers can avoid making the wrong decision which may cause bad effects on the whole industrial engineering.