基于映射的产品装配建模技术研究

根据自顶向下的设计要求,提出基于映射技术的功能模型向装配模型的转换方法.通过信息实例化及规则表达,保证了映射技术的可行性.通过建立不同的实例库和Mapping表,较好实现了模型信息的转换.通过功能单元映射为装配单元,功能间约束映射为装配连接特征以及装配关系,实现了设计约束的自顶向下传递和功能设计与结构设计的集成.利用二叉树对模型交互进行装配序列化处理,保证了装配模型结构的完整性与可装配性.通过开发原型系统验证了该方法的可行性.     

基于装配的冲模三维CAD系统

在分析冲模结构设计特点的基础上,介绍了在UG装配环境下所开发的冲模三维CAD系统的设计流程和实现方法,并对系统的主要功能模块和关键技术做了概括性介绍.     

基于三维轻模型的装配MES系统关键技术

针对现阶段产品设计已经实现三维数字化,但在航空等典型离散行业的制造现场仍以二维工程图为产品制造依据的现实,提出了基于三维轻模型的装配MES系统,将产品设计数据向制造过程延伸,并结合MBD( ModelBased Definition,基于模型的定义)技术实现基于三维轻模型的装配工艺定义,以三维轻模型为车间现场装配生产的...     

基于装配相似性与灰色模型的汽车装配工时预测

汽车企业为适应市场需求的不断变化,加快了推出新车型产品的步伐。针对目前汽车总装混流工时预测速度缓慢的问题,提出基于装配相似性与灰色理论GM（0,N）模型的装配工时预测方法。将装配工时按特性分为取料时间、定位时间和连接时间,提取影响各部分工时的关键因素,通过计算样本与基准零件的装配相似系数,结合装配工时在MATLAB中构建拟合曲线,最后在函数关系式和GM（0,N）模型中分别预测定位时间和连接时间。通过与MTM法进行比较,证实该方法具有准确性和高效性。     

装配工艺自动化设计技术的研究

装配工艺自动化设计(计算机辅助装配工艺设计——CAAPP)的研究在国内外处于起步阶段,它对CIMS环境下开展并行工程的研究及促进工厂自动化具有重要童义。本文对此领域的技术进行了探讨性研究,文中提出了计算机辅助装配工艺设计应采取的研究方法;介绍了系统的基本结构;并对装配顺序的决策思想及方法作了较详细的分析。     

基于装配顺序的飞机装配容差信息建模

论文提出了基于装配顺序的装配容差信息建模方法,以装配仿真路径规划的装配顺序为基础,提取装配体中各零件的特征约束关系及相关的关键特征,进而获取组成环容差信息,建立装配容差信息模型。该模型考虑了装配顺序对装配误差累积过程的影响,减少了人工容差信息建模繁琐的交互操作,提高了装配容差信息的建模质量。基于DELMIA平台开发了飞机装配仿真系统。该系统已在工程上成功应用,提高了飞机装配仿真的效率,减少了飞机实际装配生产中的出错率。     

基于产品配合图的装配顺序自动规划

装配顺序规划( ASP) 是基于装配建模的装配工艺顺序的自动规划生成, 是DFA( 面向装配的设计) 的关键技术之一。本文采用配合条件法进行装配顺序求解, 装配体采用其部件与部件间的配合关系来描述, 从部件间的配合关系可得到其装配体配合图。本文还在原算法的基础上添加了一些约束来降低算法的计算量, 使得算法更为简洁。该法在AutoCAD®设计平台上实现, 并采用装配体实例加以检验。     

支持操作的装配仿真技术研究

 装配仿真作为一种可视化工具 ,能适时检测和改进产品可装配性 ,是DFA研究的基础关键技术。通过建立装配操作模型 ,实现对装配操作、装配工具、装配夹具等信息的集成 ,并将产品装配环境和装配过程有机地结合在一起 ,实现高层次装配仿真。所提出的算法均已应有于DMAS系统中 ,取得了良好的实际效果。     

产品可装配性设计方法和使能技术研究

产品可装配性设计（ＤＦＡ）理论研究,对实施并行工程具有重要的意义,上前得到广泛的重视。本文从实现ＤＦＡ目标出发,提出了ＤＦＡ的设计系统模型,论述了ＤＦＡ设计方法的相关使能技术,如并行装配设计、装配结构和装配性能分析、装配约束分析、装配序列规划、装配公差分析等。     

基于网络的虚拟装配可视化技术研究

分析了在计算机上实现虚拟装配的流程及如何用VRML创建三维可视化的虚拟场景，提出一种基于VRML和Java的虚拟现实构建方法，用以增强VRML虚拟场景与外界的交互性，并以球阀为例给出了在网络上创建虚拟装配动画演示的具体方案．该方法不仅可用于演示网络环境下的可视化装配，也适合于其它领域基于Web的科学可视化。     

A cost estimation model to support automation decision in assembly systems design

Cost analysis is crucial in the design of assembly systems and the decision on their level of automation (LoA). This paper presents a cost estimation model of assembly system that is used to decide their LoA during the early phase of projects. Based on an extensive literature review, a complete cost model integrating multiple cost drivers is proposed. This model is then exploited to create the objective function of an integer linear programme model utilised to solve the LoA decision problem. The work provides a way to perform cost estimation of assembly systems alternatives and to decide the most appropriate LoA in assembly. The cost estimation model is built with a parametric approach allowing the definition of various optimisation objectives. The proposed integer programme, complement this approach by proposing the suitable constraints set, that describes the LoA decision problem.     

可装卸式加油设备的管路系统装配设计研究

由于在不同装配空间的管路系统装配结构存在相似性和差异性,可装卸式加油设备的管路系统装配设计十分复杂．针对该问题,提出了基于谱系聚类法的管路系统装配空间聚类方法,使聚类后的每类装配空间能够通用多套已装配好的管路系统．通过定义类的典型装配空间及装配半径,使新设计的加油设备按其管路系统装配空间尺寸,迅速地找到符合要求的已装配好的管路系统．最后,以对一些典型的装配空间进行聚类及如何应用聚类结果为例,验证了该方法的有效性和合理性．     

基于均匀设计方法研究不锈钢焊条的脱渣性

为了定量地分析药皮辅料对焊条工艺性能的影响,利用中国数学会均匀设计分会推荐的UST4.0软件安排配方试验并处理数据,研究了不锈钢焊条的脱渣性.试验中,将10种辅料怍为自变量,焊缝的脱渣性作为目标函数.通过数理统计给出了每种药皮辅料影响焊缝脱渣性的趋势图,并建立了10种药皮辅料及其交互作用对应干脱渣性的数学模型.研究表明:金红石、钛白粉、电解锰、钛铁和白泥对焊缝脱渣性的影响都为正相关;冰晶石和萤石对焊缝脱渣性的影响为负相关;绝大多数药皮辅料对焊缝脱渣性的影响呈交互作用的形式.     

A heuristic based on Vogel's approximation method for sequencing mixed-model assembly lines

Sequencing mixed-model assembly lines is a well researched topic in the literature. However, many methods that have been developed to solve this problem fail to cope with either the large size or the specific characteristics of real-life problems. In this paper, a heuristic is proposed that is derived from Vogel's approximation method for transportation planning. The heuristic is able to handle large and supposedly difficult problem instances. Sophisticated test scenarios considering real-life aspects were generated to evaluate the performance of the heuristic for realistic problem instances. It is shown that the proposed heuristic significantly outperforms priority rule-based methods and requires only reasonable computational effort.     

基于VRML模型的协同装配工艺规划仿真方法

在研究了虚拟现实建模语言(VRML)模型特点以及协同装配工艺规划过程的基础上,将以VRML三维模型为设计信息载体的协同装配工艺规划仿真分为无约束的规划仿真和基于约束的规划仿真,并提出了相应的实现方法.所提方法使网络化的同步协同装配规划操作成为可能,通过实时交流,使产品装配工艺规划能够在集合多方设计经验的基础上方便快捷地实现.应用实例的应用结果表明,所提方法可快速发现设计缺陷并显著地缩短产品工艺规划周期.     

Response surface method based on uniform design and weighted least squares for non-probabilistic reliability analysis

The non-probabilistic reliability theory is a promising methodology for implementing structural reliability analysis in case of scarce statistical data. One of the main obstacles to implement non-probabilistic reliability analysis is the implication of the limit state function (LSF) for complex structures. This paper aims to establish a surrogate model of the LSF with higher simulation precision, and whereby proposes a response surface method based on the combination of uniform design (UD) and weighted least squares (WLS). At first, the UD method is selected as the sampling method of interval variables to realize the uniform space-filling of the initial samples, and the sample set is updated by gradually adding the approximate optimal points to increase the sampling density of critical domain. Then, the WLS method is applied to improve the precision of the response surface by adjusting the importance of samples to the function fitting. Finally, a method of constructing sample weights is developed. Two examples are applied to validate the feasibility and efficiency of the proposed method. Results show that the proposed method is effective for non-probabilistic reliability analysis of complex structures owning to high computational precision and low computational cost in both numerical and case study.     

Ergonomics in assembly line balancing based on energy expenditure: a multi-objective model

In many assembly systems, ergonomics can have great impact on productivity and human safety. Traditional assembly systems optimisation approaches consider only time and cost variables, while few studies include also ergonomics aspects. In this study, a new multi-objective model for solving assembly line balancing problem is developed and discussed in order to include also the ergonomics aspect. First, based on main features of assembly workstations, the energy expenditure concept is used in order to estimate the ergonomics level, thanks to a new technique, called Predetermined Motion Energy System, which helps rapidly estimate the energy expenditure values. Then, a multi-objective approach, based on four different objective functions, is introduced in order to define the efficient frontiers of optimal solutions. To complete the study, a simple numerical example for a real case is presented to analyse the behaviour of Pareto frontiers varying several parameters linked to the energy and time value.     

Mixed model assembly system with multiple secondary feeder lines: layout design and balancing procedure for ATO environment

The constant research for efficiency and flexibility has forced assembly systems to change from simple/single assembly lines to mixed model assembly lines, while the necessity to reduce inventory has led the transition from single to multi-line systems, where some components are assembled in secondary lines, called feeder lines, connected to the main one by a ‘pull philosophy’. A possible approach to configure such an assembly system is to balance the main line first and use the retrieved cycle time to balance each feeder line separately, which is a questionable solution, especially if operators can perform tasks on both the feeder and the main line. Moreover for its complexity the mixed model balancing problem is usually solved transforming it into a single model by creating a single ‘virtual average model’, representative of the whole production mix. The use of a virtual average model assumes that the processing times of some models are higher or lower than the cycle time, which creates overload/idle time at the stations. This approach, especially in complex multi line production systems, largely reduces the assembly line productivity and increases the buffers dimensions. This paper faces the mixed model assembly line balancing problem in the presence of multiple feeder lines, introducing an innovative integrated main-feeder lines balancing procedure in case of unpaced assembly systems. The proposed approach is compared with the classical one and validated through simulation and industrial applications.     

An integrated model for assembly line re-balancing problem

In this paper, an integrated approach for assembly line rebalancing problem (IALRP) is proposed to quickly react and find an optimal rebalancing of the line when disruptive event occurs because of product demand changes. This model is motivated by real-life application of an automotive cable manufacturer which provides more realistic constraints. To solve the problem, we propose a genetic algorithm (GA) hybridised with a heuristic priority rule-based procedure. This hybridisation is used to add more rich seeds to the initial population and consequently to improve the convergence capability and performance of the GA. After the disturbance, we aim to find a rebalance with the proposed approach to maximise the line efficiency and distributing the idle time across the workstations as equally as possible. To evaluate the efficiency of the proposed algorithm, set of samples collected from the literature are used. The real case study and the experiment results show the proposed approach is very effective and competitive.