拆卸序列规划中子装配体的识别与生成

子装配体识别是解决大规模拆卸序列规划"组合爆炸"问题的有效方法之一.为了准确有效地识别与生成子装配体,在装配体零部件间接触关系、联接关系和向位妨碍关系及其相应图模型、矩阵的基础上,提出了一种基于图模型和判断矩阵的拆卸序列规划子装配体的识别算法.该算法利用图模型对子装配体集合做加法,利用判断矩阵对子装配体集合做减法,首先依据子装配体识别准则对图模型检索生成潜在子装配体集合,然后依据矩阵判断公式从集合中排除不符合连续性原则、稳定性原则和可行性原则的子装配体,并筛选理想个数的符合重量标准、同质标准和价值标准的最终子装配体集合.以减速器实例验证方法的可行性和有效性.     

基于自动拆卸过程的装配序列生成方法研究

装配序列生成是装配工艺规划的基本任务,设计了一个基于自动拆卸过程的装配序列生成算法。首先,进行自动拆卸仿真,通过过程中的干涉检查生成可行的装配序列集。然后,定义了三类装配序列优先约束规则,对可行序列集进行过滤选择,得到可用于最终评价的少量装配序列。该算法在SolidWorks平台上得到了实现,给出了实例验证。     

Design for manufacturing and assembly/disassembly: joint design of products and production systems

Design for Manufacturing, Assembly, and Disassembly is important in today’s production systems because if this aspect is not considered, it could lead to inefficient operations and excessive material usage, both of which have a significant impact on manufacturing cost and time. Attention to this topic is important in achieving the target standards of Industry 4.0 which is inclusive of material utilisation, manufacturing operations, machine utilisation, features selection of the products, and development of suitable interfaces with information communication technologies (ICT) and other evolving technologies. Design for manufacturing (DFM) and Design for Assembly (DFA) have been around since the 1980’s for rectifying and overcoming the difficulties and waste related to the manufacturing as well as assembly at the design stage. Furthermore, this domain includes a decision support system and knowledge base with manufacturing and design guidelines following the adoption of ICT. With this in mind, ‘Design for manufacturing and assembly/disassembly: Joint design of products and production systems’, a special issue has been conceived and its contents are elaborated in detail. In this paper, a background of the topics pertaining to DFM, DFA and related topics seen in today’s manufacturing systems are discussed. The accepted papers of this issue are categorised in multiple sections and their significant features are outlined.     

A fast branch,bound and remember algorithm for disassembly line balancing problem

In recent years, the interests of disassembly line have increased owing to economic reasons and the increase of environmental awareness. Effective line can provide many advantages in terms of economic aspect and it facilitates competition the companies with others. This study contributes to the relevant literature by a branch, bound and remember algorithm for disassembly line balancing problem with AND/OR precedence. The proposed exact solution method employs the memory-based dominance rule to eliminate the reduplicated sub-problems by storing all the searched sub-problems and to utilise cyclic best-first search strategy to obtain high-quality complete solutions fast. In this paper, minimising the number of stations is taken as the performance measure. The proposed methodology is tested on a set of 260 instances and compared with the mathematical model using CPLEX solver and five well-known metaheuristics. Computational results show that the proposed method is capable of obtaining the optimal solutions for all the tested instances with less than 0.1?seconds on average. Additionally, comparative study demonstrates that the proposed method is the state-of-the-art algorithm and outperforms the CPLEX solver and metaheuristics in terms of both solution quality and search speed aspects.     

Joint decision-making on automated disassembly system scheme selection and recovery route assignment using multi-objective meta-heuristic algorithm

Green treatment on Waste Electrical and Electronic Equipmenthas increasingly attracted attention due to its significant environmental benefits and potential recovery earnings. Automated disassembly has been regarded as a powerful solution to enable more efficient recovery operations. Although numerous studies have contributed to the issues of disassembly, there are few researches that focus on decision model for selecting disassembly system scheme and recovery route in automated disassembly. In this paper, we propose a two-phase joint decision-making model to address this problem with the goal of balancing disassembly profit with environmental impact. First, we establish a multi-objective optimisation model to obtain the Pareto optimal recovery routes for each automated disassembly system scheme. Both recovery profit and energy consumption are evaluated for multi-station disassembly system. We design a multi-objective hybrid particle swarm optimisation algorithm based on symbiotic evolutionary mechanism to solve the proposed model. Then, we compare the Pareto optimal solutions of all the system schemes using a fuzzy set method and identify the best scheme. Finally, we conduct real case studies on the automated disassembly of different waste electric metres. The results demonstrate the superiority of automated disassembly and validate the effectiveness of our proposed model and algorithm.     

基于概率图模型的单信标定位算法研究

随着人类对海洋认识的逐步深入,水下目标的位置信息成为了一种不可或缺的水下信息源,传统的水下定位方法已经不能满足不同场景的应用需求。无论是在测量信息多元化时的多元信息融合定位,还是测量信息不足时的时域信息联合定位时均存在局限性。为此文章提出了基于概率图模型的单信标定位算法,在信标稀疏或者信标通信信息缺失的情况下,通过联合目标时域上其他位置时刻的所有量测信息,从而实现目标定位。此外文章还分析了模型分辨率和测距误差对定位结果的影响,并通过湖试验证概率图方法的有效性,证明其能够在传统定位方法无法使用的单信标的定位跟踪过程中,估计出每一时刻目标的位置,描述目标的运动轨迹。平均定位精度达到1.203 5 m。     

与或功能树的无损简化方法

当前概念设计中较大规模功能树存在解空间庞大、冲突定位困难的问题,对此提出基于与或功能树的无损简化方法。证明了无损收缩简化、无损删除简化、无损提取简化的相关定理,并籍此给出与或功能树的无损简化算法。最后通过实例,证明该算法可在保持逻辑等价和创新能力不损失的前提下有效降低问题的复杂度,从而提高了概念设计的效率。     

Topology optimization of trusses using genetic algorithm,force method and graph theory

In this article size/topology optimization of trusses is performed using a genetic algorithm (GA), the force method and some concepts of graph theory. One of the main difficulties with optimization with a GA is that the parameters involved are not completely known and the number of operations needed is often quite high. Application of some concepts of the force method, together with theory of graphs, make the generation of a suitable initial population well‐matched with critical paths for the transformation of internal forces feasible. In the process of optimization generated topologically unstable trusses are identified without any matrix manipulation and highly penalized. Identifying a suitable range for the cross‐section of each member for the ground structure in the list of profiles, the length of the substrings representing the cross‐sectional design variables are reduced. Using a contraction algorithm, the length of the strings is further reduced and a GA is performed in a smaller domain of design space. The above process is accompanied by efficient methods for selection, and by using a suitable penalty function in order to reduce the number of numerical operations and to increase the speed of the optimization toward a global optimum. The efficiency of the present method is illustrated using some examples, and compared to those of previous studies. Copyright © 2003 John Wiley & Sons, Ltd.     

基于权重比的车架多工况拓扑优化方法研究

在赛车实际行驶过程中车架会受到各种工况的考验,因此在进行车架结构拓扑优化设计时必须同时考虑多个工况下车架的拓扑优化结果.然而,在进行多工况下拓扑结构设计时往往会遇到如何分配各个工况权重比的问题,各工况权重比的分配直接影响车架最终的拓扑结构.针对此问题进行研究,通过构造代理模型并利用遗传算法寻找最佳权重比.首先,采用折衷规划法建立同时考虑多个工况下车架刚度的拓扑优化综合目标函数模型;接着,采用最优拉丁超立方试验设计方法采样,构造径向基函数代理模型,并在代理模型的基础上利用NSGA-II进行求解,得到各个工况最佳权重比;最后,将获得的各个工况最佳权重比代入综合目标模型中进行拓扑计算,获得同时考虑各工况下车架刚度的拓扑结构.将该方法与获得权重比常用的层次分析法(AHP)和正交试验法(OED)进行比较,该方法较其他两种方法得到的综合目标值是最优的,车架所有工况的加权柔度是最低的.结果表明,所提出的方法很好地解决了多工况下拓扑优化权重比分配的问题,并且较其他方法具有明显的优越性.     

煤岩灾害动力现象危险性预测中的定向定位研究

为了更好地应用非接触电磁辐射方法预测预报煤岩灾害动力现象的危险性，借助于力电耦合方程计算出在天线的各个朝向电磁辐射信号的变化规律及对某一个固定监测点结果的比较，就可以确定出某一个监测点电磁辐射信号的最佳监测方向以及应力变化最大（即危险性最大）的方向；在巷道掘进过程中进行巷道迎头电磁辐射动态监测时，天线测定的位置应该放置在巷道高度方向的中部，并对着煤层层理方向，通过不断改变天线朝向来监测巷道迎头和两帮煤岩层的突出危险性；可以通过应力场数值模拟得出的应力集中区来确定有效预测距离的范围。现场电磁辐射信号测定结果     

软段结构对聚氨酯-聚丙烯酸酯复合乳液乳胶粒形态结构的影响

为了探讨聚氨酯水分散液(WPU)的软段结构对聚氨酯-聚丙烯酸酯复合乳液(PUA)乳胶粒子形貌结构的影响,首先分别合成了不同软段结构的WPU,然后以其为种子乳液并滴加溶有引发剂的丙烯酸酯混合单体形成预乳液,升温聚合后得到PUA。通过对乳胶粒径测试和形貌观察发现,软段分子量较小时,形成的PUA乳胶粒没有明显的核/壳结构,软段分子量较大时,形成过渡层型、梯度型和草莓型结构的核/壳结构PUA乳胶粒,采用两种分子量的软段共混得到的PUA乳胶粒具有复杂的核/壳结构。     

风氢互补发电系统构建初探

为了解决风力发电输出功率的不平稳性和电压的波动性,以解决并网的瓶颈问题,提出风氢互补发电系统,将风力发电输出"波谷"对应的可控出力作为风电场能保证恒定输出的功率,"波峰"至"波谷"之间对应的不可控的出力,采用"波峰"制氢进行"削峰"、"波谷"氢气发电进行"填谷"的方式进行平衡。并以如东风电场为例进行了实例分析与计算,结果证明采用该风氢互补系统基本能保证发电输出平衡,是解决风电并网有效可行的途径。