供应商参与下的产品部件设计方案选择模型

研究了供应商参与下新产品部件设计方案的选择问题。通过引进综合表现度的概念来表征部件设计方案对成形产品顾客满意度的贡献。基于模糊综合评判、综合供应商的评价等级及备选方案的表现度,确定各设计方案的综合表现度。基于质量功能配置思想,建立了产品规划和部件规划质量屋。利用质量屋的信息和部件设计方案的综合表现度,建立了供应商参与下部件设计方案选择的组合优化模型。该模型考虑设计制造企业的成本约束,以产品部件组合方案的综合表现度最大为目标。以液晶显示器为实例,说明了模型的应用。     

Optimal selection of machining direction for three-axis milling of sculptured parts

In the field of free form surface machining, CAM software allows management of various modes of tool-path generation (zig-zag, spiral, z-level, parallel plan, iso-planar, etc.) leaning on the geometry of the surface to be machined. Various machining strategies can be used for the same shape. Nevertheless the choice of a machining strategy remains an expert field. Indeed there are no precise rules to facilitate the necessary parameter choice for tool-path computation from analysis of the numerical model of a part and the quality requirements. The objective of this paper is to provide a method to assist in the choice of the machining direction for parallel plane milling of sculptured parts. The influence of the tool-path on final quality according to the intrinsic geometrical characteristics of the latter (curves, orientation) was studied. Directional beams are introduced and defined from the local surface parameter. Finally, a methodology to optimize machining time while guaranteeing a high level of quality was developed and applied to examples.     

Knowledge-based selection and sequencing of hole-making operations for prismatic parts

This paper describes the rule structure used to select the appropriate sequence of operations to produce various types of holes in 2 1/2D prismatic components manufactured on machining centres. Operation selection is based on forward chained rules coded in Prolog. A different rule priority sequence is applicable depending on the rule fired last. This solves the conflict resolution problem and ensures reasonably fast execution. Rule conditions perform feature extraction, feature size checks, operation suitability checks, tool suitability checks and processing status checks. Actions perform the processing operations and update the model through feature processing tags. The knowledge base implemented for hole-making was not obtained from a practical industrial environment. Nevertheless it does produce sensible plans and it is relatively easy to modify.     

Integrated assembly and machining planning for electronic products using a genetic algorithm approach

To produce an electronic product, both assembly operations and machining operations are required in the process plan. In most cases, the assembly operations and machining operations need to be combined in a continued order with an integrated sequence. This is different from the traditional process planning approaches in which machining operations and assembly operations are separated as two independent tasks with no interactions. For an electronic product, the two types of operations and the associated costs may affect each other in an interactive way. Therefore, the sequence planning of assembly operations and machining operations must be analyzed with an integrated model. In this research, a graph-based model is presented to represent the assembly and machining operations in an integrated model. The related operation cost functions are developed to evaluate the costs for the integrated assembly and machining sequences. The integrated sequence planning problem is solved using a genetic algorithm approach with an objective of lowest operation costs. As a result, the assembly operations and machining operations can be planned in an integrated sequence suitable for producing electronic products. The result shows that the developed method using the genetic algorithm approach is efficient for solving the integrated sequence planning problem. Example products are demonstrated and discussed.     

基于模糊评判的机床类型选择及切削参数优化

对影响机床选择的各个因素进行了分析,利用模糊数学理论,根据零件几何特征、机床装夹尺寸、加工范围、加工精度、加工表面粗糙度等因素建立了机床优化选择的理论模型,并利用模糊综合评判法确定了机床选择的隶属度及最大综合评判指标,在创成式CAPP系统中实现了机床的合理自动选择.建立了ABAQUS有限元模型,对机床的钻削过程进行仿真,分别得到了理论上和经验上的切削参数与切削力、切削参数与加工表面残余应力的关系曲线图,从而找到了最优的切削参数.     

面向复杂零件网络化制造的资源优化配置方法

为实现复杂零件网络化制造的资源优化配置,提出一种以零件工艺流程为核心的制造资源优化配置方法。该方法依据零件工艺流程,设计逻辑制造单元和逻辑加工路线,进行基于逻辑制造单元和逻辑加工路线的制造任务分解和描述。为了对逻辑加工路线配置最优的可执行加工路线,以运行成本、时间和加工质量为目标,建立多目标优化模型;在用遗传算法求解模型的过程中,每一代种群,基于影响度因子将运行成本、时间和加工质量的目标特征值矩阵转换为相对隶属度矩阵,进而以每个染色体的距优海明加权距离平方与距劣海明加权距离平方之和最小为准则,求取基于相对隶属度的适应度值。最后,以具体实例证明了该方法解决复杂零件网络化制造资源优化配置问题的可行性与有效性。     

基于多目标满意度的车身轻量化方案优选

为实现车身不同轻量化方案的有效优选,提出了一种基于多目标满意度决策机理的车身轻量化方案优选方法。该方法以不同方案对应性能分析数据为基础,以质量减轻、成本降低和性能改善为目标,估测各目标对方案优选的权重,建立车身轻量化方案优选的多目标优化。基于多目标满意度决策机理,对不同方案进行综合评价,得到的综合满意度最大的方案经验证合格即为优选的轻量化方案。以车身发动机罩板为例,验证了所提方案的有效性。     

STEP-CAPP系统中的非线性工艺设计和工艺优化技术

介绍了STEP—NC应用环境下计算机辅助工艺设计系统的非线性工艺设计的方法和过程,以及如何进行工步序列的有效化。提出了基于精英选择策略遗传算法的工艺优化技术,详细研究了遗传算法在工艺优化中的应用过程。开发了一个STEP—CAPP原型系统,并通过一个实例零件对所提技术和算法进行了演示和仿真,结果表明了该技术和算法的可行性和有效性。     

A structured approach to the automatic planning of machining operations for rotational parts based on computer integration of standard design and process data

The traditional procedure for developing a manufacturing process plan involves a number of interconnected steps beginning with the initial design and culminating in the instructions for the machine that makes the part. When performed manually, the procedure is very tedious, time consuming, and often, inconsistent. This paper presents an alternative method, called the Automated Machining-Operations Process-Planning System (AMOPPS), to automatically generate the process plan and the numerical control (NC) instructions to machine a part that has been previously designed by a computer-aided design (CAD) system. AMOPPS combines preset planning logic and data from three databases (viz., workpiece material, machine tool, and cutting tool) with appropriate data from a CAD database and information from the user about the workpiece to calculate the optimal machining parameters, print a process plan, print the corresponding NC program listing, and provide an on-screen animation of the cutting passes. Although AMOPPS is a prototype, it can be extended by adding other modules, and it does provide a structure through which a fully integrated manufacturing system can be developed.     

集成供应商选择的产品族设计多目标方法

为避免将产品族设计和供应商选择过程分割而导致不可行或非最优的产品开发方案,以及从多角度对产品族优化设计方案进行评估和权衡,提出一个集成供应商选择的产品族设计多目标优化方法,并建立了一个以最大化产品族总利润和最小化产品族生产风险为多目标的优化模型。在该模型中考虑了产品情感属性对消费者选择行为的影响,以更准确地分析消费者的购买偏好、实现产品族的优化过程。针对优化问题,采用非支配排序遗传算法对模型进行求解。通过实际案例说明了所提优化方法和求解算法的可行性和合理性。     

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。     

Application of adaptive neuro-fuzzy inference system and cuckoo optimization algorithm for analyzing electro chemical machining process

Electrochemical machining process (ECM) is increasing its importance due to some of the specific advantages which can be exploited during machining operation. The process offers several special privileges such as higher machining rate, better accuracy and control, and wider range of materials that can be machined. Contribution of too many predominate parameters in the process, makes its prediction and selection of optimal values really complex, especially while the process is programmized for machining of hard materials. In the present work in order to investigate effects of electrolyte concentration, electrolyte flow rate, applied voltage and feed rate on material removal rate (MRR) and surface roughness (SR) the adaptive neuro-fuzzy inference systems (ANFIS) have been used for creation predictive models based on experimental observations. Then the ANFIS 3D surfaces have been plotted for analyzing effects of process parameters on MRR and SR. Finally, the cuckoo optimization algorithm (COA) was used for selection solutions in which the process reaches maximum material removal rate and minimum surface roughness simultaneously. Results indicated that the ANFIS technique has superiority in modeling of MRR and SR with high prediction accuracy. Also, results obtained while applying of COA have been compared with those derived from confirmatory experiments which validate the applicability and suitability of the proposed techniques in enhancing the performance of ECM process.     

面向绿色制造的工艺种类选择及参数优化

绿色工艺规划是实施绿色制造的重要环节,而工艺种类选择是绿色制造工艺规划的首要内容,在对TQCRE(time、quality、cost、resources、enviroment effect)分析的基础上提出了面向绿色制造工艺种类选择的总体要求和五项基本原则,以及种类选择的模糊评判方法,建立了评价指标体系和评价矩阵,并提出了工艺参数优化的数学模型及研究方法,通过数据库设计、软件开发对模糊评判方法和工艺参数优化开发了友好软件操作界面,最终实现了工艺参数优化的最优方案选择。     

Heuristic solution approaches for combined-job sequencing and machine loading problem in flexible manufacturing systems

Job sequencing and machine loading are two vital and interrelated production planning problems in flexible manufacturing systems (FMSs). In this research, attempts have been made to address the combined job sequencing and machine loading problem using minimization of system unbalance and maximization of throughput as objective functions, while satisfying the constraints related to available machining time and tool slots. This research describes two heuristics to deal with the problems. Heuristic I uses predetermined fixed job sequencing rules as inputs for operation allocation decision on machines, whereas heuristic II uses genetic algorithm based approach for simultaneously addressing job sequences and operation machine allocation issues. Performance of these heuristics has been tested on problems representing three different FMS scenarios. Heuristic II (Genetic algorithm based) has been found more efficient and outperformed heuristic I in terms of solution quality.     

Compound feature selection and parameter optimization of ELM for fault diagnosis of rolling element bearings

This paper proposes a hybrid system named as HGSA-ELM for fault diagnosis of rolling element bearings, in which real-valued gravitational search algorithm (RGSA) is employed to optimize the input weights and bias of ELM, and the binary-valued of GSA (BGSA) is used to select important features from a compound feature set. Three types fault features, namely time and frequency features, energy features and singular value features, are extracted to compose the compound feature set by applying ensemble empirical mode decomposition (EEMD). For fault diagnosis of a typical rolling element bearing system with 56 working condition, comparative experiments were designed to evaluate the proposed method. And results show that HGSA-ELM achieves significant high classification accuracy compared with its original version and methods in literatures.     

基于PetriNets和混合遗传算法的双资源JSP动态优化调度

以带有控制器的Petri网为建模工具对柔性生产调度中的离散事件建模,利用遗传算法和模拟退火算法获得调度结果,并通过Petri网进行控制.用于解决作业车间的加工受到机床、操作工人等生产资源制约条件下的优化调度.以生产周期为目标进行的优化调度,将遗传算法和模拟退火相结合.通过多种交叉、变异、概率更新选择、再分配策略等遗传和模拟操作,得到目标的最优或次优解.对算法进行了仿真研究,仿真结果表明该算法是有效性.     

Efficient warpage optimization of thin shell plastic parts using response surface methodology and genetic algorithm

During the production of thin shell plastic parts by injection molding, warpage depending on the process conditions is often encountered. In this study, efficient minimization of warpage on thin shell plastic parts by integrating finite element (FE) analysis, statistical design of experiment method, response surface methodology (RSM), and genetic algorithm (GA) is investigated. A bus ceiling lamp base is considered as a thin shell plastic part example. To achieve the minimum warpage, optimum process condition parameters are determined. Mold temperature, melt temperature, packing pressure, packing time, and cooling time are considered as process condition parameters. FE analyses are conducted for a combination of process parameters organized using statistical three-level full factorial experimental design. The most important process parameters influencing warpage are determined using FE analysis results based on analysis of variance (ANOVA) method. A predictive response surface model for warpage data is created using RSM. The response surface (RS) model is interfaced with an effective GA to find the optimum process parameter values.     

基于人工神经网络的零件特征加工方法获取及其优先权选择

为了获取零件特征的所有可行加工方法,并定量化描述其选择优先权,提出了一种基于人工神经网络的决策方法.在该决策方法中,基于对问题特性的分析,采用均匀设计法选取有代表性的样本集合;为避免常规反向传播算法训练网络时易陷入局部极小值的缺陷,采用可同时调整动量因子和学习率的改进反向传播算法,并用线性回归分析方法加以测试.实例验证了该方法可以有效地获取零件特征的所有可行加工方法及其选择优先权.     

基于遗传算法与有向图拓扑排序的工艺路线优化

针对工艺设计中的工艺路线优化问题,归纳了工步间的基本优先级约束关系。基于约束关系,将整个工艺活动过程转化为工步有向图,工步节点间的拓扑关系以约束矩阵的形式存储。提出了约束矩阵判错的检测方法;建立了工步图的拓扑排序模型。设计了一种随机的深度优先搜索算法对工步图进行拓扑排序,得到全部可行的一定数目初始工艺计划作为遗传算法的初始种群。算法中,提出了基于车间动态资源的加工序列编码策略;定量分析了工艺计划评价准则,采用罚函数的方法将目标函数和约束条件建立成一个无约束的优化目标函数,由此确定了染色体的适应度函数;设计了遗传操作算子(选择、交叉、变异),并通过基于模拟退火机制的精英策略加速算法收敛。最后,通过实例证明了该算法的有效性。     

Developing a model for multi-objective optimization of open channels and labyrinth weirs: Theory and application in Isfahan Irrigation Networks

Finding an optimal design for hydraulic structures and devices, which work together in irrigation networks, can be formulated as a multi-objective optimization problem. In this paper, a novel framework is proposed for simultaneous optimization of an open channel section and a labyrinth weir geometry. A recently proposed optimizer called Multi-Objective Multi-Verse Optimization (MOMVO) algorithm is employed and its results are compared with Pareto Envelope-based Selection Algorithm II (PESA-II) and Non-dominated Sorting Genetic Algorithm II (NSGA-II) using five metrics, including spacing (SP), Maximum Spread (MS), Non-uniformity of Pareto Front (NPF), Mean Ideal Distance (MID), and Coverage Measure (CM). The first objective function is defined to minimize the construction costs per unit length of the open channel, and the second one is to minimize total concrete volume of the labyrinth weir. The results showed significant differences between MOMVO Pareto optimal solutions and the other two algorithms. The least values of SP, NPF, and MID metrics were provided by MOMVO, which meant its solutions had better conditions regarding uniformity and the closeness to the ideal point. To optimize irrigation network as a system, penalty functions were applied to satisfy hydraulic conditions (flow velocity, Froude number, and nappe interference). Results showed that if the proposed model had been employed in Isfahan Irrigation Networks (IINs) design, it would have reduced the construction costs of open channel and labyrinth weir approximately 11% and 74%, respectively. It can be reported that the most cost-effective design has the least channel wetted perimeter, channel cross-section top width, cross-sectional area, and labyrinth apex length; and the highest channel depth, and weir sidewall angles.