Applying CBR to machine tool product configuration design oriented to customer requirements

Product customization is a trend in the current market-oriented manufacturing environment. However, deduction from customer requirements to design results and evaluation of design alternatives are still heavily reliant on the designer’s experience and knowledge. To solve the problem of fuzziness and uncertainty of customer requirements in product configuration, an analysis method based on the grey rough model is presented. The customer requirements can be converted into technical characteristics effectively. In addition, an optimization decision model for product planning is established to help the enterprises select the key technical characteristics under the constraints of cost and time to serve the customer to maximal satisfaction. A new case retrieval approach that combines the self-organizing map and fuzzy similarity priority ratio method is proposed in case-based design. The self-organizing map can reduce the retrieval range and increase the retrieval efficiency, and the fuzzy similarity priority ratio method can evaluate the similarity of cases comprehensively. To ensure that the final case has the best overall performance, an evaluation method of similar cases based on grey correlation analysis is proposed to evaluate similar cases to select the most suitable case. Furthermore, a computer-aided system is developed using MATLAB GUI to assist the product configuration design. The actual example and result on an ETC series machine tool product show that the proposed method is effective, rapid and accurate in the process of product configuration. The proposed methodology provides a detailed instruction for the product configuration design oriented to customer requirements.     

产品数字化设计的分层检索策略

针对机械产品数字化设计过程中设计实例检索困难等问题,在集成粗糙集理论与实例推理各自优点的基础上,提出一种基于粗糙集-实例推理的数字化设计实例分层检索策略,利用粗糙集理论的离散和约简算法实现对免耕播种机特征属性权重的自动计算,利用实例推理理论实现设计实例相似度的计算,建立分层检索过滤等级划分方法,大幅度提升设计实例检索的速度和精度。将分层检索策略应用于免耕播种机数字化设计,成功匹配设计实例,完成Pro/E三维造型。田间试验表明,样机能满足该类型免耕播种机的作业性能要求,验证了分层检索策略的有效性和可行性。     

按单设计型复杂产品多层次配置设计方法研究

在分析按单装配型配置系统不足的基础上,提出一种按单设计型复杂产品多层次配置的设计方法.根据客户需求,基于预定义的产品族平台,针对按单设计型产品不同类型模块特点,应用不同层次的配置规则进行模块的多层次配置,并对配置结果进行校验,得到满足用户需求的产品设计方案,作为订单产品设计的基础.     

机床的总体配置和结构设计(上)

首先从提高机床性能、重视生态环境和关注全生命周期的视角探讨未来机床设计的新方法和机床的结构配置.然后介绍了机床结构优化的基本方法和不同机床结构材料的特点,并从机床结构的质量、刚度和阻尼三者的关系描述了机床轻量化设计的设计流程和应用前景.最后对几种机床结构配置的创新案例进行了分析.     

Generalised design for optimal product configuration

Design of configurable product family or design for configuration has emerged as an efficient tool to deal with the new challenges of a continuous dynamic and volatile market. Design for configuration provides an efficient and effective mean to realise the product variety. This paper tackles the optimal product configuration. The introduction of fuzziness to capture the subjective nature of the design for configuration process, the building of multiple fuzzy models, which correspond to the multiple views of a configurable product, permits to propose the possible physical solutions to configure a product. It corresponds to the consensus problem of design for configuration. The extended problem formulation is the proposition of an optimal product configuration. The optimal solution is searched using p median problem formulation. The proposed approach is validated by the design case study of a configurable product.     

基于知识引导的多视图产品设计检索技术研究

针对传统知识检索方法的不足,提出了基于知识引导的多视图知识检索模型和检索算法,给出了基于知识引导的多视图设计知识检索框架.在此基础上,提出了基于设计情景的知识检索策略,最后通过实例,研究了上述检索方法的实现技术.     

A mechanical structure-based design method and its implementation on a fly-cutting machine tool design

The mechanical structure has a main influence of the machining performance and the servo performance. In this study, a mechanical structure-based design method is presented to design and optimize an ultraprecision fly-cutting machine tool. This method takes full account of the influence of mechanical components on the machining performance and servo performance at the design stage. The effect of the components structure on the roughness of machined surface is discussed, and an optimized structural form of the aerostatic spindle is given. The influence of the mechanical structure on the control system and electronic drives is discussed, and an integrated dynamic design model is built and used to optimize the hydrostatic slide. Furthermore, the impact of mechanical system dynamic performance of the machine tool on the processing topography is analyzed by the finite element model of the machine tool. This method provides a theoretical basis for the design and optimization of mechanical components and machine tools stiffness loop.     

配置产品尺寸参数修改与变型设计方法研究

在大批量定制的产品配置中,有时需要对配置模块进行变型设计或尺寸参数修改,如何快速准确地确定配置模块尺寸之间的相互影响关系,并对配置产品的尺寸参数进行快速准确的修改是配置设计准确性和配置设计效率的关键.将参数化技术和网络理论应用于大批量定制的产品配置领域,在建立产品参数化模型的基础上,建立了配置产品尺寸约束关系网络.提出了基于尺寸参数传递方法的配置产品尺寸参数修改与变型设计方法,开发了与PRO/E集成的产品变型设计模块.最后以联轴器产品为例验证了上述方法的可行性.     

A tolerancing optimisation method for product design

Although extensive research has been carried out in the area of tolerancing techniques for product design, concurrent engineering is still very seldom used in this context. This paper introduces a unique tolerancing method which applies the concept of concurrent engineering. The proposed method essentially allocates the required functional assembly tolerances to the component tolerances by formulating the tolerancing problem into a mathematical model and solving the model using a linear programming approach. The component tolerances are first represented in terms of the process tolerances, assigned by process planners at an early stage of the product design. The objective function of the mathematical model, which is to maximise the residual tolerances of the processes, is then established and the constraints formulated based on the assembly requirements and process constraints. The model is subsequently solved using a linear programming approach. Finally, the proposed method is tested on a practical example.     

基于实例推理的机床模块概念设计系统

介绍了基于实例推理的数控加工中心模块概念设计系统 ,提出了按照模块实例分类和实例参数来描述模块实例的方法 ,论述了数控加工中心机床模块实例的分级描述、编码方案和评价方法。实践表明 ,基于实例推理是一种进行产品系列化再设计的有效推理方法。     

Multi-objective optimization and evaluation method of modular product configuration design scheme

Product configuration is one of the key technologies for mass customization. Traditional product configuration optimization targets are mostly single. In this paper, an approach based on multi-objective genetic optimization algorithm and fuzzy-based select mechanism is proposed to solve the multi-objective configuration optimization problem. Firstly, the multi-objective optimization mathematical model of product configuration is constructed, the objective functions are performance, cost, and time. Then, a method based on improved non-dominated sorting genetic algorithm (NSGA-II) is proposed to solve the configuration design optimization problem. As a result, the Pareto-optimal set is acquired by NSGA-II. Due to the imprecise nature of human decision, a fuzzy-based configuration scheme evaluation and select mechanism is proposed consequently, which helps extract the best compromise solution from the Pareto-optimal set. The proposed multi-objective genetic algorithm is compared with two other established multi-objective optimization algorithms, and the results reveal that the proposed genetic algorithm outperforms the others in terms of product configuration optimization problem. At last, an example of air compressor multi-objective configuration optimization is used to demonstrate the feasibility and validity of the proposed method.     

机床床身结构优化设计方法

结合基于近似模型的尺寸优化及拓扑优化技术,提出了机床床身结构优化设计的策略.首先以床身结构的刚度和基频为设计目标,以床身内部横隔板间距及厚度、垫铁间距为设计变量,通过中心复合设计法生成实验所需的设计变量的样本点,对生成的样本点进行有限元分析得到样本点的响应,借助最小二乘法建立近似模型二阶响应曲面.采用折衷法建立多目标优化模型,并用遗传算法进行求解.在此基础上,采用密度法对床身结构进行拓扑优化.实例计算结果表明,优化后床身质量减轻了4.45%,而刚度提高了5.8%.     

递归化产品配置设计技术研究

运用递归思想,研究了产品配置设计技术.首先定义了产品配置设计单元,并根据产品配置设计单元间的递归逻辑关系,生成了产品配置模板;其次,通过提取配置信息中的新零部件实例和规则知识,实现了配置知识的递归组织;最后在递归定义产品配置设计过程的基础上,分析了配置递归循环的层次性,拓展了产品配置设计外延,实现了递归化产品配置设计技术.该技术在大型电除尘装备的配置设计中得到了实际应用,有效地提高了产品设计效率.     

适于小农机产品快速配置设计的整机模态综合技术研究

为了快速评价产品模块组合的多种配置方案,并且能够通过修改子模块结构及其配置方式,达到满足产品整机动态特性的客户要求,提出了一种基于试验/有限元模态分析模型的产品整机模态综合方法.以小型农业作业机为研究对象,根据小农机的结构特征与工作模式,对其进行了功能模块划分;并根据产品模块的模态试验或有限元模态分析结果,完成了小型农...     

一种面向产品创新设计的知识检索模型与实现

针对计算机辅助创新系统在中文知识检索方面的不足,提出一种基于共指关系扩展的知识检索方法.采用“共指关系索引—检索本体—设计知识”三层映射结构表达设计知识,形成一种以检索本体为组织核心、以共指关系索引为引导的面对面的知识结构体系.通过解析设计者以自然语言表达的检索意图,得到检索动名词词对,利用互信息技术计算概念术语间的相似度权重,匹配到符合检索意图的功能本体,调用已构建好的功能基索引检索设计知识.通过开发的知识检索原型系统中的检索示例验证了该方法的可行性.     

一种FANUC 0i系统的机床分期付款控制方法

机床销售过程中常采用分期付款方式。文章给出了一种包括系统时间保护,预报警和逾期报警、密码解锁和PMC程序保护在内的控制方法,满足了机床厂家FANUC 0i系统机床分期付款功能要求。     

一种新的机床位置误差灵敏度分析方法

本文提出一种新的机床位置误差灵敏度分析方法。首先基于多体理论和齐次变换矩阵建立了五轴龙门机床位置误差模型。其次通过截断傅里叶技术来表征与位置有关的几何误差参数,每个误差参数对位置误差的灵敏度值可表示为其傅里叶幅值平方。然后归一化处理,关键的几何误差参数为第2,3,8,15和26项误差。通过与传统的Sobol法对比,仿真结果表明两种灵敏度分析方法辨识的关键几何误差相同且灵敏度值相近。此外,本文提出的灵敏度分析计算效率优于传统Sobol法。最后为了验证关键几何误差的有效性,提出了一个关于机床关键几何误差的补偿实验。实验结果表明,补偿关键几何误差后机床的加工精度提升了48%。因此,本文提出的机床位置误差灵敏度分析方法是可行的和有效的。     

一种基于DCSP和CBR的产品配置方法

为提高客户需求表达的正确性、利于企业运用已有案例进行新产品的设计,提出一种基于动态约束满足问题和实例推理相结合的产品配置设计方法。将配置问题转化为动态约束满足问题,获得规范化的客户需求信息。通过基于实例推理的方法,将这些信息在实例库中进行检索,获得所需的相似实例。在约束求解时通过分层约束的方法来缩小搜索空间,在实例查询过程中通过属性相似度的计算来确定相似实例,并设计了案例搜索流程。最后给出一个推理求解的实例。     

大型精密机床设备基础设计

简述大型物密机床设备基础的计算理论和方法。实践证明该方法经济且能满足工艺要求。