Approximate life cycle assessment of product concepts using multiple regression analysis and artificial neural networks

In the early phases of the product life cycle, Life Cycle Assessment (LCA) is recently used to support the decision-making for the product concepts, and the best alternative can be selected based on its estimated LCA and benefits. Both the lack of detailed information and time for a full LCA for a various range of design concepts need a new approach for the environmental analysis. This paper explores a new approximate LCA methodology for the product concepts by grouping products according to their environmental characteristics and by mapping product attributes into environmental impact driver (EID) index. The relationship is statistically verified by exploring the correlation between total impact indicator and energy impact category. Then, a neural network approach is developed to predict an approximate LCA of grouping products in conceptual design. Trained learning algorithms for the known characteristics of existing products will quickly give the result of LCA for newly designed products. The training is generalized by using product attributes for an EID in a group as well as another product attributes for the other EIDs in other groups. The neural network model with back propagation algorithm is used, and the results are compared with those of multiple regression analysis. The proposed approach does not replace the full LCA but it would give some useful guidelines for the design of environmentally conscious products in conceptual design phase.     

Design of a vibrating MEMS gyroscope considering design variable uncertainties

Recently, several micro electro-mechanical systems (MEMS) such as a MEMS gyroscope have been developed by using micro manufacturing technologies. Micro scale products, however, usually have a relatively large manufacturing uncertainty compared to normal macro scale products. It is quite expensive to lower the variance of material properties as well as the geometric properties of a micro scale product. The material and geometric uncertainties caused by a micro manufacturing process inevitably lead to the uncertainty of the product performance. Therefore, to achieve a reliable design of a product, the performance uncertainty of the product, which is often expressed by the variance or the standard deviation, needs to be estimated in a reliable way. In this paper, the equations of motion of a MEMS gyroscope model are derived to analyze the system performance indices (sensitivity and bandwidth). The mean values of the design variables are determined from the requirements of product size, maximum vibration amplitude, and driving frequency. Then the standard deviation of some critical design variables is determined from the performance requirements. Finally, a statistical analysis procedure based on sample statistics is proposed to estimate the confidence interval of the performance index statistics.     

A lightweight suction gripper for micro assembly

Assembly is a crucial part in the realization of a product. Compared to assembly in the macro world, assembly in the micro world is influenced by scaling effects. These include surface forces, high requirements on placement uncertainty and small product dimensions. Conventional high-speed assembly in many cases utilizes suction grippers. However, their large moving mass results in high collision forces during product placement. Therefore, they are unsuitable for assembling micro products. This paper will discuss problems during assembly in the micro world with an emphasis on forces during the assembly process. A new design is proposed for a gripper with a moving mass less than 1 g for a pick up needle with a 6 mm diameter. In the design friction and hysteresis are neglectable. The paper focus is on gripper design, realization and experimental results.     

闭环物流宏微观协同决策模型

在原有的正向物流基础上,将逆向物流并入其中,构成一个闭环的物流网络。以总闭环物流运输成本、库存成本、惩罚成本和建设成本之和最低为目标,建立闭环物流网络数学规划模型,实现了在闭环物流系统宏观总需求前提下的微观物流计划安排,并利用分支定界法解出其最优解。实例分析结果表明,宏微观协同决策模型较好地补充了传统闭环物流模型的静态单目标单产品问题,可以解决动态多目标多产品的决策问题,实现了供应链设计宏观战略和微观战术的结合。     

PRODUCT DATA PREDICTION WITH UNCERTAINTY IN PRODUCT LIFE CYCLE DESIGN

Various kinds of data are used in new product design and more accurate data make the design results more reliable. Even though part of product data can be available directly from the existing similar products, there still leaves a great deal of data unavailable. This makes data prediction a valuable work. A method that can predict data of product under development based on the existing similar products is proposed. Fuzzy theory is used to deal with the uncertainties in data prediction process. The proposed method can be used in life cycle design, life cycle assessment (LCA) etc. Case study on current refrigerator is used as a demonstration example.     

颗粒增强复合材料弹性结构的双尺度有限元分析

颗粒增强方法是实现材料高性能化的重要手段。预测颗粒增强复合材料的细观结构与力学性能的关系是实现材料增强增韧的基础。为更好地分析、设计和优化复合材料,需要引入多尺度计算模型来考察细观结构对宏观力学性能的影响。基于均匀化理论,采用Voronoi有限元法对颗粒增强复合材料进行细观数值模拟,从而预测材料的宏观等效弹性常数,并直接得到材料的细观应力场。在细观尺度,首先假设满足平衡条件的应力场,采用Voronoi应力单元建立余能泛函并得到细观控制方程,最终形成可直接求解的线性代数方程组,从而求得应力系数并得到细观应力场。在宏观尺度,利用商业有限元软件ANSYS来进行宏观结构分析。通过均匀化方法求得弹性模量的宏观平均值,将其输入ANSYS系统即可进行计算,由此把宏细观两个尺度耦合起来,可以对颗粒增强复合材料构成的结构体进行有效的力学分析。     

绿色产品的基本概念与评价方法

首先提出了绿色产品的基本定义及其三个基本要素 ,即技术先进性、绿色性、经济性。然后详细讨论绿色产品寿命周期分析的五个阶段及其有关的数学方法 ,最后以低密度聚乙烯为例进行了LCA方法的应用分析。     

面向汽车企业的PLM知识管理

从产品生命周期管理PLM（Product Lifecycle Management）的本质出发,分析了PLM知识管理在汽车企业重要性,提出了一种简单的PLM知识管理模型（TELL＆ASK模型）并简要介绍其关键技术及PLM知识管理系统中的几个主要研究问题。该模型旨在简化产品生命周期各阶段的信息流,使正确的知识能在正确的时间传递到正确的地点被正确的用户应用;论文最后给出实例。     

Development of virtual reality-based universal design review system

When designing universal design products or their interfaces, it is necessary to have knowledge about the environment in which the target product is going to be used. Product development should consider the interaction between the envisaged product or a demo product with the same functions on the one hand, and the users on the other, as well as observing the everyday activities of typical users, understanding the procedures and methods for using the product and subsequently pinpointing the areas which are problematic or in need of improvement. To evaluate whether the designed product is easy to use, and to improve its usability, it is also essential to record the perceptions of the people, the movement characteristics, the operability, any mental or physical stress, and so on. There is a need for products and environments which are easily applicable to various people and utilizational setups. In this paper, we present the development of a tangible design review system which makes use of virtual reality technology to display a close model of the actual product, making readily available not only visual information but also the perception of volume and weight through the fusion of kinesthetic information, enabling many people to communicate easily while experiencing this virtual reality. Furthermore, the design review of universal design products which makes use of this system will be discussed.     

Design for pressure die casting—A DFM example

The designer makes many maufacturing decisions that influence the production cost and the quality of the product. It is therefore important to ensure that the designer has a good foundation for these decisions. When talking DFM, it is important to realise that there are large differences between companies in how product design and production are carried out. The objective of the present research is to investigate and to improve the communication flow between design and production for a selected area: pressure die casting. This area is characterised by many subcontracting producers, and design and production are therefore often placed at different geographic locations. This makes an efficient communication flow even more important and it also makes the communication interface more visible. This paper discusses how manufacturing considerations are made in different design situations and how information supporting tools should be formed accordingly. Results from an investigation of DFM in a number of pressure diecasting companies and companies that design products for pressure die casting are presented. The investigation focuses on the type, the detailing level and the accessibility of the part information passing from design to production and on the manufacturing guidelines and suggestions coming from production to design.     

基于任务结构的产品设计知识模型研究

在对产品设计知识应用特征分析的基础上,研究了支持设计知识建模的任务结构模型及建议－评估－修改方法,和支持标准型、变型及系列产品设计知识的统一产品设计任务分解结构（用树状与或图表示）。提出了4层结构的产品设计知识模型,实现了多种知识表示方法下复杂产品设计知识的分层与分类表示。为解决设计知识获取问题,设计了产品设计知识获取工作表,对设计知识进行了规范说明和瓶颈分析。最后,建立了路面摊铺机设计知识模型。     

大行程高精度驱动系统的研究

首先对大行程高精度驱动系统结构研究进展进行介绍和评述,其次针对目前大行程高精度宏微两级定位系统结构复杂,体积大,驱动控制困难等问题,提出研究具有宏微双重运动功能的单一驱动结构将是大行程高精度驱动定位系统的发展方向;指出将超声电机与压电微驱动器结合成为单一驱动器将是大行程高精度驱动系统的一个发展方向;最后对单级超声电机宏微驱动系统建模方法、位置控制策略的研究进展进行了综述,指出了单级宏微驱动的超声电机研究的主要难点。     

生命周期评价中的时间折扣研究

生命周期评价(Life Cycle Assessment,LCA)是评价产品生命周期环境影响和资源消耗的有效工具。但是现行的LCA并没有考虑清单数据的时间差异,导致了生命周期影响评价结果的不准确性。研究了LCA中的时间差异和生命周期排放模式,引入生命周期平均排放速率函数,以连续排放的模式代替现有研究的脉冲排放模式。在此基础上运用一级衰减模型建立了LCA中的时间折扣计算方法。最后,以国内某企业生产的洗碗机产品进行实例研究,说明LCA时间折扣的应用,表明应用时间折扣方法后CO2排放的变化。     

Configuration-oriented product modelling and knowledge management for made-to-order manufacturing enterprises

In made-to-order (MTO) manufacturing enterprises (ME), product architectures are usually modularised and components standardised. Product configuration is a key technology for order realisation in MTO–ME and is a typical knowledge-based application. Through a configuration process, product modules or components are selected and assembled according to customer requirements. Product configuration relates to a great deal of knowledge that represents complexity relations among components or modules, such as configuration rules and assembly constraints. Traditional product modelling techniques are focused mainly on physical product modelling and geometric representation, which makes them insufficient to help in the product configuration process. This paper discusses configuration-oriented product modelling and knowledge management for MTO–ME. A general process of product configuration modelling is proposed. The configuration model represents a product family from which a specific configuration solution or product variant can be derived. Actually, configuration modelling is a process which captures and represents product knowledge. In this paper, product knowledge is organised and managed through a knowledge component (KCOM) that includes configuration rules and constraints. A KCOM-based product knowledge representation model is presented. Finally, a PDM system is extended to support product modelling and knowledge management for MTO configurable products .     

宏/微双重驱动技术的研究和应用现状

宏/微双重驱动技术因具备大行程、快速响应、高精度定位等特点,近年来在微操作领域得到了广泛的应用.总结了目前常用的宏/微双驱动的宏、微定位部件,并分析了它们各自的优缺点及使用范围;并介绍了常见的宏/微双重驱动系统的集成方式,以及国内外这方面研究取得的成果.为即将从事这方面研究的人员提供了很好的参考.     

Performance evaluation of manufacturing systems based on dependability management indicators—case study: chemical industry

Dependability is a key decision factor in today’s global business environment affecting product cost and process. Dependability reflects user confidence in fitness for use by attaining satisfaction in product performance capability, delivery, service availability upon demand, and minimizing cost. The main objective of this study is to develop an integrated approach for evaluation of manufacturing systems based on dependability indicators for conducting a better dependability management system (DMS) through integration of the principal component analysis (PCA) and the data envelopment analysis (DEA). To achieve the objective of this study, an industrial sector—chemicals and chemical products in Iran—is selected as the case of this study in accordance with the International Standard for Industrial Classification of all economic activities (ISIC). Firstly, we define dependability indicators, for both inputs and outputs, based on IEC 60300. Due to the extra amount of indicators, we utilize a hierarchical structure to cluster the indicators for an easier analysis. Secondly, for reducing the number of some variables, we apply pair-wise comparison to assign weights and to unify the related sub-criteria to one main criterion. Finally, an integrated DEA–PCA approach is employed to assess the most and the least dependable units and to find critical indicators in macro and micro levels in order to make policy for implementation of DMS in manufacturing systems.     

现代设计与知识获取

一个新产品的竞争能力在于产品设计中新知识的含量，在现代设计技术中，必地为开发一个新产品获取新设计知识的能力的发展给予更多的重视，本文讨论了设计知识的结构，获取设计知识的信息来源和处理技术，建议在信息科学，知识工程和计算机技术的基础上发展一个设计知识获取系统和并行设计环境以加速我国制造工业现代化的步伐。     

拉伸变形过程中磁记忆效应及微观表征的试验研究

针对金属磁记忆技术在工程应用中磁信号的定量问题,从微观视角探索了宏观磁记忆信号与金相组织的关系。在Q235材料静载拉伸过程中不同变形阶段磁记忆信号特征分析的基础上,通过制备标准拉伸试样进行拉伸过程中磁记忆信号与微观金相组织的同期观测,研究了宏观上磁记忆信号特征和微观、细观层面上的金相表征之间的对应关系。结果表明：金属材料内部的磁场分布变化与应变变化有关,金属材料内部磁场信号随着变形不均匀而产生磁场分布不均匀的变化。     

基于知识的大规模定制产品可拓配置设计

针对现有产品配置设计方法中对客户性能需求研究的不足,提出了基于知识的大规模定制产品可拓配置设计理论与方法.通过分析产品设计过程中的信息处理,明确了基于知识的设计系统开发思路,应用物元理论与可拓学方法,对大规模定制的典型机械产品进行基于数据库的可拓分类知识挖掘,建立满足产品个性需求性能的可拓配置变换规则、关联函数及与之对应的产品可拓配置集等,并将其有效地应用到单体液压支柱的个性化配置设计中.应用实例表明:该方法不仅能快速满足大规模定制设计的个性化要求,而且能为计算机参与解决配置设计矛盾问题提供一种可行的途径.     

大范围工件寻位问题的递阶求解方法

为解决大范围工件寻位这一难题,研究出宏微观相结合的递阶寻位方法。该方法利用先进智能传感技术,以无接触方式快速获取工件宏观位姿信息,并以此引导微观精确测量过程获取工件关键特征的精确信息,最后通过基于现代数学理论的快速算法准确求解出工件的实际状态,实验结果表明,所提出的方法具有良好的应用效果。