产品可适应设计评价的信息熵方法

随着用户对产品的功能、质量、成本、个性化以及环境友好性等方面的需求日益提升,制造企业必须更加即时、高效地响应不断变化的市场需求.可适应设计作为一种新型的设计范式,可通过设计过程的综合优化来满足产品生命周期内用户、制造企业和社会的需求,以提升经济效益和环境效益等.为了提高产品设计的可适应性,需对可适应性进行量化的科学表达...     

Analysis of dimension data transfer process in product change design

In order to improve product design efficiency, the dimension data transfer process in the process of change design is discussed from two aspects: the propagation of dimension change between the parts and between the key structures inside the part. Firstly, the basic logic structure of product dimension correlation design was analyzed, and the change propagation logic meta-model was established. Then, by analyzing the assembly correlation and dimension correlation among the parts, the correlation path among the parts in assembly and the propagation model of dimension correlation change were established. Taking the change part as the research object, according to the connection and constraint relationship between the internal dimensions of the part, the change propagation path for the internal dimensions of the part was established based on the part modeling process, and the dimension change propagation of the key structures inside the part was completed. Based on the above process, the whole change propagation and data transfer process analysis from the change source to the part and to the specific dimension inside the part were completed. Finally, the validity of the proposed method was verified by an example of a veneer reeling machine. The results show that this method can provide a new idea for the propagation of product dimension change, and provide a theoretical basis for improving product design efficiency.     

基于信息熵的转子动力特征分析与诊断方法研究

针对转子系统运行过程中的非线性、耦合性、非平稳突变性等复杂特征,提出基于信息熵特征提取方法,将转子系统动力分析与参数识别方法有机结合,分析转子典型故障——裂纹、碰摩及裂纹碰摩耦合等不同状态下响应参量的信息熵特征及变化规律,并构建小波神经网络模型实现转子系统故障状态诊断。通过对转子系统实测信号的分析诊断,验证理论方法的有效性。     

基于性能的耐久性损伤RC构件时变抗震设计方法研究

采用基于性能的抗震设计方法,考虑典型耐久性环境的影响,以及时变地震作用,探讨基于性能的耐久性损伤钢筋混凝土构件时变抗震设计方法。通过构件变形能力进行量化处理,建立了使用年限内典型耐久性环境下,构件破损指标、相对受压区高度、配箍特征值及曲率延性的量化关系式。对耐久性退化钢筋混凝土构件抗震设计时,应根据使用年限及耐久性环境,通过性能目标来调整构件设计要求,建议对规范配箍特征值、最小配筋率及相对界限受压区高度等抗震设计指标进行调整。以一般大气环境为例,给出了典型耐久性环境下,构件抗震设计时的最小配筋率和最小配箍率调整系数,以及不同抗震等级下的相对受压区高度在不同设计使用年限内的限值要求。     

产品参数化变更设计的时间评价

产品零部件之间存在着复杂的信息依赖关系,对产品局部的改动可能影响到整个产品的设计周期,因此评价产品设计变更的消解时间以便决定合适的产品开发策略显得极为重要。在产品参数化设计进程模型的基础上,提出了产品设计任务信息依赖度的概念和计算方法,分析了交互依赖、串联、循环等五种任务关联模型的设计变更时间计算方法,以减速器为设计实例说明了参数设计变更的时间评价方法。     

产品设计中人机尺度关系量化评价的研究

针对产品设计中人机尺度关系评价,提出了一种评价体系及其量化方法,定义了4种基本的评价类型,提出了人体关节不舒适度因子的概念和计算方法,实现了对人机尺度关系状况的总体和局部的数学描述.对改进产品设计,提高产品的宜人性有明显作用.     

一种新的非线性系统脊骨线提取方法

脊骨线对于非线性系统的判断、描述和参数识别,具有重要的意义;而现有的脊骨线提取方法大多理论上较为复杂,且有局部线性化误差较大、数据波动剧烈等问题,限制了工程应用。提出一种新的非线性系统脊骨线提取方法,该方法利用非线性系统自由振动响应的一次谐波分量,计算谐波信号峰值点的瞬时频率,可以方便地提取脊骨线;这种新的非线性系统脊骨线提取方法理论明确、简单,计算方便,易于工程应用。通过三个数值算例说明了该方法的有效性,同时将此方法应用于非线性描述,并综合讨论了非线性描述的几何方法;并基于此方法进行了非线性系统参数识别,取得了良好的效果。     

同异反产品设计方法

 在产品设计中，领域专家的经验知识和人类创新思维的信息交合对于最终产品设计的成功与否至关重要．面向产品设计的各个过程，利用集对论的系统分析方法从联系的角度实现了设计信息的整体处理．并在此基础上，提出一种新的产品设计方法—— 同异反设计法． 该方法在设计过程中较好地利用了领域专家的经验知识，体现了“以人为本”的设计思想，实现了知识的重用．最后，针对面向市场的产品设计的3个阶段初步说明其在产品设计中的应用．     

CONDENSE: A concurrent design evaluation system for product design

In dealing with the issue of integrating design and manufacturing, concurrent design evaluation plays an important role. This paper presents a concurrent design evaluation system (CONDENSE) developed to help product designers in evaluating possible design solutions and design alternatives during the early stage of design. It consists of two important functions: a qualitative aspect evaluation applied during the stage of searching for combinations of solution principles to help determine the design specifications, and a quantitative aspect evaluation applied to provide information on performance, assemblability, manufacturability and costs to facilitate design selection. The framework of CONDENSE is based on a blackboard architecture that requires the classification of knowledge into appropriate knowledge sources. As design data are interrelated and may have uncertainty, a graph decomposition algorithm is used in constructing the knowledge sources, and a linguistic evaluation module is integrated with the qualitative aspect evaluation subsystem to deal with data uncertainty. The proposed system has been validated with respect to the design of golf club heads. The results, which have been validated by experienced designers, are promising and can contribute to the speed-up of design and development, improvement of design quality and facilitation of design selection.     

基于小波能谱和小波信息熵的管道异常振动事件识别方法

提出了基于小波能谱和小波信息熵的油气管道异常振动事件识别方法。基于Mach-Zehnder光纤干涉仪原理的分布式光纤油气管道安全监测系统实时检测管道沿途振动信号,对测量的时间序列进行小波变换,根据小波系数计算小波能谱与小波信息熵,通过小波能谱和小波信息熵值两种测度识别不同的管道安全异常事件。港枣线成品油管道的现场实验结果表明,该方法可以快速有效地识别管道周围发生的泄漏及其他异常情况,其总体识别准确率达到98.5%,有效降低了误报警率,具有较强的在线工况识别能力。     

反拱形水垫塘底板上举力特性的试验研究

以实际工程高拱坝水垫塘底板稳定性研究为背景,阐述了反拱形水垫塘底板上举力的成因,建立了考虑板块下表面压力沿缝隙传递的失稳区板块专门水力学模型测量板块的上举力,在模型试验结果的基础上,分析了底板上举力的分布规律。给出的最大上举力经验公式,可用于工程设计中反拱结构的水动力荷载计算。     

基于多尺度降维的柴油机信号信息熵增强方法

针对柴油机曲轴轴承磨损故障信号特征微弱,易被噪声湮没且不同故障程度信号较难区分的特点,提出了一种基于压缩小波和局部保持投影的柴油机信息熵增强方法。利用压缩小波对信号多尺度重构减弱噪声干扰,通过局部保持映射对多尺度信号进行降维,消除冗余信息并增强信号的冲击特性,最终以时域、频域以及时频域的三种信息熵表征信号特征。仿真和实例信号表明,该方法对故障信号特征增强明显,依据信息熵值实现了曲轴磨损状态的分类识别。     

面向轨道车辆抗蛇行振动的磁流变脂阻尼器设计与台架测试

针对磁流变液阻尼器存在磁场利用率不高和磁流变液沉降导致控制特性劣化的问题,提出一种基于多级径向流动模式的磁流变脂阻尼器方案,将磁流变脂的多级径向流动分解为源流与汇流的对称组合,建立了磁流变脂径向流动的分析模型。利用磁流变脂微单元平衡得出了磁流变脂尊静态径向流动微分方程,采用磁流变脂双粘度本构模型和无滑动边界条件,导出了磁流变脂径向流动速度分布函数和径向压力梯度分布函数。绘制了磁流变脂在不同半径处流动速度分布图,得到了磁流变脂阻尼器的阻尼力计算方法。按照轨道车辆抗蛇行减振器的技术要求,设计制作了基于多级径向流动模式的磁流变脂阻尼器样机,利用J95-I型油压减振器试验台对其示功特性进行了测试,结果表明在不同激励电流下的磁流变脂阻尼器理论示功特性与实验示功特性能较好吻合。     

移动荷载作用下结构损伤的近似熵分析

当移动荷载接近或远离结构损伤部位时,结构的振动响应的幅值和非线性特征会发生变化,可以从中提取有关结构损伤的信息;近似熵可以表达一个时间序列的复杂性和内在模式。用移动荷载作用于结构上,对其振动响应数据进行近似熵计算,提取其非线性特征值,进而用神经网络进行结构损伤模式识别。通过一个移动荷载作用下简支梁的计算实例考察了这一方法的有效性。移动荷载的作用,使得损伤造成的结构非线性特征更加显著;研究、计算与实测案例表明近似熵能够有效地表征信号的非线性程度,而且对噪声干扰的敏感度低,可以作为神经网络模式识别的特征向量。     

Using product family evaluation graphs in product family design

Product family design and platform-based product development have garnered much attention. They have been used to provide nearly customised products to satisfy individual customer requirements and simultaneously achieve economies of scale during production. The inherent challenge in product family design is to balance the trade-off between product commonality (how well the components and functions can be shared across a product family) and variety (the range of different products in a product family). Quantifying this trade-off at the product family planning stage in a way that supports the engineering design process has yet to be accomplished. In this paper, we introduce a graphical evaluation method, the product family evaluation graph (PFEG), that allows designers to choose the ‘best’ product family design option among sets of alternatives based on their performance with respect to an ideal commonality/variety trade-off determined by a company's particular competitive focus, and guides designers towards a more desirable trade-off between commonality and variety in an existing product family. Two necessary supporting pieces for developing the PFEG are also proposed. One piece is the development of commonality and variety indices to quantitatively capture the degree of commonality and variety in a product family and its functions and components. We introduce two sets of commonality and variety indices–the CDI (commonality versus diversity index) for commonality (CDI_C) and variety (CDI_V), and the CMC (comprehensive metric for commonality) for commonality (CMC_C) and variety (CMC_V)–to achieve this. The other supporting piece is the development of a quantitative representation of the ideal trade-off between commonality and variety in a product family, known as the commonality/variety trade-off angle α, based on the elements that characterise a company's competitive focus and their industry-wide competitors. A linear regression model is used to link the qualitative competitive focus to a quantitative engineering perspective, and then to estimate the ideal trade-off angle. The commonality/variety trade-off angle can then be applied to the PFEG to help designers evaluate a product family or compare product family design alternatives. Most importantly, the PFEG is not just the graph of the two sets of indices; it is the representation of the commonality/variety trade-off relative to the desired competitive focus. Four families of power tools are used to illustrate how the computation of such indices supports product family design evaluation in the PFEG. In this paper, we only use the CDI in the example application, but the CMC can be computed using the same approach.     

机床直线轴重复定位精度三维评价方法研究

重复定位精度是机床的一个重要性能指标，会直接影响加工产品的质量一致性。现有以直线轴运动方向的位置偏差作为评价指标的一维评价方法已经不适用于精密机床重复定位精度的评价。为了更全面地评价机床直线轴重复定位精度，提出了机床直线轴重复定位精度的三维评价方法，以球概率误差半径作为评价指标，将一维定位评价扩展到三维空间评价。首先，以卧式加工机床为例，通过齐次坐标变换建立了运动件单轴和机床的重复定位精度的数学模型，对现有一维评价方法的局限性进行分析。其次，基于卡方分布的性质，对球概率误差半径的计算过程进行简化。最后，通过简化的球概率误差半径计算方法对机床直线轴重复定位精度进行评价。以精密卧式机床的工作台为研究对象，通过实验对一维评价方法和三维评价方法进行了对比，结果表明，以球概率误差半径为评价指标的三维评价结果与定位点空间分布的离散程度基本一致。采用三维评价方法可以使机床重复定位精度的评价更加全面，可为机床整体性能的提升提供更可靠的理论指导。     

面向多维意象的产品设计方案评估研究

用户的感性诉求日益获得产品设计师和企业决策者的关注,为了使产品开发人员在开发新产品时能满足用户多维复合的感性诉求,提出一种结合熵处理、灰色关联分析和逼近理想解排序(technique for order preference by similarity to an ideal solution,TOPSIS)的方法,用于产品设计方案的评估。首先,在运用K-mean聚类分析和因子分析方法分别获得符合用户感性认知的典型样本和典型感性意象的基础上,运用语意差异法获得用户-意象初始评价值;其次,应用信息熵计算评估指标的权重;最后,采用灰色关联分析与TOPSIS相结合的方法实现用户多维意象特定要求下对备选设计方案的排序优选。以3D打印机设计方案优选为例,验证了方法的可行性。研究结果表明,该方法符合用户实际的复杂认知,能有效客观地对产品设计方案进行评估和优选,具有实际应用价值和指导作用。     

Research on solving method of product ergonomics problem based on virtual simulation and TRIZ

In order to quickly and accurately solve the ergonomics problems and improve the human-machine performance of products, a solving method of product ergonomics problem based on the virtual simulation and TRIZ (Teoriya Resheniya Izobreatatelskikh Zadatch) is proposed. Firstly, the evaluation of human-machine performance for the product was carried out by the virtual simulation tool, and the product area correlation was performed based on the obtained human body data to determine product areas with ergonomics problems. The root causes of product ergonomics problems were found by using the functional model and causal analysis. Then, according to the product ergonomics design cases and expert questionnaire survey results, a correlation table of TRIZ standard engineering parameters and ergonomics design criteria was constructed, and design schemes that could solve the product ergonomics problems were obtained through the correlation table and conflict analysis tool of TRIZ; based on the concept of ideality, the ideality evaluation method of product human-machine performance was proposed and the evaluation for obtained design schemes was carried out to determine the best design scheme. The proposed method was applied to solve the ergonomics problem of electric jig saw, which not only solved the problem quickly,but also improved the usability of electric jig saw. The results show that the proposed method can improve the innovation design efficiency and the ergonomics performamce of products, which provides a new idea for solving product ergonomics problems.     

基于排列熵理论的非线性系统特征提取研究

提出一种基于排列熵及其改进理论的伪相平面法,从而可以提取非线性系统中的微弱周期信号特征。通过选择合理的时间延迟和嵌入维数,对Duffing系统的响应信号进行相空间重构,得到一次排列熵和二次排列熵。随后将位移激励、一次排列熵和二次排列熵作为数据集,组成位移激励-一次排列熵和位移激励-二次排列熵两种伪相平面。通过将这两种方法与传统的相平面法、频谱分析和排列熵、排列熵谱、二次排列熵、二次排列熵谱的提取效果进行对比,验证了该方法的合理性。研究表明该方法能够对非线性系统中的微弱周期信号特征进行提取,取得了较好效果。     

基于熵技术的矿山安全模糊综合评价

根据矿山安全评价所存在的模糊性和随机性的特点,在建立多级模糊综合评价的指标体系的基础上,借用信息论中熵的概念计算客观权重的方法,运用模糊数学理论,建立二级模糊综合评价模型,提高了矿山安全现状评价的客观性和科学性,具有一定的工程实际应用价值.