CAPP中基于本体和CBR技术的数据挖掘建模研究

研究了基于本体的数据挖掘事例库的构建、两级事例检索策略(以基于本体的语义理解为第一级事例检索,以数值相似度计算为第二级事例检索)、语义相似度计算方法、数值相似度计算方法等技术,将本体技术和CBR技术集成起来构建了基于本体的CBR系统,并通过大量实验验证了其有效性。     

领域本体组织的自助式零件库

针对目前已有基于Web的开放零件库在使用上自主性和自助性的不足,建立了一套领域本体组织的、基于HTML5技术的开放式零件库系统,该系统能够提供自助零件发布、零件语义信息检索、跨设备跨平台的零件数据浏览等功能。建立了领域本体,负责组织整个零件库资源,并使用推理机对该领域本体进行概念一致性检查;借助可扩展标记语言的转化,实现供应商的自助零件信息发布和本体属性及实例的维护;利用语义相似度算法扩展用户检索关键字,得到符合意图的零件检索结果。整个系统利用HTML5技术实现,支持在不同移动设备的不同操作系统中进行无插件的查看和操作,同时借助异步JavaScript与可扩展标记语言技术实现自助式零件上传和交互式零件选型。实现了领域本体组织下的跨平台零件库原型系统,有效提升了开放零件库使用的自助性和灵活性,对语义相似度算法的实验证明了领域本体定义的合理性,可以满足语义检索的扩展性要求。     

基于语义情境的机械设备拆装增强现实诱导

针对机械设备拆装诱导中人机交互性差、诱导信息过载等问题,提出基于装配语义图模型的拆装子情境感知方法。分析了机械设备拆装语义的组合性特点,建立了零件类型本体层次树模型、连接类型本体层次树模型和产品装配语义图模型;在上述模型的基础上,提出基于装配语义图模型的拆装情境相似度计算方法;应用该子情境相似度方法,提出基于语义情境的操作者知识经验模型,实现了对拆装诱导信息的检索和筛选,提高了诱导信息的针对性和系统的人机交互性。     

面向创新设计的工艺设计知识模型及检索方法研究

在工艺设计领域,为扩展创新设计知识空间,提出面向创新设计的工艺设计知识模型及检索方法。在讨论工艺知识特征及知识表达方法的前提下,针对工艺知识特点及领域范围,提出基于目标的工艺设计知识构成要素、基于本体的工艺知识管理逻辑架构,建立工艺设计知识组织模型,以"功能+流+案例"为规则构建作用本体及流本体,并完成对抽象流、工件特征以及制造资源等功能的本体化表达。通过结合创新方法与工艺案例的方法,提出面向目标的工艺设计知识语义模型。基于对功能和流相关本体词汇同位及上下位扩展的研究,利用扩展算法、知识语义检索、分词模型等方法提出可满足创新设计目标的工艺知识检索模型,并建立了原型系统。     

面向实例推理的产品设计本体建模研究及应用

分析现有基于实例推理的产品设计系统,针对其缺乏对实例功能、行为等描述的缺点提出面向实例推理的产品设计本体模型,并利用本体技术建立基于实例推理的产品设计实例本体及产品设计实例本体模型.依照产品设计特点研究产品设计实例本体模型的重要性质,依据实例推理的产品设计给出基于本体的产品设计实例本体检索机制.在检索中利用本体模型的EDCOM数组,通过相似度算法进行匹配找出合适的产品设计实例,在本体模型库维护中给出本体模型的集成算法.最后以汽车零部件企业为实例,并利用本体技术开发了基于实例推理的产品设计原型系统,通过设计系统的产品设计要求、检索实例等功能模块实现了基于实例推理的产品设计.     

基于扩展特征树的三维CAD模型相似评价

针对现有的三维CAD模型检索算法难以有效捕捉零件中包含的工程语义、无法满足设计重用需求的问题,提出一种基于扩展特征树的三维CAD模型相似评价方法。以三维CAD模型的边界表示为输入,通过交互定义设计特征及自动识别特征间关系的方法建立其扩展特征树;综合扩展特征树及其特征的几何属性表征给定三维CAD模型,并通过非精确的树匹配算法及一种自适应的权重分配方案实现三维CAD模型间的相似评价。理论分析及实验结果表明,该算法能够快速检索到相似的三维CAD模型,其检索结果较好地反映了模型的设计语义,满足设计重用需求。     

三维CAD模型检索驱动的快速数控编程方法

为了实现对已有零件数控(Numerical control,NC)工艺设计成果的有效重用,提高NC加工工艺编制效率,提出一种三维CAD模型检索驱动的快速NC编程方法。通过建立一种以制造特征为核心的工艺信息模型,实现对已有零件NC工艺设计成果的有效表征;引入基于内容的三维CAD模型检索方法,从工艺信息模型库中检索出具有相似制造语义的制造特征,实现零件特征级制造语义层面的相似性评价;根据特征的相似度值选择不同的工艺重用方法,实现基于三维CAD模型检索的快速NC编程。将三维CAD模型检索驱动的快速NC编程方法在原型系统中对数百个零件进行验证和应用。试验结果表明,该方法能够有效地实现对已有零件NC工艺设计成果的有效重用,可以提高NC加工工艺编制效率,满足企业的实际应用需求。     

基于领域本体的复杂产品设计知识检索技术

为解决产品数据管理系统中知识难以被发现和重用的问题,提出基于领域本体的设计知识检索技术.利用"领域本体-索引知识-数据资源"三层映射结构表达设计知识,形成以领域本体为语义模型和以索引知识为引导的设计知识体系.提出了基于语义的知识检索方法,对设计问题进行语义解析,转换成本体概念集,利用向量空间模型的相似度算法,在检索词元权重中引入语义关系权重,在索引知识词元权重中引入知识域权重,最终匹配符合设计人员检索意图的设计知识.以飞航导弹总体方案设计为例验证了知识检索技术的可行性.     

基于场论的本体中概念相似度求解方法

针对目前本体中概念相似度求解方法孤立考虑概念信息量或概念关系的问题,提出基于场论的概念相似度求解方法。该方法首先明确概念的语义关系是由概念包含的信息决定且隐性的概念关系通过显性的概念关系推出,并将概念包含的信息划分为共性信息与特性信息两类。结合场论的原理和方法,将本体映射为与物理场具有相同特性的语义场,将概念的共性信息和特性信息分别转化为语义引力元和语义距离,采用引力场模型计算概念的相似度。结合坦克装甲车辆和舰船领域知识检索需求,建立基于本体的语义检索系统,并通过与五种典型的相似度求解方法进行对比分析,验证了该方法的正确性和有效性。     

基于领域本体和CBR的案例知识检索方法

为解决汽车覆盖件模具设计经验依赖性强、隐形设计知识重用效率低、案例知识检索条件要求高、精确度低等问题,针对结构设计知识多源、异构、动态的特点及现有CBR方法的不足,建立了覆盖件模具设计知识的领域本体模型,构建了各本体概念之间的逻辑关系,并提出一种新的案例设计知识检索重用方法。该方法引入基于语义距离、节点深度和节点密度的数学模型,利用语义相似度计算和CBR原理结合(S-CBR)的方法,实现了设计案例知识的双层检索和快速重用,提高了检索效率和准确率,并开发了模具设计支撑系统。最后,以模具结构设计为例验证了所提方法的可行性和有效性。     

On the Relation of Load to Average Gap in the Contact Between Surfaces with Longitudinal Roughness

A computer simulation model for the contact between longitudinally-oriented rough surfaces has been formulated. This model closely duplicates the actual surf ace contact deformation behavior by taking into account the elastic interactions between the asperities. There were no assumptions made about the shapes, or any deformation behavior of the asperities, except for their obeying the laws of elasticity. The plastic deformations on the high asperity peaks were taken into account by setting a ceiling on their contact pressures at the material hardness value. The simulations used real surface profiles which were digitized from unworn circumferentially ground steel surfaces. Each pair of these profiles was mathematically combined to form an equivalent rough profile pressing against an infinitely rigid flat and having the appropriately adjusted elastic modulus. A total of 28 different pairs of profiles were used in the simulations. Each contacting pair was subjected to 30 different load levels and the local contact pressures and deformations were calculated. The contact simulations yielded some important mathematical relationships between parameters, such as the real area of contact, average gap, and average asperity load through statistical curve fitting. Two analytical functions were generated to relate the average load to average gap and the real area of contact to load.     

三绕组变压器的双绕组等效建模及在Matpower中的应用

针对实际电网存在着大量的三绕组变压器,但国际上一些著名商业软件,如BPA仿真软件、Matpower这一权威潮流计算开源软件,均只提供双绕组变压器模型,限制了其在具有三绕组变压器的电力系统中的应用的问题,潮流计算是自主开发的电力系统各种应用软件的核心模块,因此依托国际权威开源程序进行二次开发,是一种较好的选择。对Matpower要求的数据格式进行了归纳,对变压器的一般的等值电路及带理想变压器的等值电路和带标幺值的等值电路进行了分析研究,提出了三绕组变压器转换为双绕组等效模型的建模方法,使得原先只适应双绕组变压器的潮流计算软件可以适用于三绕组变压器电网的潮流计算;最后以Matpower软件为例进行了案例计算,并用PSASP仿真软件进行对比验证。研究结果证明,所提出的建模方法是有效的。     

电站锅炉模糊风险评价方法研究与应用

针对电站锅炉风险等级评价问题,将模糊综合评价技术应用到电站锅炉风险等级评价中。开展了电站锅炉失效影响因素及模糊评价因素的重要程度分析,建立了一套科学合理适于在线评价的电站锅炉风险评价体系,提出了模糊综合评价技术与改进的模糊层次分析法相结合的模糊风险评价方法,利用改进的模糊层次分析法计算了指标体系中各层指标权重。对某一台电站锅炉的实际运行工况影响子因素进行了模糊风险评价,采用模糊合成算子进行模糊综合运算得到电了站锅炉运行工况影响子因素的评价向量。研究结果表明:电站锅炉的运行工况影响子因素的风险评价等级为第6级,失效可能性等级为小,该电站锅炉运行工况良好。     

交通荷载作用下桥梁结构参数识别方法

应用动力节点加载法,将作用在桥梁上的交通荷载转化为等效节点荷载,再用两步构造法识别结构物理参数.第1步,用Newmark-β方法变换结构运动方程,并用结构的加速度响应求得变换空间内的位移、速度和加速度响应;第2步,基于最小二乘原理,构造出变换空间内求解结构参数的递推式,进行结构物理参数识别.数值模拟结果表明,在交通荷载作用下,该方法能够快速、准确地进行桥梁结构参数识别.     

Quantum Cooperative Robotics and Autonomy

The intersection of Quantum Technologies and Robotics Autonomy is explored in the present paper.The two areas are brought together in establishing an interdisci...     

考虑进油孔有限长滑动轴承油膜力的近似解析解

针对具有进油孔的有限长滑动轴承油膜力求解问题,采用变分原理和分离变量法,求得了有限长滑动轴承油膜压力分布的近似解析表达式。将油膜压力分布的近似解析表达式在油膜存在区域上进行积分,即得到了油膜力。将提出的计算有限长滑动轴承油膜力方法与无限长轴承模型、有限元方法的计算结果进行了比较,发现了提出的方法与有限元方法的计算结果很接近。最后,研究了进油孔位置和进油压力对油膜存在区域、油膜力等的影响,研究结果表明进油孔位置和进油压力对油膜存在区域和油膜力有较大的影响。     

RLS and LMS blind adaptive multi-user detection method and comparison in acoustic communication

RLS and LMS blind adaptive multi-user detection algorithm and multi-user detector was proposed to solve the problem of multi-user signal detection problem encountered in underwater acoustic communication networks.In simulation analysis,RLS and the LMS blind adaptive multi-user detector were designed and tested for synchronous and asynchronous multi-user communication process.The results of SIR comparison and MMSE comparison show that,both of the two methods can realize blind adaptive detection when any user change in multi-user communication,during this process,the training communication sequences are not needed.The RLS algorithm has about 5 dB higher in SIR compared with LMS algorithm,and the convergence velocity of RLS algorithm is also higher than LMS algorithm when the communication users change.RLS algorithm has better ability in multi-user detection than that of LMS algorithm,and it has great attraction and guiding significance for solving the problem of multiple access interference(MAI) in multi-user communication.     

Robust Impedance Control of Robots Using an Adaptive Interaction Force Observer

For robot interaction control,the interaction force between the robot and the manipulated object or environment should be monitored.Impedance control is a type ...     

Research on key techniques of expendable conductivity temperature depth measuring system

This paper analysis the developing of expendable conductivity temperature depth measuring system(XCTD)and introduce its principle of measuring about temperature,salinity and depth of ocean.Some key techniques are put forward.According to the real needs of XCTD,conductivity sensor with high sensitivity is designed by principle of electromagnetic induce,the ocean conductivity from induced electromotive force has been calculated.Adding temperature correction circuit would help to reduce error of conductivity measurement because of sharply changing temperature.Advanced temperature measuring circuit of high precision and the constant current source is used to weaken effect of self-heating of resistance and fluctuation of the source.On respect of remote data transmission,LVDS is a good choice for the purpose of guarantee the quality of data transmitted and the transmission distance is reaching to thousand meters in the seawater.Modular programming method is also brought into this research aimed at improve the stability,reliability and maintainability of the whole measuring system.In February,2015,the trials in South China Sea demonstrate that the developed XCTD realize effective measurement at a speed of 6 knots and detection depth at 800 m.The consistency coefficient of the acquired data is greater than 0.99 and the success rate of probe launching is above 90%.     

CHARACTERISTCS OF FLUID FILM IN OPTIMIZED SPIRAL GROOVE MECHANICAL SEAL

In order to investigate the sealing performance variation resulted from the thermal deformation of the end faces, the equations to calculate the fluid film pressure distribution, the bearing force and the leakage rate are derived, for the fluid film both in parallel gap and in wedgy gap. The geometrical parameters of the sealing members are optimized by means of heat transfer analysis and complex method. The analysis results indicate that the shallow spiral grooves can generate hydrodynamic pressure while the rotating ring rotates and the bearing force of the fluid film in spiral groove end faces is much larger than that in the flat end faces. The deformation increases the bearing force of the fluid film in flat end faces, but it decreases the hydrodynamic pressure of the fluid film in spiral groove end faces. The gap dimensions which determine the characteristics of the fluid film is obtained by coupling analysis of the frictional heat and the thermal deformation in consideration of the equilibrium condition of the bearing force and the closing force. For different gap dimensions, the relationship between the closing force and the leakage rate is also investigated, based on which the leakage rate can be controlled by adjusting the closing force.