机器人点焊工作站在汽车制造中的应用

机器人焊接系统属于多智能体系统（Multi—Agent systems,MAS）,机器人点焊系统集成的关键是如何处理好MAS的通信和工作协调。本文介绍汽车车身机器人点焊的工作流程,重点介绍了机器人点焊工作站的控制原理及工作站集成技术。     

丹麦开发出新型生物质燃料供热锅炉

壳牌公司在丹麦Herning自治市的协助下新建了一台以生物质为燃料的供热锅炉。这台完全自动化的锅炉机组已在Herning Ikast工业区投运,为当地的工业用户供热。锅炉采用组合式结构,供热功率可达10 kW ~300 kW,并配有燃料储备仓和所有的必备连接端,在需要安装额外机组时能够保证迅速装配。这种机组取代了传统的以化石为燃料的锅炉,特别适用于小规模工业用户、政府机关和学校。不过用户还得同以往使用常规燃料能源那样按月交费以购买这种生物质燃料能源。锅炉所用生物木材来自于可持续生长森林。此类机组所用燃料为直径8 mm~10 mm的木球…     

矿物掺和料和再生骨料对混凝土的收缩性能的影响

研究了再生粗、细骨料取代量、矿物掺和料等因素对再生混凝土收缩性能的影响.结果表明:高品质再生细骨料混凝土的后期收缩值高于天然骨料混凝土,且随着再生细骨料取代量的增加而增大;高品质再生粗骨料混凝土的收缩值接近天然骨料混凝土;粉煤灰和普通矿粉相比能够很好的降低再生混凝土的早期和后期收缩值,超细矿粉和硅灰都能减少再生混凝土的后期收缩值,但硅灰增加了再生混凝土的早期收缩值.     

Experimental investigation and numerical analysis of unsteady attached sheet- cavitating flows in a centrifugal pump

This paper studies the attached sheet cavitation in centrifugal pumps. A pump casted from Perspex is used as the test subject. The cavitation bubbles were observed in the entrance of the impeller and the drops of the head coefficients were measured under different operating conditions. A Filter-Based Model (FBM), derived from the RNG k – ? model, and a modified Zwart model are adopted in the numerical predictions of the unsteady cavitating flows in the pump. The simulations are carried out and the results are compared with experimental results for 3 different flow coefficients, from 0.077 to 0.114. Under four operating conditions, qualitative comparisons are made between experimental and numerical cavitation patterns, as visualized by a high-speed camera and described as isosurfaces of the vapour volume fraction α_v = 0.1. It is shown that the simulation can truly represent the development of the attached sheet cavitation in the impeller. At the same time, the curves for the drops of the head coefficients obtained from experiments and calculations are also quantitatively compared, which shows that the decline of the head coefficients at every flow coefficient is correctly captured, and the prediction accuracy is high. In addition, the detailed analysis is made on the vapour volume fraction contours on the plane of span is 0.5 and the loading distributions around the blade section at the midspan. It is shown that the FBM model and the modified Zwart model are effective for the numerical simulation of the cavitating flow in centrifugal pumps. The analysis results can also be used as the basis for the further research of the attached sheet cavitation and the improvement of centrifugal pumps.     

一种动态特征匹配的部分重叠点云配准方法

点云配准方法能够有效地完成对不同重叠率、不同规模点云间的配准,可确保三维重建模型的精度。针对该问题,提出一种动态特征匹配的部分重叠点云配准方法,首先基于欧氏距离分割法将点云分割为子点云;然后提取子点云特征,考虑到不同点云的规模不同,提取的特征规模也是不同的,提出利用动态时间规整算法(DTW)完成子点云间的映射;最后利用迭代配准算法求取拼接点云间的平移、旋转矩阵,利用该矩阵完成点云间的配准和拼接。实验结果表明,提出的方法能够有效地解决部分重叠点云和不同规模点云的配准问题。     

宽缝混凝土板护坡在北大港水库水毁护坡修复中的应用

简单介绍了北大港水库混凝土板护坡修复工程,对水毁护坡的破损机理作了简要的分析,希望能够通过该工程实例为水库水毁护坡的修复提供参考。     

PKI技术在基于B/S的MRP系统中的应用

本文主要讨论PKI在基于B/S架构MRP系统中的应用,试图为企业信息化安全建设提供一些有益的思路。     

富/乏油下滚子修形对圆柱滚子轴承剪切应力的影响

以NJ2205圆柱滚子轴承为分析对象,通过Ansys软件对滚子进行建模,分析富油和乏油工况下滚子与滚道之间出现的"边缘效应"问题,对比分析未修形、全凸修形和对数修形下滚子与滚道剪切应力分布情况.结果表明,在径向载荷为11.45 kN、转速为4000 r/min、富油工况下,沿滚子母线方向的剪切应力小于乏油,无修形方式时剪切应力最大,对数修形方式时剪切应力最小;在富油工况和乏油工况下,全凸修形时的剪切应力相比于未修形时分别减小了17.02％和10.58％;对数修形时的剪切应力相比于未修形时分别减小了32.95％和17％.因此,NJ2205圆柱滚子轴承的滚子采用对数修形曲线能有效地降低剪切应力.     

再生骨料和矿物掺合料对再生混凝土强度的影响

研究了再生骨料取代量和矿物掺合料等因素对再生混凝土强度的影响。结果表明:高品质再生细骨料混凝土的强度高于天然骨料混凝土,且随着再生细骨料取代量的增加而增大;高品质再生粗骨料混凝土的强度接近天然骨料混凝土强度。再生骨料和各种掺合料的适应性比较好,超细矿粉和普通矿粉复掺能够明显提高再生混凝土强度。