为改善某整流器试样结构焊接工艺,对高温真空镍基合金钎焊过程展开了数值模拟研究,建立了高温钎焊真空炉中镍基合金钎料融化-润湿填充焊缝的流动模型。数值计算基于流体体积(volume of fluid,VOF)方法,综合考虑表面张力、重力、相变潜...为改善某整流器试样结构焊接工艺,对高温真空镍基合金钎焊过程展开了数值模拟研究,建立了高温钎焊真空炉中镍基合金钎料融化-润湿填充焊缝的流动模型。数值计算基于流体体积(volume of fluid,VOF)方法,综合考虑表面张力、重力、相变潜热等因素,采用层流模型求解得到了钎料随时间变化的流动行为。得到了固、液态钎料体积分布和温度场分布。虽然母材表面出现少部分钎料流失行为,并且在局部观察到有焊瘤的形成,但焊缝内钎料的整体填充效果良好,验证了钎焊工艺的钎料布置和温度控制的合理性。给出了关于时间和温度的钎料填充焊缝体积比的经验公式,为实际钎焊过程提供参考。展开更多
With the rapid development in the service,medical,logistics and other industries,and the increasing demand for unmanned mobile devices,mobile robots with the ability of independent mapping,localization and navigation ...With the rapid development in the service,medical,logistics and other industries,and the increasing demand for unmanned mobile devices,mobile robots with the ability of independent mapping,localization and navigation capabilities have become one of the research hotspots.An accurate map construction is a prerequisite for a mobile robot to achieve autonomous localization and navigation.However,the problems of blurring and missing the borders of obstacles and map boundaries are often faced in the Gmapping algorithm when constructing maps in complex indoor environments.In this pursuit,the present work proposes the development of an improved Gmapping algorithm based on the sparse pose adjustment(SPA)optimizations.The improved Gmapping algorithm is then applied to construct the map of a mobile robot based on single-line Lidar.Experiments show that the improved algorithm could build a more accurate and complete map,reduce the number of particles required for Gmapping,and lower the hardware requirements of the platform,thereby saving and minimizing the computing resources.展开更多
文摘为改善某整流器试样结构焊接工艺,对高温真空镍基合金钎焊过程展开了数值模拟研究,建立了高温钎焊真空炉中镍基合金钎料融化-润湿填充焊缝的流动模型。数值计算基于流体体积(volume of fluid,VOF)方法,综合考虑表面张力、重力、相变潜热等因素,采用层流模型求解得到了钎料随时间变化的流动行为。得到了固、液态钎料体积分布和温度场分布。虽然母材表面出现少部分钎料流失行为,并且在局部观察到有焊瘤的形成,但焊缝内钎料的整体填充效果良好,验证了钎焊工艺的钎料布置和温度控制的合理性。给出了关于时间和温度的钎料填充焊缝体积比的经验公式,为实际钎焊过程提供参考。
基金National Key Research and Development of China(No.2019YFB1600700)Sichuan Science and Technology Planning Project(No.2021YFSY0003)。
文摘With the rapid development in the service,medical,logistics and other industries,and the increasing demand for unmanned mobile devices,mobile robots with the ability of independent mapping,localization and navigation capabilities have become one of the research hotspots.An accurate map construction is a prerequisite for a mobile robot to achieve autonomous localization and navigation.However,the problems of blurring and missing the borders of obstacles and map boundaries are often faced in the Gmapping algorithm when constructing maps in complex indoor environments.In this pursuit,the present work proposes the development of an improved Gmapping algorithm based on the sparse pose adjustment(SPA)optimizations.The improved Gmapping algorithm is then applied to construct the map of a mobile robot based on single-line Lidar.Experiments show that the improved algorithm could build a more accurate and complete map,reduce the number of particles required for Gmapping,and lower the hardware requirements of the platform,thereby saving and minimizing the computing resources.
