首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   38篇
  国内免费   3篇
  机械仪表   41篇
  2018年   2篇
  2017年   2篇
  2016年   4篇
  2015年   1篇
  2014年   2篇
  2013年   2篇
  2012年   6篇
  2011年   1篇
  2010年   4篇
  2009年   2篇
  2008年   4篇
  2006年   1篇
  2003年   2篇
  2002年   2篇
  2001年   4篇
  2000年   1篇
  1997年   1篇
排序方式: 共有41条查询结果,搜索用时 31 毫秒
1.
自由曲面五轴加工刀轴矢量的运动学优化方法   总被引:4,自引:4,他引:1  
针对五轴加工中刀轴矢量变化过大导致加工误差较大和破坏零件表面加工质量的问题,提出采用运动学方法优化刀轴矢量.建立机床的运动学约束条件,并由此确定机床转动角速度可达区域作为刀轴矢量优化的约束条件.针对选定结构的机床,结合平底刀加工不发生过切的充要条件和被加工曲面沿行距方向的法曲率,给出初始后跟角的自动计算方法,并指出机床转动角度的变化相对于后跟角的变化是单调的.在得出切触点无干涉区域与机床转动角速度可达区域的基础上,从两个区域的交集中选取优化的刀轴矢量.如果两个区域的交集为空,则调整该点之前切触点的刀轴,从而使交集不为空.算例分析表明,所提出的运动学优化方法合理可行,能够使刀轴矢量变化均匀,充分发挥机床的性能.  相似文献
2.
This paper describes a novel methodology for the reverse engineering of complex, free form surfaces, based on the integration of the measurement information from a 3D vision sensor and a coordinate measuring machine (CMM). The aim is to reconstruct the CAD model of objects of complex geometry with high accuracy and at the same time, rapidly exploiting the advantages deriving from the use of both the optical and the mechanical sensors, with a minimum of human intervention. The combination is performed at the level of measurement information, within a module for the intelligent aggregation of the information from optical and mechanical sensors. Tools are developed for digitising, filtering, grouping and surface-fitting the 3D images of the vision sensor and the point clouds from digitisation of the CMM. In the paper, the combined system is described, and two industrial applications are presented.  相似文献
3.
Point Data Reduction Using 3D Grids   总被引:3,自引:3,他引:13  
Reverse engineering refers to the process of obtaining a CAD model from an existing physical part. Advances in laser scanning technologies have facilitated this process by sampling part surface data with speed and accuracy. With the help of this technology, it is now possible to acquire the geometry of a part having complex and freeform surfaces. However, it creates the burden of large amounts of point data which must be manipulated, therefore, data from a laser scan must be significantly reduced to proceed with the computations and to lower the storage requirement. Many point data reduction methods for image processing have been developed in the past. However, there is little published work on laser-scanned data, and what exists focuses only on 2D point data. This paper presents a data reduction method that reduces the amount of 3D point data using part geometry information. The method reduces the point data, based on normal values of points using 3D grids. The method is applied to two sample models and the results are discussed.  相似文献
4.
Error Compensation for Three-Dimensional Line Laser Scanning Data   总被引:3,自引:3,他引:1  
In this paper, the problem of compensation of 3D line laser scanning data for improved inspection accuracy is addressed. This problem is important, as a 3D line laser scanner is about one order less accurate than a touch probe. The approach taken is to compensate through error characterisation. In other words, a software compensation is performed, instead of a hardware compensation, which is probably more expensive. To do so, the errors associated with a 3D line laser scanning system are first characterised. With error characterisation, an empirical formula is obtained relating the errors to the influencing factors including the projected angle and the scan depth. This empirical formula is used to compensate for the digitised surface data obtained by the corresponding laser scanning system. The results show that the proposed approach effectively improves inspection accuracy.  相似文献
5.
A laser sensor with multiple detectors for freeform surface digitization   总被引:3,自引:3,他引:0  
In this paper, an integrated laser scanning sensor for freeform surface digitization is presented. The sensor consists of a diode laser light source and four position-sensitive device (PSD) detectors. The stand-off distance of the sensor is 180 mm and the measurable range is 90 mm. The Lambert model is applied to calculate the displacement between the sensor and the measured point on the object surface along the optical axis, under the assumption of a diffusive surface. The inclination angle of the measured point from the vertical plane of the laser beam is calculated by mathematical inference. Those data are used in error compensation to improve the system precision. The new design of multiple detectors could increase the measurable angle and could solve the dead-space problem in the single-point laser of triangulation measurement. The computer simulation and actual measurements show that the displacement resolution is around 50 μm, and the system performs well in terms of stability and repeatability. The sensor system could be mounted on the NC machine or on the XY platform for freeform surface digitization.  相似文献
6.
一种利用自由曲面透镜的LED路灯配光设计与研究   总被引:2,自引:2,他引:0  
罗元  毛建伟 《光学仪器》2012,34(2):72-75
随着半导体照明技术的发展,LED路灯应用日益广泛。其二次配光设计对LED路灯照明具有重要的作用。LED路灯应用中,为了使其照度和照度均匀度满足一定的要求,设计采用了自由曲面透镜的二次配光。根据折射定律、目标照明面光分布和照度均匀建立自由曲面的方程,数值法求得面型数据并导入建模软件拟合成透镜实体,对利用自由曲面透镜配光的LED及LED路灯进行了光线追迹仿真及分析。结果表明基于自由曲面透镜的LED路灯具有较好的照度、亮度和均匀度。  相似文献
7.
微型投影机自由曲面LED聚光器的设计   总被引:1,自引:1,他引:1  
为提高LED微型投影机中光学引擎的效率和结构紧凑性,研究了自由曲面LED聚光器结构和工作原理,设计了含有折射和反射自由曲面的LED聚光器。采用非成像理论和同时多表面设计方法,计算并获得了聚光器折射和反射两个自由曲面在子午截面内的各点坐标,利用聚光器的旋转对称性得到了其在三维空间内的面形数据。设计结果的光学建模仿真分析表明:所得聚光器能够有效地收集大功率LED光源的能量,并将光束发散角控制在12°内,其光能收集率达到71%。与采用反射式聚光器的设计方案相比,光能收集率提高了20%,而体积则下降了70%,有效地提高了光学引擎的效率和紧凑性。本项设计对LED微型投影仪的小型化具有指导和借鉴作用。  相似文献
8.
A new milling methodology with the equivalent normal curvature milling model machining freeform surfaces is proposed based on the normal curvature theorems on differential geometry. Moreover, a specialized whirlwind milling tool and a 5-axis CNC horizontal milling machine are introduced. This new milling model can efficiently enlarge the material removal volume at the tip of the whirlwind milling tool and improve the producing capacity. The machining strategy of this model is to regulate the orientation of the whirlwind milling tool relatively to the principal directions of the workpiece surface at the point of contact, so as to create a full match with collision avoidance between the workpiece surface and the symmetric rotational surface of the milling tool. The practical results show that this new milling model is an effective method in machining complex three- dimensional surfaces. This model has a good improvement on finishing machining time and scallop height in machining the freeform surfaces over other milling processes. Some actual examples for manufacturing the freeform surfaces with this new model are given.  相似文献
9.
基于虚拟环境的集成快速模具制造系统研究   总被引:1,自引:1,他引:6  
提出基于虚拟环境的集成快速模具的制造系统方法,着重探讨自由曲面重构、特征建模、模具制造并行机制与虚拟环境、快速模具制造等关键技术,并提出系统实现的技术路线。  相似文献
10.
江剑宇  杨波 《光学仪器》2018,40(1):55-60
为了满足三维测量系统所需的大视场照明条件,设计了一种基于自由曲面的透镜阵列的匀光照明模块。根据能量对应关系计算得到自由曲面透镜的离散点数据,通过Rhino软件拟合离散点得到该自由曲面透镜实体模型,再将得到的自由曲面透镜面型导入Light Tools软件,进行阵列后得到匀光照明模块。仿真结果表明,该照明模块可使2.56 m2的接收面上的亮度达到13 102 lx,照明均匀度达到92.86%,且公差符合装配要求。  相似文献
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号