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对开放式数控系统和并行数控系统进行了研究,提出了一种由PC机和ARM+DSP双核微处理器构成的开放式并行数控系统,给出了该系统的硬件构建方式及各部件之间的通信方法.在对该数控系统的主要计算任务进行分析的基础上,对数控系统中的计算任务进行了分配,提出了使这些任务并行的方法,使这些计算任务能在PC机和微处理器上并行运行.使用该方法能够快速构建开放的数控系统,并能充分利用闲置的计算资源,提高数控系统的功能和加工效率. 相似文献
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介绍了运用投影原理,在三维CAD中作出零件的三维造型,并依此生成二维工程图,在二维工程图中进行标注,从而得到准确的成形车刀截形尺寸数据的方法。该方法兼具作图法直观与计算法准确的优点,为工程设计与计算提供了一种新的思路。 相似文献
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在板料的中性层上,综合运用平行、放射线投影法对复杂覆盖件右支撑梁形状展开进行研究.以UG软件为展开计算平台,通过两种投影法展开该覆盖件,光滑连接投影展开线的端点,得到该件展开外形的轮廓.根据覆盖件和展开件面积相等的原则,验证了该展开形状的精确. 相似文献
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赤平极射投影在预测地下矿山采场顶板冒落规模的应用 总被引:2,自引:0,他引:2
介绍了赤平极射投影的基本原理,着重讨论了利用赤平极射投影法预测地下矿山采场顶板冒落规模的方法,最后结合矿山实例对本方法加以验证,说明该方法应用于地下矿山采场顶板冒落规模预测是可行的。预测结果与实际情况基本相符。 相似文献
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基于模拟退火法的公差并行优化设计 总被引:1,自引:0,他引:1
在考虑装配功能要求、加工方法选择、加工余量公差、经济加工精度范围等约束因素的基础上,建立公差并行设计的数学模型,并应用模拟退火法计算。 相似文献
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模具并行开发活动规划理论和方法研究 总被引:2,自引:1,他引:2
给出了并行活动描述方法和规划模型,将一种新的活动规划算法引入模具并行开发活动调度,充分考虑并行活动执行时间的不确定性,在保证设计信息、活动时序许可的前提下有效利用设计资源,以达到最大限度地提高模具开发的并行度、缩短开发周期的目的。具体算例表明了该算法的有效性、可行性。 相似文献
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针对目前在板料成形反向模拟法中常用到的初始域计算方法的缺点,提出采用一种基于弹簧系统能量理论的空间网格映射法。该算法克服了垂直投影法因零投映面积而不能迭代计算的问题,解决了几何映射法需要寻找对称线、断面线展开法无法解决局部网格畸变的问题。NUMISHEET 2002一标准考题中,通过与增量模拟软件eta/DYNAFORM的比较,证明了采用基于弹簧系统能量理论的调和映射思想来求解反向模拟法初始域具有较好的适用性,同时验证了反向模拟法较为可靠的计算结果及较高的计算效率。 相似文献
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提出一种新的基于投影法的隐式有限差分算法,用于计算速度场和压力。这种方法的特点是将计算区域根据雷诺数分成几个区域;对于远离壁面的区域,热金属流按牛顿流计算;对于贴近壁面的区域,热金属流按非牛顿流计算。通过非参数统计和实验的方法证明新算法的正确性。数值模拟结果表明,新算法的计算速度要快于基于SOLA-VOF法的显式有限差分方法。 相似文献
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In computed tomography, targeted (or zoomed) reconstruction is usually used to achieve high-resolution reconstruction to a small region-of-interest (ROI). This paper reports a novel targeted reconstruction method based on the recently developed differential planar computed tomography technology. With the central-slice sinogram of scanning a planar object, the primary orientation of the object is first determined for the first projection. Then by identifying the dimensions of the ROI and its offsets to the centre-of-rotation (COR), the targeted reconstruction matrix is defined, which just covers the ROI and follows its initial orientation at the scan start time. By scanning and reconstructing a small planar ROI soldered on a large planar substrate, we demonstrate the advantages of the proposed method over traditional CT, including the smaller reconstruction size and less computation time, high-resolution reconstruction and good-orientated CT image for subsequent de-layering and visualization. 相似文献
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Rake angle and its distribution on the cutting edge of a twist drill are of vital importance to its performance. This paper presents a practical method to determine the cutting edge and rake angles. Firstly, 3D coordinates of the points on the cutting edge are inspected by using 2D measurement apparatus. Secondly, the flute profile is deduced from the data measured, and the rake angles are evaluated by numerical computation. Conventionally, rake angle calculation is based on a series of plane definitions and laborious work in plane projection is inevitable. To facilitate the process, a vector based procedure is presented. As an example, cutting edge of a standard drill is measured by using tool microscope and image-based instrument. In each case, the normal rake angle distribution is determined. Numerical results exhibit that average error and mean square error of the latter deviated from the former are 0.95o and 0.33o, respectively. It verifies the validity of the proposed procedure and the measurement device. 相似文献
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ABSTRACTThis paper introduces a novel facile method, called projection friction stir spot welding, to produce a keyhole-free friction stir welds based on a pinless tool method involving using a specially designed projection on the surface of the backing anvil. The projection plays two key roles contributing to the bonding mechanism and the joint strength: (i) encouraging the material flow perpendicular to the joint interface and (ii) bending the joint interface at the edge of the projection. The process enables pathway to produce keyhole-free welds with superior mechanical performance in steel sheets compared to the other spot welding techniques. 相似文献
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为提高扇束滤波反投影(FBP)算法重建CT图像的速度,提出了利用正余弦函数性质对极坐标反投影算法进行优化的快速重建方法。首先将扇束等距CT扫描得到的投影数据进行加权,卷积滤波处理;其次将预处理后的投影数据运用正余弦函数性质进行极坐标反投影重建。试验结果表明,与传统的卷积反投影重建算法相比,该方法可以将重建速度提高4倍以上,而且重建质量与传统卷积反投影相当。这种算法也适应于多层螺旋三维重建,并且可以推广到三维锥束重建。 相似文献