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1.
Aspheric optics has been widely employed in some high-tech industries for its superiority. In order to achieve the ultra-precision machining of these aspheric surfaces, the large optical ultra-precision grinding machine becomes crucial because it determines the efficiency of the whole process. As the key functional unit in ultra-precision machine tool, the hydrostatic guideways are commonly adopted for the excellent performance. However, the motion errors of hydrostatic guideways have a direct influence on the accuracy of the machined workpiece, and some analysis approaches have been reported correspondingly. Although the existed analysis models do work, their imperfections also can be easily captured. Accordingly, a novel analysis model with less imperfection is deserved to be developed. In this paper, the kinematic theory is utilized to establish the quasi-static analysis model for motion errors in closed hydrostatic guideways. Through the large ultra-precision grinding machine designed by our research group, the consistently good agreement between the predicted results and the measured experimental data are obtained. Furthermore, it is found that the motion accuracy is more sensitive to the profile error of the guide rail bearing the external load rather than that of the other guide rail in the closed hydrostatic guideway. The presented research is supposed to be valuable to the peer designers. 相似文献
2.
针对新型机器人多自由度运动机构的需求,提出了一种新型六相双定子螺旋运动永磁执行器。执行器特点在于每个定子均为六相双Y移30°绕组,两个定子铁心采用螺旋形齿槽结构,对两个定子绕组通入六相不同相序电流组合便可产生多自由度运动方式。执行器具有控制方式灵活、容错性能强、可靠性稳定等优点。首先对螺旋运动永磁执行器的结构及运行机理进行分析,推导了执行器的磁链方程、电压方程、转矩和推力方程。最后构建了瞬态三维多自由度数值分析模型,得到了磁链、电压、转矩和推力的波形,验证了运行机理的正确性。 相似文献
3.
针对光照变化和大位移运动等复杂场景下图像序列变分光流计算的边缘模糊与过度分割问题,文中提出基于运动优化语义分割的变分光流计算方法.首先,根据图像局部区域的去均值归一化匹配模型,构建变分光流计算能量泛函.然后,利用去均值归一化互相关光流估计结果,获取图像运动边界信息,优化语义分割,设计运动约束语义分割的变分光流计算模型.最后,融合图像不同标签区域光流,获得光流计算结果.在Middlebury、UCF101数据库上的实验表明,文中方法的光流估计精度与鲁棒性较高,尤其对光照变化、弱纹理和大位移运动等复杂场景的边缘保护效果较优. 相似文献
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针对狭窄工作空间,微创手术机器人受限于机械手末端执行器灵活度不足,导致医生无法有效进行手术操作的问题。本论文提出一种新型变曲率柔性关节微创手术机械手,通过刚柔体同轴嵌联结构,控制外层柔性关节机加工弹簧和内层刚性基杆的耦合长度,实现机械手前端连续变曲率万向弯曲运动。论文阐述了机械手柔性关节设计、动力传递实现方法及使用ANSYS软件完成重要部件仿真分析;构建运动控制模型,并利用MATLAB软件得到末端执行器的工作空间;实验验证微创手术机械手柔性关节变曲率弯曲运动。结果表明狭窄空间下,微创手术机械手实现了连续、有规律的变曲率万向弯曲运动。 相似文献
6.
It is known that optical flow estimation techniques suffer from the issues of ill-defined edges and boundaries of the moving objects. Traditional variational methods for optical flow estimation are not robust to handle these issues since the local filters in these methods do not hold the robustness near the edges. In this paper, we propose a non-local total variation NLTV- optical flow estimation method based on robust weighted guided filtering. Specifically, first, the robust weighted guided filtering objective function is proposed to preserve motion edges. The proposed objective function is based on the linear model which is computationally efficient and edge-preserving in complex natural scenarios. Second, the proposed weighted guided filtering objective function is incorporated into the non-local total variation NLTV- energy function. Finally, the novel NLTV- optical flow method is performed using the coarse-to-fine process. Additionally, we modify some state-of-the-art variational optical flow estimation methods by the robust weighted guided filtering objective function to verify the performance on Middlebury, MPI-Sintel, and Foggy Zurich sequences. Experimental results show that the proposed method can preserve edges and improve the accuracy of optical flow estimation compared with several state-of-the-art methods. 相似文献
7.
叶婉玲 《电信工程技术与标准化》2019,32(8)
从MR原始数据特性出发研究数据结构与字段,采用基于线状特性分析MR大数据的地铁用户识别过滤方法和位置定位方法,该方法经过验证能够有效输出地铁用户数据并定位在地图上,解决人工地铁测试效率低且测试片面的问题,实现基于大数据的自动化地铁网络评估,提供海量的有效定位数据用于地铁评估与分析。 相似文献
8.
以串联机器人为研究对象,设计了一种三自由度串联运动平台,用于汽车驾驶模拟器。运用Inventor建立串联平台的三维模型,导入Adams,获得了平台的虚拟样机。针对汽车主要运行状态进行运动分解,设计虚拟样机的驱动函数模拟汽车运动时的动感,得到了各自由度运动及关键构件的状态参数。分析比较了平台有无减震装置时的性能,对各自由度传动方程进行了验证。提出一种基于Adams和Matlab联合仿真工作空间的新方法,并用该方法绘制了座椅质心的工作空间。获得的仿真数据为后续物理样机的结构设计、运动控制提供了可靠依据。 相似文献
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10.
Conservative Approximation–Based Full‐Search Block Matching Algorithm Architecture for QCIF Digital Video Employing Systolic Array Architecture 下载免费PDF全文
This paper presents a power‐efficient hardware realization for a motion estimation technique that is based on the full‐search block matching algorithm (FSBMA). The considered input is the quarter common intermediate format of digital video. The mean of absolute difference (MAD) is the distortion criteria employed for the block matching process. The conventional architecture considered for the hardware realization of FSBMA is that of the shift register–based 2‐D systolic array. For this architecture, a conservative approximation technique is adapted to eliminate unnecessary MAD computations involved in the block matching process. Upon introducing the technique to the conventional architecture, the power and complexity of its implantation is reduced, while the accuracy of the motion vector extracted from the block matching process is preserved. The proposed architecture is verified for its functional specifications. A performance evaluation of the proposed architecture is carried out using parameters such as power, area, operating frequency, and efficiency. 相似文献