共查询到19条相似文献,搜索用时 203 毫秒
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针对我国特殊钢的钢坯局部修磨问题,开发出一种三自由度虚拟轴机床。建立静力学和动力学方程,并对静力学和动力学特性进行研究。由于机床的外力和外力矩分别由驱动杆和平行机构承受,其力学模型和位置控制都变得简单易行。通过结构柔度系数矩阵对机床刚度特性进行考察,表明在工作空间的横截面内,越接近中心,机床刚度越高。动力学方程的仿真表明各杆驱动力有相似性,且运动平台的质量对各杆驱动力的影响较大。 相似文献
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从机器人学的角度来看,并联机构的静力学和运动学之间存在一定的联系,对于少自由度并联机构,其运动学和静力学之间的关系比较复杂,特别是静刚度计算问题更为复杂。使用矢量法推导了五自由度并联机床速度Jacobian矩阵和力Jacobian矩阵之间的关系,并应用此关系解决了并联机床的静力学问题。在并联机床静力学和运动学研究的基础上,提出了一种新的静刚度计算方法,并对并联机床在一些位姿下的静刚度进行了计算。计算结果表明,该方法可行,为并联机床的设计、机构学特性的研究提供了具有使用价值的指导。 相似文献
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基于MATLAB的三自由度并联机床的静力特性分析 总被引:1,自引:0,他引:1
文章介绍了一种三自由度并联机床的机构特点.在对该并联机构静力分析的基础上,利用虚功原理建立了并联机床的静力平衡方程.在MA丁LA日环境下对并联机床的整体受力进行了研究,获得了其应力及应变的分布变化规律.研究结果表明:在其工作空间内,各驱动单元的驱动力变化趋势平稳,没有突变,具有良好的力学特性.为并联机床的机构优化和动力学研究提供了理论基石出. 相似文献
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Wei-Yao Hsu Jenq-Shyong Chen 《The International Journal of Advanced Manufacturing Technology》2004,24(11-12):899-909
This paper focuses on the error analysis and calibration methodologies for a parallel kinematic machine (PKM) called a Cartesian-guided tripod (CGT). The CGT volumetric error due to the geometric error, kinematic parameter error and nonlinear machine stiffness were studied. It is well known that the PKM nonlinear machine stiffness can produce significant volumetric errors from several tens to several hundreds of micrometres depending on the averaged value and deviation range for the machine stiffness. For most PKMs, joint level sensors are used to estimate the virtual Cartesian movements of the cutting tool. The nonlinear stiffness effect is not detected by this indirect metrology method and must be compensated for by a calibration methodology. A solution for the nonlinear stiffness effect implemented on the CGT involves using a passive Cartesian guiding/metrology leg that is independent of the driving legs to directly measure the Cartesian movement of the motion platform. Because the metrology loop of the Cartesian guiding/metrology leg is separated from the kinematic loops of the driving legs, the volumetric accuracy of the CGT is immunised against thermal errors and load deformations on the drive mechanisms. The passive Cartesian guiding/metrology leg is also used for the auto-calibration of the CGT kinematic parameters. The auto-calibration methodology and simulation results were studied and reported. 相似文献
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基于正交试验的机床结合部动刚度优化配置 总被引:1,自引:0,他引:1
机床中结合部分布众多且不同接触条件下其动刚度值不同,优化分析时很难研究每个动刚度值对机床动态性能的影响。针对此类问题,提出一种基于正交试验的机床结合部动刚度优化配置方法。该方法通过模态柔度与弹性能分布理论判定机床的薄弱模态和薄弱结合部,建立以薄弱结合部的动刚度为设计变量,各阶薄弱模态的最小模态柔度为目标的多目标优化模型。为提高优化效率,采用正交试验方法规划试验方案,并在试验结果分析中引入相似优先比法对结合部动刚度进行协同优化配置。以某型立式加工中心为例,采用优化配置方法确定其结合部动刚度的最优配置方案。仿真结果显示该方案下薄弱模态的模态柔度明显降低,整机动态性能提高,验证了该方法的可行性。 相似文献
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Nicole Zirkelback 《摩擦学汇刊》2013,56(2):337-343
A finite element analysis for the isothermal flow in spiral groove gas face seals is detailed along with a successive approximation method for the iterative solution of the nonlinear Reynolds equation. Zeroth- and first-order pressure fields are calculated for evaluation of the seal opening force and leakage and the axial stiffness and damping force coefficients, respectively. A parametric study shows the static and dynamic force behavior of a baseline SGFS operating with a large pressure ratio. The recommended geometric parameters presented ensure large static stiffness and damping force coefficients while still allowing for low seal leakage rates. A reduction in the power loss and a significant increase in the seal static stiffness coefficient are unique features of thin seal dams. 相似文献
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混联机床的静刚度实验测量 总被引:1,自引:0,他引:1
机床的静刚度是保证其工作性能的重要指标,用理论模型对机床静刚度进行研究难免产生偏差,因此有必要对其进行实验研究.文中针对一台近期研发成功的混联机床,利用力传感器和千分表对其进行静刚度的实验研究.对实验数据进行最小二乘直线拟合,得到该机床在工作空间内9个位姿的各方向静刚度.为了研究该机床静刚度的变化情况,计算同一水平面或竖直面内的静刚度变化率.文中方法和结论为该类型机床的静刚度理论研究和仿真提供实验依据. 相似文献
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Jun Wu Jinsong Wang Tiemin Li Liping Wang 《The International Journal of Advanced Manufacturing Technology》2007,34(3-4):413-420
This paper focuses on the dynamic characteristics of the two degree-of-freedom (DOF) planar parallel manipulator of a heavy
duty hybrid machine tool. The Newton-Euler approach is employed to derive the inverse dynamic equation of the parallel manipulator.
According to the motion planning of the cutting tool, dynamic simulation without cutting force is performed, and the ratio
of the masses of counterweights to that of moving parts (not including the counterweight) is optimized. It demonstrates that
the manipulator which is designed with over constraint can improve the dynamic behaviour. Furthermore, the cutting force model
for face milling is introduced and the dynamic simulation with the dynamic cutting force is carried out. Simulation shows
that the oscillation of cutting force is one cause of the vibration of the machine tool in the milling process. In the detailed
design, some modification in the structure of the machine tool is made to suppress the vibration. 相似文献
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横梁是龙门机床的主要承力部件,其结构和静、动态力学特性直接影响机床的加工精度。为分析其结构设计是否满足机床的精度要求,以及筋板结构和布局形式对其静态特性的影响,文中应用有限元分析方法,针对某型定梁龙门机床横梁进行静力学特性分析,计算了其最大静变形和最大静应力,分析了结构设计上的薄弱环节,然后对其内部筋板的结构和布局形式进行了优化设计和分析对比。结果表明,优化后横梁的静刚度提高了12.89%,最大静应力降低了18.01%,显著改善了横梁的静力学特性。 相似文献
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提出一种机床整机动态分析指导薄弱部件改进的优化思路,即通过对机床整机的动刚度进行分析,辨识出不同激振频率下整机中的薄弱环节,明确优化目标,提高优化效率。利用ANSYS Workbench软件对一种卧式加工中心进行谐响应分析和模态分析,辨识出立柱是整机x向和z向动刚度的最薄弱环节。以立柱结构为优化对象,运用灵敏度分析法计算出立柱质量和固有频率对各个壁板的灵敏度。以立柱固有频率为优化目标,立柱质量为约束条件,建立优化方程。利用Matlab软件求解该方程,得到立柱的优化结果。通过谐响应分析得到优化后机床整机的动刚度,结果表明,优化后立柱在质量不增加的情况下,整机在x向和z向的最大共振峰值降低约6.5%,相应的共振频率提高约10%。 相似文献
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为了研究油膜厚度对静压支承的影响,以闭式液体静压导轨为研究对象,确定了导轨系统的初始参数;基于力平衡方程及流量方程,建立了功率损失、静态性能、动态性能的数学模型;将总功率损失、承载能力和静刚度、固有频率、调整时间和动刚度等参数作为导轨的性能指标,利用MATLAB软件定量分析了油膜厚度对导轨性能的影响。研究结果表明:增大油膜厚度,则液体静压导轨的总功率损失增大,调整时间变长,承载能力不变,静刚度、固有频率及动刚度减小。因此,减小油膜厚度,可降低导轨总功率损失,提高静态性能和动态性能。研究结果为工程实际中闭式液体静压导轨静压油膜的设计提供了理论依据。 相似文献