共查询到20条相似文献,搜索用时 15 毫秒
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Wei Gao Makoto Tano Takeshi Araki Satoshi Kiyono Chun Hong Park 《Precision Engineering》2007,31(3):310-316
This paper describes the measurement and compensation of error motions of a diamond turning machine for nanofabrication of large sinusoidal metrology grids. The diamond turning machine has a T-base design, which consists of a spindle with its rotation axis along the Z-direction and a cross-slide with its movement direction along the X-direction. A fast-tool-servo (FTS) unit is mounted on the X-slide to generate sinusoidal microstructures on a flat workpiece surface mounted on the spindle. The error motions of the X-slide and the spindle, which introduce Z-directional profile errors (out-of-flatness) on the grid surface, are measured and compensated. The out-of-straightness of the X-slide is measured to be approximately 60 nm over a travel of 80 mm by using the reversal method. It is also confirmed that the out-of-straightness of the X-slide has a 10-nm periodic component with a period of 11 mm corresponding to the diameter of the needles used in the roller bearing of the X-slide. The angular motion of the spindle is measured to be approximately 0.3″ by using an autocollimator, which can cause a 73-nm out-of-flatness over a workpiece 100 mm in diameter. The axial motion of the spindle is measured to be approximately 5 nm, which is the smallest error motion. The out-of-flatness of the workpiece is reduced from 0.27 to 0.12 μm through compensating for the error motions by utilizing the FTS unit based on the measurement results of error motions. 相似文献
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In single-point diamond turning (SPDT), two-dimensional (2D) tool centre error is caused by the tool deviating from the workpiece rotation centre both in the horizontal direction (tool feed direction) and vertical direction (perpendicular to tool feed direction). This greatly affects the form accuracy of the machined surface and its optical function. Traditional tool centre error identification is usually performed off-machine manually with high-precision instruments, which is time-consuming and labour-dependent. In this paper, a novel force-based 2D tool centre error identification method in SPDT is introduced. First, according to the relative position between the tool and workpiece centre, the tool centre error is classified into nine cases. The relation between the cutting force profiles and the tool centre error is analysed for each case. Then, a numerical fitting model and a geometric model are established to identify tool-above-centre and tool-below-centre errors, respectively. Additionally, a geometric model is established to calculate the normal distance from the tool interference/exit cutting to the workpiece centre, which serves as a reference for the horizontal tool centre error identification. Finally, the on-machine identification results of the 2D tool centre error are verified by experiments. Theoretical and experimental results show that the proposed on-machine 2D tool centre error identification method is effective and accurate, which greatly improves the cutting efficiency in SPDT. 相似文献
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以提高精密机床主轴回转误差的测量精度为研究目标,基于四点法矩阵算法,采用多圈重合式方法对主轴回转误差测量中的传感器输出数据进行处理。为提高传统遗传算法的收敛速度,降低优化结果对初始值的依赖性,对交叉和变异概率因子列式进行更新,并使用改进遗传算法对传感器安装角度和输出权值系数进行优化。使用改进遗传算法,收敛速率较传统遗传算法提高50%左右。利用多功能斜轨数控车床进行主轴径向回转误差测量及分离实验,分离后的标准芯棒形状误差值与标定值相比,误差在5%以内,且误差重复性低于5%。结果表明分离的结果精度较高,从而验证提出的算法的正确性和可行性。 相似文献
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几何误差是五轴数控机床重要误差源,针对传统测量方法仪器昂贵、测量周期长问题,提出基于球杆仪的五轴数控机床几何误差快速检测方法。对于机床的平动轴误差,利用多体系统理论及齐次坐标变换法,建立平动轴空间误差模型,通过球杆仪在同一平面不同位置进行两次圆轨迹,辨识出4项平动轴关键线性误差;针对五轴机床的转台和摆动轴,设计基于球杆仪的多条空间测试轨迹,完整求解出旋转轴12项几何误差。实验结果显示,所提方法获得转角定位误差与激光干涉仪法最大误差为0.001 8°,利用检测结果进行机床空间误差补偿,测试轨迹偏差由16μm降至4μm,为补偿前的25%,验证了方法的有效性。提出的五轴机床几何误差检测方法方便、便捷,适用于工业现场。 相似文献
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A method for evaluating spindle rotation errors of machine tools using a laser interferometer 总被引:3,自引:0,他引:3
This paper presents a method for assessing radial and axial error motions of spindles. It uses the Hewlett Packard 5529A laser interferometer. The measurement is made using reflection directly from a high-precision sphere. Such object is used as the optical reflector. The sphere is affixed at the end of a wobble device, which is clamped in the spindle. The principle of measurement is similar to that of a linear interferometer, except that the high-precision sphere is used in place of the usual retroreflector. A convergent lens is utilized to focus the laser beam to a small spot on the sphere surface. This minimizes the dispersion of the beam due to the reflection on the spherical surface. A software package has been developed for data acquisition and presentation of the error motion polar plots of the spindle. Application of this spindle error calibrator on a CNC machining centre is undertaken. The results are presented and discussed. 相似文献
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机械传动的轴承、齿轮等关键部位的故障信号中都含有冲击信息,通过对冲击信息的提取就可以对设备做出精密诊断.本文针对机械故障难以预先发现的问题,将离散小波变换和频谱分析相结合从机械的振动信号中提取非平稳信号,以此作为判断故障信号及类型的依据.从实际的应用效果看,利用离散小波变换技术提取冲击信号是非常有效的. 相似文献
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基于指数函数的机床主轴热误差补偿模型 总被引:1,自引:0,他引:1
《计算机集成制造系统》2015,(6)
在对机床主轴进行热特性分析的基础上,建立了基于指数函数的机床主轴轴向热误差补偿模型。该热误差补偿模型建模时间短、资金成本低,能够方便快捷地应用到工厂生产环境中。通过实验获得不同转速下的主轴轴向热变形数据。使用回归分析和最小二乘法建立了稳定状态下主轴轴向变形量和时间常数的估计方程,进而建立了基于指数函数的热误差补偿模型。该模型可以预测不同转速下主轴的轴向变形量。通过实验证明了该热补偿模型在机床主轴恒速运转和变速运转两种工况下均具有较高的精度。 相似文献
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本文介绍了神经网络和PID调节器的预测功能,提出了基于神经网络和PID调节器的主轴回转误差控制系统,实验表明该系统能有效地控制主轴回转误差对加工精度的影响. 相似文献
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Yang Li Wanhua Zhao Wenwu Wu Bingheng Lu Yubao Chen 《The International Journal of Advanced Manufacturing Technology》2014,72(9-12):1415-1427
Thermal error, especially the one caused by the thermal expansion of spindle in axial direction, seriously impacts the accuracy of the precision machine tool. Thermal error compensation based on the thermal error model with high accuracy and robustness is an effective and economic way to reduce the impact and enhance the accuracy. Generally, thermal error models are built only on temperatures at some points in the spindle system. However, the thermal error is also closely related to other working parameters. Through the theoretical analysis, the simulation, and the experimental testing in this paper, it is found out that thermal error is determined by multiple variables, such as the temperature, the spindle rotation speed, the historical spindle temperature, the historical thermal error, and the time lag between the present and previous times. In order to examine the performance of thermal error models based on multiple variables, two common methods are used for modeling—the multiple regression method and the back propagation network. The data for modeling are collected from experiments conducted on the spindle of a precision machine tool under various working conditions. The modeling results demonstrate that models established based on the multiple variables have better accuracy and robustness. It also turns out that data filtering before modeling can further improve the performance of the models. Therefore, models based on multiple variables with good accuracy and robustness can be very useful for the further thermal error compensation. In addition, by taking relative importance analysis of multiple variables based on standardized regression coefficients, the influence of each variable to the thermal error is revealed. The ranking of coefficients can also be used as a new criterion for the optimal temperature variable selection in the future research. 相似文献
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Weiguo Gao Lingtao Weng Jinyi Zhang Wenjie Tian Guanwei Zhang Yingjie Zheng Jinhe Li 《The International Journal of Advanced Manufacturing Technology》2020,106(11):4731-4744
Error compensation is one of effective and economical means to improve the machining accuracy of machine tools. The measurement accuracy of kinematic error 相似文献
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基于经验小波变换的机械故障诊断方法研究 总被引:14,自引:0,他引:14
经验小波变换(EWT)是一种新的自适应信号分解方法,该方法继承了 EMD 和小波分析方法的各自优点,通过提取频域极大值点自适应地分割傅里叶频谱以分离不同的模态,然后在频域自适应地构造带通滤波器组从而构造正交小波函数,以提取具有紧支撑傅立叶频谱的调幅-调频(AM-FM)成分。本文将该方法引用到机械故障诊断中,提出了一种基于经验小波变换的机械故障诊断方法,并与EMD方法进行了对比分析。仿真结果表明,经验小波变换方法明显优于EMD方法,能有效地分解出信号的固有模态。与 EMD 相比较,该方法具有分解的模态少,不存在虚假的模态,计算量小,且在理论上具有易理解性等特点。最后将该方法应用到转子碰磨故障诊断中,实验结果进一步验证了该方法的有效性,能够有效地揭示出碰磨故障数据的频率结构,区分碰磨故障的严重程度。 相似文献
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精度设计是提升机床加工精度的有效途径,而准确辨识关键几何误差并为其合理分配权重是实现精度设计的前提条件,因此,提出了一种识别关键几何误差的灵敏度分析方法。 首先基于多体系统理论建立了机床加工误差模型,并基于该模型构建了灵敏度分析模型,同时定义了一种新的灵敏度指标。 然后,通过仿真分析明确了第 10、17、22、24 和 37 项几何误差为关键几何误差,同时实现了对各项几何误差分配权重。 最后,通过补偿关键几何误差和全部几何误差的方式对“ S”形检测试件进行加工并对比其轮廓度误差,对比结果显示通过两种补偿方式获得的平均轮廓度误差在 3 条检测线上的差值很小,分别为0. 005、0. 004 和 0. 006 mm,因此证明了提出的灵敏度分析方法的正确性。 相似文献
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