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介绍数控机床三维空间定位精度测量、补偿和校验的一种高效、精确的方法。通过激光多普勒干涉仪,运用矢量原理和多步测量的方法,通过四次调整测量就可以获得机床的12项误差元素,根据测量出的误差数据可以生成误差补偿代码并用于误差补偿以提高机床三维空间定位精度,最后通过实例验证该测量方法的准确性及高效率。 相似文献
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本文介绍一种使用美国光动公司的激光多谱勒位移测量仪,对数控机床进行空间误差检测的激光矢量测量新方法。该方法可以方便而快速地检测出机床的空间定位精度,包括3个定位误差、6个直线度误差和3个垂直度误差;同时还可以根据测量的空间定位误差数据生成误差补偿的代码,进而可以对其进行空间定位误差的补偿,大幅度提高了数控机床加工精度。 相似文献
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Dr E. S. Lee H. G. Wi 《The International Journal of Advanced Manufacturing Technology》1998,14(5):330-335
A method for measuring the accuracy of rotating objects was studied. Rotating axis errors are significant; such as the spindle error of a machine tool which results in increased surface roughness of machined work pieces. Three capacitance-type displacement sensors were used to measure the position of a rotating master ball. The sensors were mounted at the three orthogonal points on the spindle axis. The measurement data were analysed for rotating spindle accuracy, not only for the average roundness error but also for the spindle volumetric positional error during rotation. This method is simple and economical for industrial field use for regular inspection of spindles using portable equipment. The time taken for measurement and analysis using this method is only about two hours. This method can also measure microscopic amplitudes in 3-D directions of vibrating objects. 相似文献
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The tracking interferometer, or the laser tracker, is a laser interferometer with a steering mechanism to regulate the laser beam direction to follow a retroreflector (“target”). Applying the multilateration principle, it measures the target's three-dimensional position at an arbitrary location in the workspace. Its application to the volumetric accuracy measurement for coordinate measurement machines or machine tools has been long studied. In this paper, we propose the ‘open-loop’ tracking interferometer, where the laser beam is regulated toward the command target position. This eliminates the automated tracking mechanism and thus may significantly reduce the manufacturing cost of conventional tracking interferometers. The objective of this paper is to validate this ‘open-loop’ tracking interferometer concept by investigating its measurement uncertainty both experimentally and analytically. To simplify the problem, this paper focuses on the measurement of the target's two-dimensional position by using a single-axis ‘open-loop’ tracking interferometer prototype. 相似文献
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Error analysis and compensation for the volumetric errors of a vertical machining centre using a hemispherical helix ball bar test 总被引:2,自引:1,他引:2
S.-H. Yang K.-H. Kim Y. K. Park S.-G. Lee 《The International Journal of Advanced Manufacturing Technology》2004,23(7-8):495-500
Machining accuracy is directly influenced by the quasi-static errors of a machine tool. Since machine errors have a direct effect upon both the surface finish and geometric shape of the finished workpiece, it is imperative to measure the machine errors and to compensate for them. A laser measurement system to identify geometric errors of a machine tool has disadvantages, such as a high cost, a long calibration time and the usage of a volumetric error synthesis model. In this study, we proposed a novel analysis of the geometric errors of a machine tool using a ball bar test without using a complicated error synthesis model. Also, a statistical analysis method was employed to derive geometric errors using a hemispherical helix ball bar test. According to the experimental result, we observed that geometric errors of the vertical machining centre were compensated by 88%. 相似文献
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This paper presents an uncertainty analysis of a Positional Error Calibrator based on a laser interferometer system. This laser calibration system is capable of evaluating the positioning accuracy of a numerically controlled axis of machine tools and coordinate measuring machines (CMM) under dynamic conditions. In order to assess the measurement uncertainty of this calibrator, an analysis of the uncertainty components that make up the uncertainty budget of this calibrator has been carried out. These uncertainty components can be classified into three categories as follows: (1) uncertainties intrinsic to the laser system; (2) uncertainties due to environmental effects; (3) measuring uncertainties due to the installation. The procedure for evaluating the uncertainty of this calibrator follows GUM (“Guide to the Expression of Uncertainty in Measurement”). This uncertainty analysis was carried out when this calibrator was used to assess the positional errors of the “X” axis of a moving bridge type CMM. 相似文献
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为了解决超声测距角度引入的误差难以有效补偿的问题,基于函数逼近理论和方法,提出了一种超声测距角度引入误差的补偿方法。首先对超声脉冲的传播和入射过程进行了仿真,仿真结果说明不同测距角度下的超声脉冲的传播速度不同,成为引入误差的媒介。然后通过实验分析了此媒介作用下的测距角度与误差的相关关系,采用基函数模型组合的方法构建了超声测距角误差模型。最后,针对模型自变量(测量距离和测距角度)必须是已知值,不能在实际中实现误差补偿的问题,将测距的测量值作为迭代运算的变量,将模型作为迭代运算的关系式,设计了一种超声测距角度引入误差的补偿算法。经实测验证,该算法在测距角度变化时,可以使测距误差的均值小于1.1 mm,有效地补偿了测距角度引入的误差,提高了超声定位的精度。 相似文献
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In this paper, an on-machine error calibration method, covering error modeling and measurement, is proposed to evaluate and compensate the errors caused by the mechanical and optical system equipped in the micromachining center using the femtosecond laser. Through preliminary tests by dicing silicon wafer, it has revealed that the squareness, laser beam misalign and focal position offset, are the main causes to result in the inaccuracy of micromachining. Consequently, an error modeling method is proposed to evaluate the error distribution in the workspace, and hereafter a comprehensive error vector of the laser beam, combining the squareness errors of Z-axis with the laser beam misalign, is generated by the variable substitution method. Subsequently, an increment error model in the instant local coordinates is established to satisfy the requirement of the programming method commonly used in the laser machine tools. Furthermore, a series of holes and grooves are machined on the femtosecond laser micromachining center to validate the proposed approach and model. The machining dimensions including diameters, distances and angles, are measured on-machine to identify the squareness errors, laser beam misalign and focal position offset according to the proposed error model. Finally, the experimental results show that, comparing to the uncompensated tests, the machining accuracy has been significantly improved with the proposed method. 相似文献
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A tracking interferometer is a laser interferometer with the mechanism to steer the laser direction to automatically follow a target retroreflector. This paper experimentally investigates the performance of the tracking interferometer prototype, developed by a part of the authors, in estimating the volumetric accuracy of a machining center based on the multilateration principle. Then, the prototype's technical issues are discussed based on the measurement uncertainty analysis. This paper briefly reviews the direct algorithm to calculate the three-dimensional position of the target, as well as the indirect algorithm to estimate geometric error parameters of the machine's kinematic model. Their comparison is also presented based on the uncertainty analysis. 相似文献
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In this paper, we present a new statistical approach towards soft geometrical error compensation of machines with significant errors. The approach, based on an analysis of the probability of the random error recurring, can reduce the adverse influence of random errors on the compensation of systematic errors. The proposed methodology is made up of three steps. First, error classes are defined from the error bands obtained from calibration. Second, the probability of the magnitude of random error belonging to each of these classes is computed based on the density of the data set within the class. Based on these probabilities, the most probable systematic part of the error measurement can be statistically deduced. Finally, the geometrical error compensation is carried out based on this value. Experimental results are provided for the linear error compensation of a single-axis piezo-ceramic motion system. 相似文献
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The evaluation of the volumetric accuracy of a machine tool is an open challenge in the industry, and a wide variety of technical solutions are available in the market and at research level. All solutions have advantages and disadvantages concerning which errors can be measured, the achievable uncertainty, the ease of implementation, possibility of machine integration and automation, the equipment cost and the machine occupation time, and it is not always straightforward which option to choose for each application. The need to ensure accuracy during the whole lifetime of the machine and the availability of monitoring systems developed following the Industry 4.0 trend are pushing the development of measurement systems that can be integrated in the machine to perform semi-automatic verification procedures that can be performed frequently by the machine user to monitor the condition of the machine. Calibrated artefact based calibration and verification solutions have an advantage in this field over laser based solutions in terms of cost and feasibility of machine integration, but they need to be optimized for each machine and customer requirements to achieve the required calibration uncertainty and minimize machine occupation time.This paper introduces a digital twin-based methodology to simulate all relevant effects in an artefact-based machine tool calibration procedure, from the machine itself with its expected error ranges, to the artefact geometry and uncertainty, artefact positions in the workspace, probe uncertainty, compensation model, etc. By parameterizing all relevant variables in the design of the calibration procedure, this simulation methodology can be used to analyse the effect of each design variable on the error mapping uncertainty, which is of great help in adapting the procedure to each specific machine and user requirements. The simulation methodology and the analysis possibilities are illustrated by applying it on a 3-axis milling machine tool. 相似文献
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This paper aims to present different techniques and factors that affect the measurement accuracy of a commercial laser tracker responsible for capturing checkpoints used in machine tool volumetric verification. This study was conducted to uncover various sources of error affecting the measurement uncertainty of the laser tracker, additional sources of error that further contributed to the uncertainty, and the factors influencing these techniques. We also define several noise reduction techniques for the measurements.The improvement in the accuracy of captured points focuses on a multilateration technique and its various resolution methods both analytically and geometrically. Similarly, we present trilateration and least squares techniques that can be used for laser tracker self-calibration, which is an essential parameter in multilateration.This paper presents the influence of the spatial distribution of laser trackers (LTs) in measurement noise reduction by multilateration, which produces an improvement in volumetric error machine tool reduction. A study of the spatial angle between LTs, the distance and the visibility of the point to be measured are presented using a synthetic test. All of these factors limit the scope of multilateration. Similarly, a comparison of self-calibration techniques using the least squares and trilateration methods with which to determine the relative position of the laser tracker employees is presented. We also present the influence of the relationship between the radial and angular measurement noise self-calibration processes as it relates to the volumetric error reduction achieved by the machine tool with multilateration. All studies were performed using synthetic tests generated using a synthetic data parametric generator. 相似文献
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本文从幅度重心公式入手,提出了一种新的校准算法,建立了三元组辐射信号幅度补偿表格,从而提高射频仿真系统在低频段时的定位精度。此方法已成功应用于某研究所射频仿真系统,取得了良好的效果。 相似文献