共查询到17条相似文献,搜索用时 171 毫秒
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三坐标测量机在高速测量时,由于附加惯性力的影响,引起机体变形,从而导致动态误差.对三坐标测量机动态误差进行了理论分析,在加速、匀速、减速三种状态下,利用有限元方法对横梁沿Z方向进行了受力变形分析,推导出此三种载荷下动态误差补偿模型,并由此得出了任意载荷作用下的误差补偿模型,提高了三坐标测量机的测量精度. 相似文献
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三坐标测量机动态误差混合建模方法 总被引:3,自引:1,他引:2
为了建立高精度的三坐标测量机相关性动态误差修正模型,应用偏最小二乘回归法和支持向量机研究动态误差混合建模方法,分析了三坐标测量机的动态误差来源及特点,介绍了偏最小二乘回归法和支持向量机的基本原理及算法,编制了相应的混合建模软件.应用双频激光干涉仪设计了测量机动态误差实验装置,进行了相应的误差分离实验.应用偏最小二乘法确定测量机动态误差主要影响因素,得出坐标变量y、z和x是主要影响因素、测量速度v是次要影响因素的结论.结合主要影响因素分析结果,应用支持向量机和动态误差实验数据建立了测量机的空间动态误差模型,并进行比对和验证,应用混合建模方法建立的修正模型精度可以达到±0.02 μm,高于未利用偏最小二乘法±0.75 μm的建模精度,完全可以用于三坐标测量机相关性动态误差的高精度建模. 相似文献
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针对柔性臂坐标测量机误差因素复杂且误差影响之间呈非线性的问题,分析了误差因素并对部分动态误差进行研究,提出了一种基于模拟退火和神经网络的柔性臂坐标测量机动态误差补偿方法。利用BP神经网络建立动态误差补偿模型,通过模拟退火算法优化权值从而解决了神经网络的收敛速度慢的问题。通过实验获得数据样本,训练所建模型后对测试数据进行误差补偿。与BP神经网络模型进行对比结果表明,补偿测试点后得出的单点重复性测量误差提高了60.85%,长度测量误差的精度提高了54.79%,证明了所提方法的有效性和可行性。 相似文献
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研究了影响快速探测坐标测量机动态测量精度的特性参数与测量精度之间的关系.通过实验分析了移动速度和测量位置对测量机定位误差的影响,以及测头DDC参数对测头等效作用直径的影响.研究结果表明:测量机的动态测量误差重复性好并可以修正;由于不同移动速度下,气浮导轨刚度和不同驱动电机加速度曲线引起的桥架附加振动不同,因此不同结构测量机存在不同最佳临界移动速度;测量机沿不同方向触测时,存在与移动速度有关的不同最佳测量空间;逼近距离对测头等效作用直径d的影响远远大于触测速度和移动速度对d的影响. 相似文献
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本文研究了三坐标测量机在高速测量过程中的动态误差。以一台移动桥式三坐标测量机为例,分析了其动态误差的产生原因,建立了其动态误差的数学模型,并对动态误差进行了全面的测量和补偿。实验证明,三坐标测量机的动态误差具有一定的重复性,可用软件补偿,从而提高三坐标测量机快速测量的精度。 相似文献
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ASSESSING THE DYNAMIC ERRORS OF COORDINATE MEASURING MACHINES 总被引:2,自引:0,他引:2
0INTRODUCTIONCoordinatemeasuringmachines(CMMs)arewidelyusedinthedevelopingmodernmanufacturingindustry.Inmanycases,fastproduc... 相似文献
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Tugrul Özel 《The International Journal of Advanced Manufacturing Technology》2006,27(9-10):960-968
One of the major sources that affect measurement accuracy and limit the use of high motion speeds in coordinate measuring machines (CMM) is the position error. In fact, static and dynamic probe errors are more direct factors in measuring machine accuracy, but are not the subject of this research. However the accuracy of acquisition of component position errors using a CMM in motion is also of importance, hence the dynamics of a CMM need to be considered. Therefore, this research aims to model the dynamics of a horizontal arm CMM by considering drive flexibility at joints and evaluates the characteristics of the system for fine motion control purposes. Design of a precision tracking controller (PTC) to perform superior tracking for enhancing the measurement accuracy and the probing speed in providing less inspection time at high motion speeds is carried out. A dynamic model for the CMM is developed including drive flexibilities represented with lumped springs at the joints. Due to the non-collocated nature of the control scheme in the flexible CMM dynamics, a non-minimum phase system is observed in the proposed CMM model. Using the derived CMM model with joint flexibilities, tracking motion control simulations are conducted at different probing speeds for the cases where a PI controller and a feedback PTC are employed. A comparison of the PI controller with the feedback PTC is also performed. Results demonstrate that the effects of joint flexibilities on the contour error and probing speeds are significant and the PI controller is not capable of providing good accuracy during challenging tasks such as corner tracking. However, the simulation results indicated that by using the proposed feedback precision tracking controller, contour errors in corner tracking that are caused by joint flexibilities can be reduced effectively . 相似文献
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Quasi-stiffness model is effective for the compensation of the geometric errors of coordinates measuring machines (CMMs) in slow probing, but degrade the error compensation accuracy due to the generation of dynamic errors in fast probing. It is usually regarded that acceleration is the major origin of dynamic errors; and yet the dynamic effects that rise from the quick fluctuation of geometric errors in fast probing had attracted little attentions. This paper presents a model for the dynamic effects of the geometric errors of CMMs in fast probing, and investigates their properties with experiments. The error model is built with recursive least squares (RLS) identification technique by taking probing acceleration and the 6 geometric errors of X slideway for the inputs while the positioning error of probe tip for output. Then the positioning error of probe tip is decomposed into 7 components corresponding to the 7 inputs. Analyses on the experiments show that the angular errors around Y and Z axes, εY(x) and εZ(x), can induce remarkable dynamic effects, especially in a CMM with low stiffness air bearing. Error compensation with RLS identification seems feasible theoretically, but it is not recommendable due to the veracity uncertainty of identification. Nevertheless smoothening the sharp corners of the curves of geometric errors, especially εY ∼ x and εZ ∼ x, in terms of probing speed and Y coordinates of probe tip is considered as a simple but effective and reliable method to improve the accuracy of CMMs errors compensation in fast probing. 相似文献
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Ye Li Naveen P. Surisetti Joseph C. Chen 《The International Journal of Advanced Manufacturing Technology》2013,64(5-8):875-887
Coordinate measuring machine (CMM) has been extensively used in surface measurement and inspection. CMM produces more accurate and reliable results compared with non-contact measurement devices, since CMM measures target surfaces in a tactile way and is not affected by surface reflection quality. However, when there is porosity on the outside surfaces, CMM measurement will have errors because part of the probing stylus will come into the porosity spaces. This paper presents a method of using CMM to measure external profiles of objects with external porosity spaces. The center of a CMM probing stylus will be compensated to avoid porosity spaces and located above external surface areas along surface normal directions. Such a probing strategy can be implemented in both computer-aided design (CAD)-guided mode and non-CAD-guided mode. When the CAD model is available, the probing styli are guided to approach the surface along its normal directions successively to identify and avoid porosity spaces. When the CAD model is unavailable, surface normal directions will be estimated first and then adjusted. The presented method is able to avoid porosity spaces in CMM measurement regardless of the availability of CAD models. 相似文献
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三环减速器环板惯性力平衡和实验研究 总被引:11,自引:0,他引:11
分析了三环减速器环板惯性力对动力性能的影响,提出了平衡惯性力的方法,通过实验证明了惯性和不平衡是引起振动的主要原因,并可以通过配重平衡来改善运动平稳性。 相似文献