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标准件装配质量包含零件类型、位置偏差、姿态偏差等多个指标,还具有部位多、类型复杂的特点,该文提出基于装配局部特征的检测模板结合机器视觉的产品装配质量智能检测方案。首先,分析鉴别产品质量需从类型、位置、角度方面进行检测,还须结合装配公差要求,研究标准件局部特征检测方法;其次,通过标准件局部特征检测对装配部件进行快速准确定位、利用数学模型进行鉴别,结合SURF算法确定主方向及特征点,实现标准件装配质量的快速智能检测;最后,构建机箱标准件装配质量检测装置,对多个不同型号ADLINK嵌入式机箱进行试验。结果表明:与全局检测相比,使用标准件装配质量的局部特征智能检测技术,检测时间可缩短86.31%,实现零漏检,识别正确率达100%。 相似文献
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纤维增强树脂基复合材料机翼结构复杂,往往存在明显的固化变形现象,严重影响机翼的装配和气动特性。本研究目的在于建立大型复合材料复杂结构的热校形工艺方法,解决复合材料机翼制造的变形控制问题。针对复合材料机翼的固化变形特点,设计了新的热校形夹具工装。在评价复合材料应力松弛特性的基础上,建立了大型复合材料机翼结构热校形工艺的有限元模拟方法,实现了对热校形后机翼结构残余变形的有效预报,分析了校形载荷、校形温度等关键工艺参数对校形效果的影响规律,形成优化的热校形工艺方案。模拟及实验结果表明,复合材料热校形工艺可以适用于大型复杂结构,复合材料机翼89.5%的固化变形被热校形工艺的残余变形抵消,达到机翼的装配和气动外形要求。 相似文献
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基于形位公差带的分布特征,对形状、位置要素变动情况进行研究,提出了一种在一维线性装配尺寸链下,判断模型中形住误差是否应当纳入装配误差累积计算的方法.在统计平方根模型的基础上,依据零件生产加工完毕后各形位要素变动的分布特性,提出了一种新的装配误差累积计算模型.采用此模型可实现包含形住误差的装配精度定量分析.给出的一个应用实例说明了所提出方法的有效性. 相似文献
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三坐标能否准确地测量出工件的同轴度影响着以后的装配,本文着重研究了PC-DMIS环境下不同的同轴度检测方法及其应用. 相似文献
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针对生产现场砂轮精度检测效率低的问题,我们研制了一种以单片机8031和传感器为核心的砂轮精度检测系统。它可以快速准确地测量打印被测砂轮的质量不平衡和精度等级,测试误差〈3%。 相似文献
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介绍了1种作为工厂机床检修中大尺寸蜗轮距累积误差的检测装置和检测方法,以及用计算机快速准确地进行数据处理。 相似文献
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软测量建模中建模数据的准确与否直接影响到模型的精度,因此通过对建模数据进行过失误差检测可以确保建模数据的质量.文中提出了一种基于聚类分析的过失误差检测方法,该方法脱离了传统检测方法依赖于机理模型的束缚,更好地适应软测量的特点.针对软测量建模过程中建模数据过失误差检测的特性提出了一种新的聚类方法,这种新方法依据各数据点到数据中心的欧氏距离进行聚类,可以有效地将过失误差从数据集中剔除.实验表明这种基于聚类分析的过失误差检测方法具有很好的效果. 相似文献
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针对目前半闭环车床加工内球面精度低、误差大的现状,研究进给系统刚度对加工误差的影响并提高内球面的加工精度.利用赫兹接触理论对进给系统刚度进行分析,建立了刚度的数学模型.分析了半闭环车床加工内球面的工艺过程,并推导了切削曲面过程中进给系统受力状况,给出了误差表达式.通过对加工误差模型的仿真研究,结果表明进给系统刚度所产生的加工误差与刀位点和母线圆弧形状有关,所产生的误差可通过增发运动脉冲补偿.提出了一种引进补偿机制的插补运算方法,为提高内球面加工精度提供了理论上的指导. 相似文献
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精密测量螺旋面任意截形的一种方法 总被引:1,自引:1,他引:0
对螺旋面任意截形测量中的测球半径补偿方法进行了探讨,推导出了用球形测头测量螺旋面任意截形的通用补偿计算公式,从理论上修正了由测头半径所造成的测量误差,为螺旋面齿形的精密测量提供了一种实用方法。 相似文献
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Pascal J. Frey Houman Borouchaki 《International journal for numerical methods in engineering》1999,45(1):101-118
This paper proposes a method to evaluate the size quality as well as the shape quality of constrained surface meshes, the constraint being either a given metric or the geometric metric associated with the surface geometry. In the context of numerical simulations, the metric specifications are those related to the finite element method. The proposed measures allow to validate the surface meshes within a general mesh adaption scheme, the metric map being usually provided via an a posteriori error estimate. Several examples of surface meshes are proposed to illustrate the relevance of the approach. Copyright © 1999 John Wiley & Sons, Ltd. 相似文献
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In this work axisymmetric components are scanned using Coordinate Measuring Machine (CMM) and modeled using circular section/boundary curves. Surface options such as Surfaces of revolution, lofted surface and coons surface are considered in modelling. The curve length and volume are numerically evaluated for various surface options. The error percentage is obtained for curve length and volume by taking the values measured from the components as reference values. Result are presented for six different circumferential curves shapes viz., parallel (cylindrical), inclined upwards (inverted frustum), inclined downwards (frustum), convex (barrel), concave (sand-clock shape) and combined convex-concave shape. The results show that percentage error is negligible only for Surfaces of revolution and lofted surface in modelling convex, concave and combined convex-concave shapes. In modelling parallel and inclined shapes all three surface options fit well. In modelling convex, concave and combined convex-concave shapes, coons surface does not fit well. The suggestion to designers is to use surfaces of revolution and lofted surface rather than using coons surface. Otherwise the shapes of components will be different from the designed shape. Also the volume of components will be different from the designed volume. In such cases the designed components fail to meet the shape and volume requirements. 相似文献
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A. A. Pashilkar 《Sadhana》2001,26(6):495-515
A new aerodynamic modelling approach is proposed for the longitudinal static characteristics of a simple delta wing. It captures
the static variation of normal force and pitching moment characteristics throughout the angle of attack range. The pressure
model is based on parametrizing the surface pressure distribution on a simple delta wing. The model is then extended to a
wing/body combination where body-alone data are also available. The model is shown to be simple and consistent with experimental
data. The pressure model can be used as a first approximation for the load estimation on the delta wing at high angles of
attack. 相似文献
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NURBS曲面的四边形网格的分割与逼近 总被引:4,自引:1,他引:3
介绍了一个用于对NURBS曲面进行四边形网格的分割与逼近的算法。该算法采用二叉树递归分割的方法分割和逼近曲面,所分割的四边形除了在高度方向和曲面边界处满足给定精度外,同时在四边形四条边界满足给定的切矢精度。实例测试结果表明,用本文所述算法生成的四边形网格具有网格逼近原曲面、网格四边形接近于规则四边形等特点。 相似文献
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Freeform surfaces have been widely used in various engineering applications. Increasing requirements for the accuracy of freeform surfaces have led to significant challenges for the manufacturing of these surfaces. A method for manufacturing of freeform surfaces is introduced in this paper by integrating inspection and tool path generation to improve manufacturing quality while reducing manufacturing efforts. Inspection is conducted by comparing the digitised manufactured surface with the design surface to identify the error regions. In this new inspection technique, the areas on the manufactured surface that are beyond the design tolerance boundaries are used as the objective function during the localisation process, in order to minimise post-inspection machining efforts. The tool path generation methods are then selected based on the geometric characteristics of the identified error regions, for creating tool paths to remove the errors. Computational efficiency, machining efficiency, and quality are considered in this integrated method. 相似文献
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详细介绍了三平(球)面互检法、双球面法、旋转平均法、平移差分法(伪剪切干涉法)、奇偶函数
法、随机球法和旋转平移法等光学面形绝对检测方法的测量原理,针对不同方法简述了国内外绝对检测技术的
发展动态,并对比了不同绝对检测方法的适用领域以及存在相应的技术限制。从物理实现和算法两方面对绝对
检测技术的未来发展趋势进行展望,提出了通过提高外部机械结构精度来增加面型绝对检测精度,分析了深度
神经网络算法与计算光学成像技术两种方法在绝对检测过程中的优势,并提出通过将两种方法与绝对检测技术
相结合可进一步提高光学面形的绝对检测精度,为绝对检测相关领域的研究提供有益参考。 相似文献