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数控机床线性轴定位与重复定位精度的检测 总被引:1,自引:0,他引:1
介绍了使用英国RENISHAW公司生产的激光双频干涉仪检测数控机床的线性轴定位与重复定位精度的方法,并就检测中出现的具体问题给出了解决方法。 相似文献
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滚珠丝杠螺距误差补偿法提高数控机床定位精度的研究 总被引:2,自引:0,他引:2
在详细论述、对比了实现数控机床滚珠丝杠螺距误差补偿的硬件、软件方法的原理基础上,对滚珠丝杠螺距误差软件补偿法可有效提高数控机床的定位精度进行了试验验证。 相似文献
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介绍了用标准时间间隔发生器检定秒表时,测量结果不确定度分析和评定过程;讨论了测量不确定度的几个主要来源;通过一组实例,给出了秒表检定不确定度的分析和评定结果,该过程和结论可应用在对于计量标准进行相应指标的不确定度分析上,也可用于估计秒表检定本身的不确定度。 相似文献
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通过对钟罩式气体流量标准装置的不确定度分析,确定了该标准装置的合成标准不确定度和扩展不确定度,为气体流量计的检定提供了依据。 相似文献
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考虑球轴承接触角测量仪的自身动态特性、轴承外圈的试验转速、试验加载力对测量仪测量精度的影响,建立了测量仪的动态不确定度计算模型。针对小样本试验测试结果,采用灰色理论的方法评价了球轴承接触角测量结果的不确定度。基于不确定度的分离原理,分离出测量仪的自身动态特性、外圈转速、试验加载力对测量不确定度的影响规律,建立了接触角测量的动态不确定度计算模型,并通过实际算例验证了模型。建立的测量仪动态不确定度计算模型可用于预测不同工况下的接触角测量不确定度,有助于及时对测量仪进行相应的校准,以提高接触角测量结果的精度。 相似文献
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方波幅度的测量不确定度 总被引:3,自引:1,他引:3
介绍了用众数法评价方波幅度时的不确定度分析和评价过程;讨论了主要的不确定度来源,包括众数判别区间的影响、波形测量系统幅度测量误差的影响等等;给出了减小不确定度的主要措施,并结合一个实例,给出了方波幅度的不确定度评价结果。 相似文献
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CAM后置处理研究 总被引:1,自引:0,他引:1
唐立山 《航空精密制造技术》2006,42(3):60-62
分析了数控加工后置处理技术的特征、面临的问题和当前的发展趋势,介绍了应用通用后置处理器开发定制专用后置处理器的实践。 相似文献
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徐家文%朱永伟%胡平旺%云乃彰%严德荣 《宇航材料工艺》2003,33(1):13-17
综述了整体叶轮的主要加工方法及其比较,就数控展成电解加工的重要技术特点(可以综合发挥数控技术和电解加工两者的技术优点)进行了论述,展示了数控电解在加工整体叶轮、解决以数控铣、精密铸造难加工或不能加工的技术难题方面所显示的优越性。该项工艺技术对于新型航天发动机的研制具有重要意义和广阔的应用前景。 相似文献
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针对导弹飞行中的舵伺服系统所存在的不确定性和非线性时变等特点,采用常规控制系统难以适应这种不确定性,文中提出采用现代控制理论与经典相结合的方法——自适应神经网络CMAC与PID并行控制对舵机伺服系统进行优化设计。首先,在分析舵系统基础上,设计出了具有一定适应性的舵伺服系统的总体方案;然后,建立了基于CMAC与PID并行控制的舵系统控制器;最后,经MATLAB仿真,结果表明并行控制能够较好适应多种不确定性;并能够快速准确的对舵机进行跟踪控制。 相似文献
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三元流闭式叶轮组合电加工技术研究Ⅰ——总体方案设计及关键技术 总被引:1,自引:1,他引:0
针对难切削材料三元流闭式叶轮上复杂弯扭型腔的加工难题,提出数控电解(NC-ECM)/数控电火花(NC-EDM)组合加工数字化制造技术方案。本文重点论述了其总体方案设计及关键技术,包括总体工艺流程设计,数控电解预加工中阴极及运动轨迹设计,数控电火花精加工中电极及加工轨迹设计,工装夹具设计以及加工参数的选择与优化等问题。成功试制了合格的某型三元流闭式叶轮,试验结果表明,组合电加工技术能够满足三元流闭式叶轮的实际生产要求。 相似文献
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Precise modeling of arc tooth face-gear with transition curve 总被引:2,自引:0,他引:2
A fabrication method is adopted for which an imaginary gear simultaneously realizes conjugated meshing with an arc tooth cylindrical gear and an arc tooth face-gear. The cutter fillet and tooth crest edge form the tooth root fillet of the gear, and the linear tooth surface equation of the imaginary gear and the position vector of the curvature center of the cutter fillet arc constructed with certain cutter inclination to deduce a working arc tooth surface equation. The tooth root fillet equation of the arc tooth face-gear is derived from the meshing geometry and kinematics. A numer- ically controlled machining model of the arc tooth face-gear is established through the transforma- tion of adjustment parameters from the cutter-tilt milling machine to a common multi-axis NC machine. Motion parameters of each movement axis of the NC machine are acquired. A processing example is presented to verify the precision of the fabrication method in processing the arc tooth face-gear. The method provides a theoretical and tentative basis for the analysis of tooth surface contact stress, tooth root bending stress and dynamics. A hobbing test is conducted to demonstrate the good meshing condition of the arc tooth face-gear pair. 相似文献
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用模糊数描述节点的多种故障状态,用模糊子集描述根节点的故障概率,用贝叶斯网络的条件概率表描述节点间的不确定关系,构建数控机床故障的模糊贝叶斯网络;采用桶消元算法,对数控机床故障的模糊贝叶斯网络进行推理和计算,获得根节点的后验概率,为数控机床故障诊断与分析提供依据;最后,以数控机床刀架系统故障的贝叶斯网络推理过程为例,验证所提理论和方法的有效性。 相似文献
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《Aerospace Science and Technology》2003,7(4):289-297
The drag of airfoils has long been determined from measurements in the wake behind the airfoil. The well-known formula of Squire and Young can be used to transfer the measured data to infinity downstream of the airfoil, where an exact relation to the drag exists. The Squire–Young formula is reviewed and an uncertainty in its derivation is discussed. A new formula of the same type is then derived, which also contains an uncertainty. This uncertainty can be reduced by experimental and numerical investigations of the wake displacement. Conversely, the displacement and the momentum of the wake must be investigated to reduce the uncertainty of the Squire–Young formula. In the second part of the paper, the determination of the drag directly by integration of the skin friction is investigated. Such a calculation is not difficult if the boundary-layer characteristics are computed numerically. An additional pressure drag must be regarded in this case. A new formula for the pressure drag is derived which shows that the uncertainty of the Squire–Young type formulas is contained in the evaluation of the pressure drag. This is another reason for further research on wake displacement. 相似文献
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直纹面叶轮刀具轨迹规划的研究(英文) 总被引:2,自引:1,他引:1
Liang Quan Wang Yongzhang Fu Hongya Han Zhenyu School of Mechatronics Engineering Harbin Institute of Technology Harbin China 《中国航空学报》2008,21(5):462-471
At present, most commercial computer-aided manufacturing (CAM) systems are deficient in efficiency and performances on generating tool path during machining impellers. To solve the problem, this article develops a special software to plan cutting path for ruled surface impellers. An approximation algorithm to generate cutting path for machining integral ruled surface impellers is proposed. By fitting sampling data points of an impeller blade into a curve, a model of ruled surface blade of an impeller is built up. Furthermore, by calculating the points where the cutter axis vector intersects the free-form hub surface of an impeller, problems about, for instance, the ambiguity in calculation and machining the wide blade surface with a short flute cutter are solved. Finally, an integral impeller cutting path is planned by way of an integrated cutter location control algorithm. Simulation and machining tests with an impeller are performed on a 5-axis computer numerically controlled (CNC) mill machine, which shows the feasibility of the proposed algorithm. 相似文献