定位误差的产生及提高定位精度的研究

从工件在夹具加工时获得工序尺寸精度的原理出发，总结出较切实质的定位误差产生的原因和消除定位误差的三基准重合原则以及提高工件定位精度的方法。     

机构位置误差和夹具定位误差的统计分析法

由于实际机构构件存在固有误差,理想机构是不存在的。当实际机构与理想机构的主动件处在相同的位置时,机构从动件位置的误差即为机构的位置误差。而在工件的定位系统中。由于各方面固有误差的存在,使工件的定位基准在空间的实际位置相对理想位置存在着位置误差。这部分误差在定位误差的计算中称作基准位移误差。传统的定位     

关于定位误差产生原因的探讨

本文在全面分析关于机械加工中定位误差产生原因有关例证的基础上,对工件在调整法加工中产生定位误差的原因作了较为深入的分析。并得出了判断产生定位误差的充要三条件和产生定位误差的根本原因。     

定位误差的计算机数据处理

以实际生产中一典型零件的加工为例，分析工件以“一面两孔”定位时的定位误差，得到当被加工孔与定位孔位置关系不同时产生的定位误差的计算公式，用C语言编制计算程序，利用计算机对定位误差进行数据处理，从结果分析中，找出减小定位误差的方法。     

定位误差的运动学解释及工件以回转面定位的定位基准

本文阐明了当工件以回转面定位，计算定位误差时，取定位基准或为回转面某一母线，或为其中心线，计算结果是相同的。进而从运动学原理上对定位误差进行了解释。     

定位误差的运动学解释及工件以回转面定位基准

本文阐明了当工件以回转面定位，计算定位误差时，取定位基准或为回转面某一母线，或为其中心线，计算结果是相同的。进而从运动学原理上对定位误差进行了解释。     

关于典型工件加工定位误差的计算结果比较

对工件在夹具定位误差的定义、原因;进行解释的基础上,列举典型计算方法进行比较,得出误差合成法优于极限位置法。     

锁头加工组合机床夹具的设计

着重阐述了锁头组合机床的夹具设计,对锁头工件的定位、定位误差、夹紧力、各机构的结构设计做了全面的分析及计算.     

对定位误差概念的探讨

本文对机床夹具中的定位误差,提出应为:一批工件的工序尺寸、工序角度极限值之差的明确概念。     

固定支承无心磨削成形周期性误差的研究

通过对固定支承外圆无心磨削时工件表面产生周期性误差及固定支承角的大小对定位误差影响的原因分析,提出了利用调整固定支承角的方法提高磨削加工精度的途径,指出在零件生产规模达到一定批量时,应首先找出零件上原始形状误差的分布规律,在此基础上,通过优化调整无心磨床支承角,使工件原始周期性形状偏差引起的周期性形状误差达到最小化.     

机床夹具误差的微分分析法

在机床夹具设计中，经常需要进行误差的分析和计算，在有关夹具研究和设计的资料中，多数采用几何作图法来完成，本文采用“微分分析法”。通过微分运算来确定夹具的误差，使分析工作概念清楚，方法统一，运算简便。     

快速反应式双偏心轮定位机构的分析计算

介绍了双偏心轮定位夹具的工作原理和设计计算公式双偏心轮定位夹具具有快速反应功能,可允许工件直径在较大范围内变化,能较好地适应现代生产方式对夹具的要求     

Accuracy characterization and measurement point planning for workpiece localization

1 Introduction In manufacturing literature, workpiece localization is a problem as follows: assum-ing a rigid workpiece is arbitrarily fixtured to a machine table, determine the positionand orientation of the workpiece frame relative to a known machine frame from a set ofcoordinates measured on the datum surfaces of the workpiece. Localization establishes adesired spatial relationship of the workpiece with respect to the machine table withunique and accurate pose. Workpiece localizatio…     

浮动V型块减少圆柱面上通槽加工误差的定位方案

文章分析了常用固定V型块独立限位造成定位误差的原因。在通过探究支承板限位的定位误差以及定位元件不同固定形式的定位误差的基础上,提出了一种新定位方案。通过计算和比较得出,新方案的定位误差小于用V型块独立限位的定位误差。     

定位元件制造误差对定位精度影响的探讨

本文通过对零件安装实例的分析计算，得出定位零件制造误差对定位精度影响的诸因素。并就同一工序中夹具的使用情况进行讨论，认为当使用单套夹具时，定位元件误差是其制造允差范围内的一个定值；当使用多套夹具时，应考虑定位元件制造允差范围内两个极限状态对定位精度的影响。     

Prediction of diameter errors compensation in bars turning

On the basis of analyzing the machine-workpiece-tool system, the main factors affecting diameter errors in bars turning are considered, and the mathematic models of the actual workpiece diameter at the cutting point are established according to the three usual methods of mounting workpieces on a turning machine. Further a predictionsystem for diameter errors is developed; a new method, called discrete nodes output, is presented and applied to expressing workpiece diameter errors at given points along the part axis, then off-line compensation is implemented according to the prediction values to diminish machining errors. The results indicate that the method can diminish diameter errors more than 70%, greatly improve the machining accuracy of bars.     

即车型夹具在机械加工中的应用

介绍了一种简易夹具，该夹具适用于盘壳类零件的批量加工，降低了夹具的生产成本且提高了夹具的加工精度。     

Prediction of diameter errors compensation in bars turning

On the basis of analyzing the machine-workpiece-tool system, the main factors affecting diameter errors in bars turning are considered, and the mathematic models of the actual workpiece diameter at the cutting point are established according to the three usual methods of mounting workpieces on a turning machine. Further a prediction system for diameter errors is developed; a new method, called discrete nodes output, is presented and applied to expressing workpiece diameter errors at given points along the part axis, then off-line compensation is implemented according to the prediction values to diminish machining errors. The results indicate that the method can diminish diameter errors more than 70%, greatly improve the machining accuracy of bars. Foundation item: Projects (50175081 and 50475117) supported by the National Natural Science Foundation of China; project (033181611) supported by the Tianjin Municipal Science and Technology Commission     

An approach to error elimination for multi-axis CNC machining and robot manipulation

The geometrical accuracy of a machined feature on a workpiece during machining processes is mainly affected by the kinematic chain errors of multi-axis CNC machines and robots, locating precision of fixtures, and datum errors on the workpiece. It is necessary to find a way to minimize the feature errors on the workpiece. In this paper, the kinematic chain errors are transformed into the displacements of the workpiece. The relationship between the kinematic chain errors and the displacements of the position and orientation of the workpiece is developed. A mapping model between the displacements of workpieces and the datum errors, and adjustments of fixtures is established. The suitable sets of unit basis twists for each of the commonly encountered types of feature and the corresponding locating directions are analyzed, and an error elimination (EE) method of the machined feature is formulated. A case study is given to verify the EE method. Recommended by Prof. XIONG YouLun, Member of Editorial Committee of Science in China, Series E: Technological Sciences Supported by the National Natural Science Foundation of China (Grant Nos. 50475141, 50436010), the “973” Research Foundation of China (Grant No. 2005CB724103) and the Program for New Century Excellent Talents in University (Grant No. NCET-05-0651)     

提高滚轮法测量大直径精度的研究

滚轮法用于大型工件的直径测量时,由于滚轮和被测工件之间产生的滑失现象造成测量误差较大。在采用空气轴承,减小滚轮轴摩擦力,调整微调机构使滚轮轴与工件轴平行的正确方法之后,滑失现象减小,测量精度有所提高。同时还详细介绍了数据采集系统的硬件和软件。