薄壁件加工变形误差预估及补偿的集成

针对薄壁件数控加工过程中产生的力致变形误差,提出了一种将变形误差预测与误差补偿进行集成的方法。在提出高效的误差计算迭代算法基础上,采用APDL的方式开发了集迭代计算、刀具走刀、材料去除于一体的误差动态仿真程序,实现全过程加工误差的自动计算。借助UG二次开发工具UG/Open开发的应用程序实现了UG和ANSYS之间的数据通信,根据预测变形误差自动修正CAD模型,继而利用UG CAM生成考虑误差补偿因素的加工代码。研究了涉及误差离线预测及补偿的集成方法的多个关键技术。算例表明：误差预测值逼近实验值,精度可靠;集成软件能够自动生成误差补偿的加工代码,实现了误差离线预测和补偿全过程的CAD/CAE/CAM集成,集成程度高。     

Analysis of changes in coordinate measuring machines accuracy made by different nodes density in geometrical errors correction matrix

Advances in modern manufacturing techniques increase production efficiency but, at the same time, present new tasks and challenges for coordinate metrology and the manufacturers of Coordinate Measuring Machines (CMMs). The main goal of current research efforts is improving measurement accuracy. Seeing as many of the possible solutions regarding CMM construction had already been explored, there seems to be little left for improvement in that field. Further efforts at accuracy improvement rely mostly on using sophisticated mathematical algorithms designed to correct relevant errors. Many types of errors could be compensated using this approach, including: probe head errors, machine dynamics errors and, most importantly, machine geometrical errors. Almost all coordinate measuring machines produced nowadays are equipped with geometrical errors compensation matrix known as the CAA matrix (Computer Aided Accuracy).CAA matrices are based on a grid of reference points (nodes) in which certain values of the components of geometrical errors are determined experimentally. The error values between the nodes are estimated using simple interpolation methods. Theoretically, a higher density of reference points on the grid describing the CAA matrix should improve the accuracy of the machine utilizing the matrix. On the other hand, increasing the number of nodes simultaneously increases the amount of workload, time and money spent on constructing the CAA matrix. This paper presents a number of experiments aimed at creating CAA matrices with different number of matrix nodes using the LaserTracer system. The relations between maximum permissible errors obtained on a machine using matrices with different densities of nodes are also discussed. Additionally, the authors attempt to tackle the question of determining the most optimal density of nodes with regards to the ratio of time spent on matrix creation and the effect on accuracy.     

一种改进的动态数据校正离群值检测法

Data reconciliation technology can decrease the level of corruption of process data due to measurement noise, but the presence of outliers caused by process peaks or unmeasured disturbances will smear the reconciled results. Based on the analysis of limitation of conventional outlier detection algorithms, a modified outlier detection method in dynamic data reconciliation （DDR） is proposed in this paper. In the modified method, the outliers of each variable are distinguished individually and the weight is modified accordingly. Therefore, the modified method can use more information of normal data, and can efficiently decrease the effect of outliers. Simulation of a continuous stirred tank reactor （CSTR） process verifies the effectiveness of the proposed algorithm.     

光学非球面最佳参考圆的确定及其应用

应用干涉法测非球面,必须测量参考球面的曲率半径才能得到非球面的面形,因此需要精密的测长机构.本文介绍一种在一维测量时,用数学方法确定非球面最佳参考圆的参数,进而由干涉图求得非球面面形或面形误差的新方法,从而可省去测长机构.所提出的微扰动阻尼牛顿迭代法求非线性最小二乘解,经实践证明,有很好的迭代效果.     

RV减速器柔性因素对动态传动误差影响分析

为研究RV减速器柔性因素对传动精度的影响,以BX40E减速器为研究对象,综合考虑支承弹性变形及齿轮接触弹性变形对系统动态传动精度的影响,建立多自由度RV减速器动力学模型,提取系统的动态响应;探究变载、变速条件下各级传动接触及支承变形对动态传动误差的贡献量,量化分析BX40E减速器传动误差对各柔性因素的灵敏度。结果表明：动态传动误差随负载增加而增加,输出转速平稳性随负载和转速增加而下降;二级传动的接触变形对减速器传动误差贡献最大,柔性支承贡献次之;传动误差对“摆线齿轮-曲拐”处及“行星架-曲柄轴”处支承刚度的敏感度高于其他支承处,对二级齿轮接触刚度的敏感度高于一级传动。     

再制造双圆弧齿轮单齿切削机床设计

目前抽油机减速器双圆弧齿轮使用一段时间后会出现单个齿破损或多个齿间隔破损的情况,现有的修复方法效率低。针对这种情况,提出设计一种对修复后的再制造双圆弧齿轮进行再加工的切削机床,验证再制造双圆弧齿轮单齿加工的可行性。结合再制造双圆弧齿轮单齿展成加工理论,对单齿加工机床的刀具运动部件、齿向螺旋进给部件、齿形展成进给部件以及工件运动部件进行设计,最终得到满足加工要求的再制造双圆弧齿轮单齿切削机床。分析再制造双圆弧齿轮单齿加工的误差后,提出一种减小再制造双圆弧齿轮轴向齿距误差的方法。     

微分代数方程的一类并行算法

本文提出求解微分代数方程的一类并行算法,进行误差估计。对于一个模型问题进行稳定性分析,画出稳定区域。计算实例表明算法是有效的。     

基于HNC-8数控系统的机床热误差补偿方法

热误差在机床总误差源中占了极大比重,研究热误差补偿方法对于提高机床加工精度具有十分重要的意义。基于HNC-8(华中8型)数控系统的开放性特性,根据机床热误差的补偿原理,分析热误差补偿值的计算方法,并据此算法开发了集成于HNC-8数控系统的热误差补偿模块,最后结合实例,验证了补偿方法的有效性。     

外部转矩干扰的非完整移动机器人轨迹追踪控制研究

针对外部转矩干扰的非完整机器人运动不稳定、轨迹追踪控制精度较低等问题,提出了无源控制理论的控制方法。构造了非完整移动机器人的动力学模型,介绍了机器人空间运动控制的基本形式。采用无源控制方法设计了机器人末端执行器,使用李雅普诺夫综合法对无源控制闭环系统的稳定性和追踪误差的渐近收敛性进行了证明。结合具体实例,通过Matlab软件对外部转矩干扰的非完整移动机器人运动追踪轨迹和输出转矩进行仿真,并且与PI控制方法形成对比。仿真结果显示,无源控制方法的实际轨迹朝理论轨迹收敛,轨迹追踪误差较小,输出转矩波动小。无源控制方法可以避免外部转矩干扰的非完整机器人运动不稳定,提高轨迹追踪精度。     

基于三坐标测量机的非圆齿轮误差测量

为了提高非圆齿轮的测量精度和效率,提出应用三坐标测量机进行测量的思想。从制造工艺上根据非圆齿轮有别于圆齿轮的特点,提出适用于非圆齿轮的误差项目。通过类比圆柱齿轮精度指标公差的计算方法,找到非圆齿轮精度指标公差的计算方法。选取合适的测头、对测量路径进行规划、采用三坐标测量机实现对非圆齿轮的逐齿扫描测量,以获得非圆齿轮的齿廓数据值。在此基础上,对数据值进行曲线拟合和计算,从而得出非圆齿轮的误差。