关节式坐标测量机圆编码器误差与空间误差研究

发布时间：2018-12-23 12:06

【摘要】：关节式坐标测量机为多级串联式极坐标测量系统,其测量误差会逐级传递、积累放大,使得其精度相比于正交三坐标测量机还有较大差距,这制约了其在实际工程中的应用。关节式坐标测量机在不同测量姿态下,由六个关节上安装的圆光栅编码器测得的关节角度组合是不同的,而圆编码器在各个角度上所存在的圆编码器误差也是不同的,因而在空间中测量不同点或固定一点不同姿态时由圆编码器误差所产生的测量误差也会不同,若能找出测量误差较小的区域(最佳测量区),测量时将被测件放置在最佳测量区中,显然能够提高测量时的测量精度。然而,关节式坐标测量机误差源较多,单独分析圆编码器误差对测量机测量空间误差分布较为困难,本论文基于虚拟样机技术建立了关节式坐标测量机虚拟样机模型,并在该模型基础下分析了圆编码器误差与空间测量误差分布的关系,为后续研究打下了基础,主要研究内容如下：1、测出圆编码器误差,给出其数学表达式,并给出图像显示；2、应用虚拟样机技术建立关节式坐标测量机的虚拟样机模型,该模型消除了绝大部分误差源,使能够单独分析由圆编码器误差而引起的测量误差；3、提出了一种用采集一个面上的点替代整个测量空间的点的方法,该方法解决了在空间采集大量均匀点时存在的工作量大及复杂度高的问题；4、基于MATLAB软件,运用向量化编程思想建立起分析由圆编码器误差而产生的空间误差分布的平台,对空间任意固定点、一个平面以及整个空间的由圆编码器误差而产生的测量误差进行仿真分析,找出最佳测量区；并分析改变装配测量机时安装圆编码器的初始安装角度,达到可测区域内测量误差整体减小的目的。
[Abstract]:The joint coordinate measuring machine (CMM) is a multistage series polar coordinate measuring system, and its measuring error will be transmitted step by step and accumulated and amplified, which makes the precision of the CMM worse than that of the orthogonal CMM, which restricts its application in practical engineering. The joint angle combination measured by the circular grating encoder installed on the six joints is different for the joint coordinate measuring machine, and the error of the circular encoder in each angle is also different, under the different measuring attitude, the joint angle combination is different by using the circular grating encoder installed on the six joints, and the error of the circular encoder is also different in each angle. Therefore, when measuring different points or different attitude at a fixed point in space, the measurement error caused by the error of the circular encoder will also be different. If we can find out the area where the measurement error is small (the best measurement area), It is obvious that the precision of measurement can be improved by placing the measured parts in the optimum measuring area. However, there are many error sources of joint coordinate measuring machine (CMM), so it is difficult to analyze the error of circular encoder on the spatial error distribution of CMM alone. In this paper, a virtual prototype model of CMM is established based on virtual prototyping technology. On the basis of this model, the relationship between the error of circular encoder and the distribution of spatial measurement error is analyzed, which lays a foundation for further research. The main contents are as follows: 1. The error of circular encoder is measured and its mathematical expression is given. The image display is given. 2. The virtual prototype model of joint coordinate measuring machine (CMM) is established by using virtual prototyping technology. This model eliminates most of the error sources and makes it possible to analyze the measurement error caused by circular encoder error separately. 3. A method of replacing the whole measuring space with collecting points on one surface is proposed. This method solves the problem of large workload and high complexity when collecting a large number of uniform points in space. 4. Based on MATLAB software, a platform for analyzing spatial error distribution caused by circular encoder error is established by using vectorization programming thought. The measurement error caused by the circular encoder error in a plane and the whole space is simulated and analyzed to find out the best measurement area. At the same time, the initial installation angle of the circular encoder installed in the assembly measuring machine is analyzed to reduce the measurement error in the measurable area as a whole.
【学位授予单位】：合肥工业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TH721

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