绝对式光栅传感器关键技术的研究

发布时间：2018-05-23 18:54

本文选题：绝对式光栅尺 + 细分技术　；参考：《吉林大学》2017年硕士论文

【摘要】：光栅测量技术在精密测量领域占据着重要地位,相比激光测量,光栅常数受环境影响小,具有较强的抗干扰能力,因此普遍应用于数控机床。近年来我国在光栅测量领域取得了长足的进步,但是仍然落后于德国和日本等发达国家,目前国内主要生产增量式光栅尺,无法达到高效定位的目的。大部分超精密仪器采用的高精度光栅尺仍然依靠进口,特别是绝对式光栅尺高端技术仍被国外垄断。因此开展具有高精度高分辨率的绝对式光栅尺关键技术的研究,分析阻碍分辨率和测量精度提升的因素并找到解决方案具有重要意义。本文就绝对式光栅尺中的细分技术、误差补偿算法做了专门的研究。设计了用于光栅尺精度检测的气浮式精度检测平台,通过实验验证了各项技术的精度和可靠性。目前国内公开的对于光栅的细分技术的研究大部分是采用经典细分技术中的幅值分割法,将测量得到的信号拟合成正切线中[0,45°]这一段,然后对其进行细分,在运用MATLAB对其进行仿真时发现这一段是接近一条直线,但是对于高倍细分误差就变得明显。因此新型细分技术不再是对其进行拟合,而是直接在原曲线上取点进行等距离细分,对采集到的曲线进行滤波,修正处理后将曲线上的点送入查找表确定位置。优点在于每一个位置代表的都是真实值,细分值均匀可靠,经过测试能够达到10nm的分辨率,精度等级达到±3um。绝对式光栅尺实时读取绝对位置其绝对码道的编解码技术起到了关键作用,编码方式的不同使得光栅传感器在性能和效率上存在差异。现代工业产品向集成化,小型化方向发展,因此我们采用复合多位元m序列伪随机码为基础的编码方式,优点是绝对码的码道只有一条,结构紧凑,编码的周期长且可以复制,便于加工使用。在机误差补偿技术是根据安装环境的不同将每把光栅尺用双频激光干涉仪检测出自身需补偿的数据,保存到读数头存储器,实际应用时调用存储器中的值进行误差补偿。减少了由于安装环境和装配精度等外界因素造成的误差。此外光栅尺本身的测量误差是采用一种新的算法将由于存在相位差产生的椭圆型的李萨育图形转换为标准的李萨育圆,这样便可以直接查询标准的查找表。为了检验本文研究的细分技术的高精度高稳定性以及误差补偿算法的有效性,我们设计了一台采用空气轴承的精度检测平台,并与常用的丝杠导轨的检测平台进行了实验对比。选取同一把光栅尺的相同位置,每次前进两个分辨率的距离,记录得到的数值,对每一个数组的标准差进行对比。通过实验验证,空气轴承的精度检测平台摩擦阻力小,抗振能力强,具有更高的检测稳定性。在对新型光栅尺的验证部分,首先通过基于空气轴承的精度检测平台对其进行精度检测,通过对实验数据进行分析:经过误差补偿精度能够达到±3um,同时对另一个重要参数重复度进行测试,对光栅尺正反两行程多点进行检测,通过对数据的分析,重复度误差同样小于±3um,稳定性非常好。
[Abstract]:Grating measurement technology occupies an important position in the field of precision measurement. Compared with the laser measurement, the grating constant is less affected by the environment and has strong anti-interference ability. Therefore, it is widely used in CNC machine tools. In recent years, China has made great progress in the field of grating measurement, but still lagging behind Germany and Japan and other developed countries. The main production of the incremental grating ruler can not achieve the purpose of high efficiency positioning. Most of the high-precision grating rulers used in ultra precision instruments are still dependent on the import, especially the high end technology of the absolute grating ruler is still monopolized abroad. Therefore, the research on the key technology of the absolute grating ruler with high precision and high resolution is carried out and the resolution of the resolution is analyzed. In this paper, the subdivision technology of the absolute grating size and the error compensation algorithm are studied in this paper. The air floatation precision testing platform for grating ruler precision detection is designed, and the accuracy and reliability of various technologies are verified by experiments. At present, it is open at home. Most of the research on the subdivision of the grating is the use of the amplitude segmentation method in the classical subdivision technology. The measured signal is proposed to synthesize the [0,45 degree section of the positive tangent line. Then it is subdivided. When the MATLAB is used to simulate it, it is found that this section is close to a straight line, but the high subdivision error becomes clear. Therefore, the new subdivision technique is no longer fit for it, but it takes the distance subdivision directly on the original curve, filters the collected curves, and then corrections the points on the curve to determine the position. The advantage is that each position represents the true value, the subdivision value is uniform and reliable, and the test can be carried out. In order to reach the resolution of 10nm, the precision grade reaches the absolute position of the absolute position of the 3um. absolute grating ruler. The coding and decoding technology plays a key role. The difference of the encoding mode makes the grating sensor difference in performance and efficiency. The modern industrial product develops to the integrated and miniaturized direction, so we use the composite The multi bit m sequence pseudorandom code is based on the coding method. It has the advantage that the code channel of the absolute code is only one piece, the structure is compact, the encoding period is long and can be copied, which is convenient for processing. The reading head memory is used to compensate the value of the memory in the actual application. It reduces the error caused by the external factors such as the installation environment and assembly precision. In addition, the measurement error of the grating ruler itself is a new algorithm that converts the elliptical type of plum breeding graphics from the existence of the phase difference to the standard Li Sa. In order to test the high precision and high stability of the subdivision technology and the validity of the error compensation algorithm, we designed a precision testing platform using air bearing, and compared the test platform with the common screw guide rail. The same position of the ruler, each time the distance of two resolutions forward, the value recorded, the standard deviation of each array is compared. Through the experiment, it is proved that the friction resistance of the air bearing detection platform is small, the anti vibration ability is strong, and the test stability is higher. The accuracy detection platform of the bearing is accurate. Through the analysis of the experimental data, the accuracy of the error compensation can reach to + 3um. At the same time, the repetition of another important parameter is tested, and the multiple point of the positive and negative two stroke of the grating ruler is detected. Through the analysis of the data, the repeatability error is also less than + 3um, and the stability is very stable. OK.
【学位授予单位】：吉林大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TP212;TG659

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