绝对式位移测量标尺的定位算法研究
时间:2019-12-08 15:23 来源:毕业论文 作者:毕业论文 点击:次
| 摘要图像式编码器作为一种常用的位移测量仪器，具有结构简单，测量精确度高的优点。其核心为位移标尺，其中单码道标尺具有易于小型化，智能化的特点。本论文基于绝对位移码定位的一般原理，利用 MATLAB软件对一种单码道直线位移连续码的定位算法进行仿真，首先根据位移连续码的编码原理生成标尺的条码图案，再根据光学成像和 CCD 图像传感器的工作原理，模拟生成 CCD 采集到标尺条码片段的输出（像素灰度值）信号，然后采用二阶导数过零法确定条码边缘位置确定目标码字，并通过与原码进行比较得到目标码字的序号，从而得到位置粗读数，进而确定 CCD 中心像素位置（测量基准线）与粗读位置间的距离得到精读数，二者相结合得到位置量。仿真算法的最终结果显示了其的准确性与稳定性，为基于该码的绝对式位移编码器的工程实现提供了理论基础。42535 毕业论文关键词 位移连续码；CCD 图像传感器；二阶导数过零法 Title A research on algorithm of absolute positionmeasuring scale Abstract As a widely-used position measuring instrument, the encoders have the advantagessuch as simple structure and high measuring accuracy. Its core part is the positionmeasuring scale. As a developing tendency, the single channel code scale can helpto realize miniaturization and intelligentialization. In this thesis, thepositioning algorithm of a absolute linear continuous displacement code issimulated by using MATLAB based on the common theory of absolute displacement code.Fist the bar code pattern is generated according to the coding theory of this code,then the CCD output signal ( Grey levels of pixels)is produced based on the opticalimaging theory and CCD working principle. The 2-order derivative zero-crossingmethod of edge detecting is applied to get the code word which is then comparedwith the source code to get the coarse reading of the position, Then the fine readingcan be defined by calculation the distance between the central pixel of CCD(themeasuring reference line)and the coarse reading position. Thus the final positionresult can be obtained. The comparing results of calculated position with the idealposition prove that the algorithm is correct, which can provide a theoretical basisfor engineering realization of this position code. Keywords continuous displacement code; CCD; second derivative zero crossingmethod 目 次 1 引言1 1.2绝对式编码器编码方式1 1.3图像式编码器介绍2 1.4论文研究内容2 2 绝对位移码的编解码原理3 2.1绝对位移码定位的一般原理3 2.2 位移连续码的编解码原理4 3 图像传感器模拟成像信号6 3.1条码模型6 3.2光学系统点扩散函数6 4 边缘检测10 4.1 二阶导数过零法寻找边缘的方法原理10 4.2CCD 输出位移码信号的边缘检测10 5 位置信息的获取 12 5.1 得到码字12 5.2 粗读数的获取12 5.3 精度数的获取13 结论 15 致谢 16
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