莫尔条纹光电信号细分误差的实时补偿  

Real-time compensation of subdivision error for Moire fringe photoelectric signal

作　　者：高旭[1,2] 李俊峰[3] 张淑梅[1] 万秋华[1] 

机构地区：[1]中国科学院长春光学精密机械与物理研究所,吉林长春130033 [2]中国科学院大学,北京100049 [3]中国科学院长春光学精密机械与物理研究所光学系统先进制造技术重点实验室,吉林长春130033

出　　处：《红外与激光工程》2013年第11期3013-3018,共6页Infrared and Laser Engineering

基　　金：中国科学院知识创新工程领域前沿项目

摘　　要：为了保证高精度光电轴角编码器在恶劣工作条件下的细分精度，设计了基于高分辨率数字电位计的实时补偿处理系统。依据莫尔条纹光电信号的数学模型，说明了由信号等幅性偏差和直流电平漂移引起的细分误差的空间分布特征，并得出误差规律及计算公式，从编码器的光机装调、码盘均匀性、光敏元件调试等制作环节出发，指出了编码器光电信号细分误差的根本特性；受高精度光电编码器分辨力的约束，从编码器光敏元件输出莫尔条纹信号的形式出发，构建了分辨率为0.1Ω的数字电位计查找表；并设计了实时补偿的关键算法。以23位光电编码器为实验对象，在-40~60℃条件下对补偿处理系统测试，实验结果表明：直流漂移≤1.2%，等幅性≤2%，且自动补偿时间约为3 s，满足编码器分辨力（0.154＂）和工作实时性的要求。该方法可实际应用于编码器系统，能够提高编码器的环境适应性和测角可靠性。In order to ensure the interpolation precision of the high precision photoelectric rotary encoder in the harsh working conditions, the real-time compensation processing system based on digital potentiometer was designed. On the basis of Moire fringe photoelectric signal mathematical model, the spatial distribution of the subdivision error due to signal amplitude deviation and DC drift was revealed. Error discipline and calculation formula was obtained. From several production aspects, such as encoder opto-mechanical alignment, uniformity of the code disk and photosensitive element debugging,fundamental characteristic of the encoder photoelectric signal subdivision error was pointed out. The resolution of high precision photoelectric encoder was constrained. From the Moire fringe signal form outputted by encoder photosensitive element, digital potentiometer look-up table with 0.1Ω resolution was constructed and key algorithm of real-time compensation was designed. A 23 bit encoder was selected as the experimental object and the compensation processing system was tested at -40-60℃. The experimental results showed that the DC drift was less than 1.2% and amplitude difference was less than 2% and the automatic compensation time was about 3 s. It can meet the encoder resolution （0.154＂） and real-time requirements. The method can be applied in the encoder system and improve the environmental adaptability and angle measurement reliability.

关 键 词：高精度光电编码器 数字电位计 细分误差 实时补偿 

分 类 号：TP394.1[自动化与计算机技术—计算机应用技术]