基于DSP和FPGA提高增量式光电编码器精度的研究

Research on the Precision Improvement of Incremental Optical Encoder Based on FPGA and DSP

研究一种基于数字信号处理器(DSP)和现场可编程门阵列(FPGA)增量式光电编码器精度提高的方法。首先分别对低精度(500puls/r)和高精度(2 500puls/r)的增量式光电编码器的原始输出信号进行滤波和电平转换处理,然后将低精度光电编码器和DSP输出的采样脉冲信号输入到FP-GA中,通过数字时间转换(TDC)方法测出2个脉冲信号之间的时间差值(误差为0.67ns),将时间差值利用数据总线实时送入到DSP中进行算法处理,得出采样处的位置,并与输入到DSP中的高精度光电编码器位置进行比较,分析表明精度提高了5倍。

To research on the method of the accuracy improvement of incremental optical encoder based on digital signal processor（DSP） and field programmable logic array（FPGA）.Firstly,the output signals of low-precision（500 puls/r） and high-precision（2 500 puls/r） the incremental optical encoder were filtered and level shifted respectively,then the signal of low accuracy incremental optical encoder and DSP＇s output sampling pulse were input to FPGA,the time difference（error of 0.67ns） between the two pulses was calculated by time-to-digital converter（TDC）,the time difference was input to the DSP by data bus real-timely,the position of sample was obtained by algorithm processing which compare with DSP＇s high-precision optical encoder position,the analysis showed that its accuracy increases five-fold.