基于FPGA的电容式编码器数据采集系统设计与实现

Design and Implementation of Capacitive Encoder's DAQ Based on FPGA

为了精确地获取电容式编码器输出信号中所携带的位置信息,文章设计了一套基于现场可编程门阵列(FPGA)的电容式编码器数据采集系统;文中介绍了带通滤波器、同步正交解调、低通滤波器和Cordic等系统模块,并详细分析了系统的稳定性和误差;实验结果表明,在转速度为800rpm时,角度分辨率可达到0.192度,在一个周期内最大误差0.002 8度,平均误差0.000 8度,静止抖动0.007 26度,统能够实时的获取转子的位置信息,同时具有较好的精度和稳定性。

In order to accurately obtain the position information from the output signal,this paper proposed a capacitive encoder＇s data acquisition system based on FPGA.Algorithm of band pass filter,synchronous quadrature demodulator,low pass filter,and Cordic have been adopted in the design.And we make a detail discussion about the system stability and error.The results show：as rotational speed is 800rpm,resolution is 0.192 degree and the mean error is 0.0008 degree.The system not only obtains the position information of rotor in a real time,but also has a good resolution and accuracy.