Design of single-pole magnetic encoder based on calibration

Compared with an optical, the structure of a magnetic rotary encoder is very simple and not affected in dust and mist condition. But its resolution and accuracy are low and difficult to be improved, so the application of the magnetic rotary encoder is limited. Aiming at improving the resolution and accuracy of the single-pole encoder, a new signal-processing method based on calibration is proposed. A high resolution optical encoder was used as the calibration basis. Signal was processed using FPGA (Field Programmable Gate Array) and the angle was got through the table look-up in different region according to the 2-phase voltage. By using this method, a magnetic rotary encoder was made, and its resolution is up to 31757 p/r and the accuracy can achieve 12 bits (4096 lines).