A Rotary Encoder based on Magneto-Optical Storage Method

摘要

We propose a new kind of rotary encoder based on a magneto-optical storage method. By using this method, a rotary encoder with small size, high precision and response can be realized. High precision can be achieved with the ability for re-recording by using the transfer recording with error correction method. The method is as follows. Firstly, an initial recording is made directly from the reference encoder and angle position errors of MO encoder are measured. Correcting values to cancel errors are calculated based on Fourier analysis. Finally, MO encoder is re-recorded with the correcting values after erasing. The following issues are described: (1) A device for recording, playback and evaluation of MO encoder has been developed. (2) MO encoder made for trial purposes was recorded by 2250 p/r (pulses/revolution) directly from the referential encoder. Accuracy of about 2.5" and reproducibility of 0.079" were achieved. (3) As a result of experiments for transfer recording with error correction, an accuracy of 1.3" for 2250 p/r and 1.7" for 9000 p/r was achieved.