Development of Higher Accuracy Magnetic Absolute Encoder

Abstract

The purpose of this study is to develop an absolute track recording method to develop a higher accuracy magnetic absolute encoder. Shortening the magnetic pole distance is effective to achieve higher accuracy, but the absolute position misdetection due to attenuation and interference of the magnetic signal on the absolute track decrease the accuracy. Therefore, a magnetic pole array and its decoding method are developed to solve the problems of magnetic signal attenuation and interference by increasing the magnetic pole spacing without allowing three or more identical magnetic poles in succession. When the magnetic pole distance is shortened, the magnetic signal of the absolute track of the developed method detects the absolute position with a larger sensor gap than the existing method. At the magnetic pole distance realized by the developed method, interpolation errors are reduced, confirming the high accuracy of the magnetic absolute encoder.