CONSIDERATION FOR A HIGH-RESOLUTION OF MAGNETIC ROTARY ENCODER

The structure of a magnetic rotary encoder is very simple compared wit h an optical type and is not affected in dust and mist conditions, How ever, a magnetic rotary encoder with an upper limit of encoder resolut ion of 2000 pulses per revolution(ppr) per track has lower resolution compared with an optical encoder, In this paper, a high resolution mag netic rotary encoder with 4000 ppr per track resolution utilizing a mi nimum number of magneto-resistive elements has been developed by using a double interpolation method. A parameter analysis of the magnetizat ion and the detection processes for the main magneto-resistive output voltage using a finite element method is described.