Abstract
This paper discussed the development and validation of a new rotary magnetic encoder for measurement of spindle's axial displacements. The novelty of this work is on the design of permanent magnets as the magnetizing source to produce alternative magnetic polarities on ferromagnetic material electroplated on disk/ring-like flange that is attached to the targeted spindle shaft. Through mechatronics integration and numerical finite element parameter studies, the optimal combination of the magnetizer design parameters with consideration of the arrangement of magnetoresistive (MR) elements is reached to produce the novel encoding magnetic patterns for the axial displacement measurements. The effectiveness of the proposed method is further validated through calibrated experiments leading to the conclusion of reaching 10um accuracy performance in the measurement of the spindle's axial elongation.