Characteristics of magnetic sensor with assembly errors in a rotary recording system

Abstract

A magnetic position sensing system consists of a magnetic rotary ring with polarities magnetized on its radial surface and a position sensor made of magnetoresistance. Two quadrature sinusoidal output signals from sensor are processed into position information for motion control application. Magnetoresistance varies with the angle between magnetization (M) of external field and flow current (I) inside the sensor patterns. Therefore, the assembly error either in sensor or rotary ring would cause distorted signal. The assembly error between sensor and the medium such as offset, pitch, roll, yaw error and eccentricity between scale and stage of motion centre of read head would be discussed in this paper. Experimental and analytical parameter studies were conducted in this paper to discuss the accuracy error and variation of output quadrature signal caused by assembly error. Through the parameter studies, the data under various conditions can then be used to serve as a baseline.