A novel AMR based angle sensor with reduced harmonic errors for automotive applications

The paper presents the development of a novel anisotropic magnetoresistive sensor for measurement of angle in the interval 0° to 180°. A sensor is comprised of two Wheatstone bridges arranged at 45° to each other. A unique design is proposed wherein each resistive element of the Wheatstone bridge was formed with strips of varying widths. It results in a substantial reduction in harmonics errors due to the dispersion of the shape anisotropy field values within each element. The reduced harmonic errors also lead to a drastic reduction of hysteresis error (60%) and offer better accuracy with a signal amplitude of 18 mV/V even in weak fields of ≤80 G. Further, the sensor was employed in the development of a pedal position sensor. The preliminary results of the development are presented, indicating the usability for industrial and automotive applications