Development of the Noncontact Steering Angle Sensor using a Giant Magnetoresistive Element

Recently, to advance endurance and reliability, automotive position sensors have been replaced by noncontact sensors. We successfully developed the steering angle sensor (SAS) using a GMR element [9]. This GMR element has a larger magnetoresistance ratio and higher thermo stability than a Hall element and an AMR element. Our SAS consists of a magnet, an electromagneto conversion device (ALSIR) and a signal processing circuit (ASIC). ALSIR outputs high accuracy and repeatability sine and cosine waves. ASIC calculates the arctangent of those signals, and converts the magnet rotation angle of 360 degree into linear signals with 14 bit resolution.