Design and analysis of a magnetic off-axis rotary position sensing device

In the paper design and analysis of an off-axis absolute rotary position sensor setup is described that is intended to use in realizing accurate and reliable absolute angle measurement to be applied in precise control of electric (e.g. vehicle) drives. A solution of using magnetic position sensing elements in combination with two differently magnetized ferromagnetic rings is presented. By assuming a specific setup the algorithm of determining absolute position is given, as well by analyzing the measurement errors, a compensation scheme is elaborated. By using this scheme the linearity error of the sensor setup can significantly be reduced without applying any expensive equipment.