A method to calculate displacements as End of Line Calibration for AMR-based angular sensors

Precise angular measurement is important for many applications in the automotive domain such as electric power steering or throttle/pedal systems. The accuracy of such an angle sensing system essentially depends on mounting tolerances. In this paper we show a methodology, which is able to detect a displacement between sensor and magnet. We compute the magnet position exploiting the minima and maxima of the magnetic field which is sampled by the AMR sensors. By using measurements of a sensor array consisting of anisotropic magneto-resistive (AMR) angular sensors an End of Line Calibration can be done. From this follows relaxed mounting tolerances while the accuracy is preserved. Thus, the presented technique lead to a significant improved mechanical flexibility and lower production costs.