Patent ID: 8949068
Filing Date: 2015-02-03
Classification: G01D

Abstract:
1. A rotation angle detection device comprising: a circuit part having plural sensor element groups for sensing a rotating magnetic field from a detection target, in which impedance of each of sensor elements in the sensor element groups changes according to a rotation angle of the detection target; an output signal acquisition part for acquiring, from each of plural sensor element groups, an output signal; a rotation angle calculation part for calculating a rotation angle of the detection target based on the output signal acquired by the output signal acquisition part; a mean value fixation check part for checking whether a mean value fixation abnormality is caused based on a first value that is calculated by using the output signal acquired by the output signal acquisition part, the mean value fixation abnormality being determined by continuously outputting a mean value of a maximum value and a minimum value of an amplitude of the output signals that are used for the calculation of the first value in a normal condition; and an abnormal signal identification part for identifying the output signal which has the mean value fixation abnormality based on a second value, the second value calculated based on the output signal acquired by the output signal acquisition part; wherein the mean value fixation check part calculates, as the second value, one of the output signal itself and an output value equivalent value that is derived by adding or subtracting a predetermined value to or from the output value, respectively; and the abnormal signal identification part determines that one of the output signal and the output signal corresponding to the output signal equivalent value has the mean value fixation abnormality if one of the output signal and the output signal equivalent value is within a predetermined range.