Patent ID: 7231313
Filing Date: 2007-06-12
Classification: G01D

Abstract:
1. A method of calculating a compensation value for an angle detecting sensor including a sensor unit that generates a rotating magnetic field in accordance with rotation of an object to be measured and that detects the rotating magnetic field to output a plurality of output signals in accordance with an input angle of the rotation; a signal converting section that converts the plurality of output signals into two signals having a predetermined phase difference; a signal adjusting section that adjusts offsets and gains of the two signals; an arithmetic operation section that calculates a rotation angle of the object from the two signals after the adjustment as an output angle before compensation; a memory section in which the compensation value used for compensating for a total error signal included in the output angle before compensation is written in advance; and a compensator that removes the compensation value from the total error signal included in the output angle before compensation to calculate an output angle of the object, the method comprising: generating the two signals having the predetermined phase difference from the plurality of output signals; calculating the rotation angle of the object from the two signals as the output angle before compensation; extracting a candidate signal having a minimiun residual energy in the signal after removal as the compensation value when a plurality of candidate signals having the same period but different amplitudes has been removed from the total error signal included in the output angle before compensation; subtracting the candidate signal from the total error signal; and outputting the generated output angle to an external device, the output angle of the object based on the subtracted total error signal.