Patent ID: 8091003

Claim:
A position detection error correcting method comprising: a first step of storing beforehand in a first storage means a correction parameter set specifying one of a plurality of correction functions each of which express detection error correction values of a position detector, the correction functions corresponding to a series of periodic functions; a second step of reading out said correction parameter set from said first storage means, calculating the detection error correction values corresponding to detected positions and storing the calculated detection error correction values in a second storage means; and a third step of reading out the detection error correction values corresponding to detected position values output from said position detector from said second storage means and calculating corrected detected position values corrected for errors in said detected positions; wherein, expressing said detected positions by θ, said correction function C(θ) is expressed by equation (1) below in which a periodic function G(θ) is a power function of θ: [ Mathematical ⁢ ⁢ Expression ⁢ ⁢ 1 ] C ⁡ ( θ ) = ∑ n ⁢ { A n · G ⁡ ( n ⁢ ⁢ θ + B n ) } + D ( Eq . ⁢ 1 ) where n: order An: amplitude component of the correction parameter set; Bn: phase component of the correction parameter set; and D: offset of the correction parameter set.