Patent ID: 7688019

Claim:
A method for compensating for a position error of a step motor, comprising: sequentially inputting a predetermined number of a pulse as a rotator position command to a step motor driver; driving the step motor in a micro step method based on the rotator position command and a predetermined current command table; detecting an actual position of a rotator of the step motor while the step motor is being driven; calculating a position error by comparing the rotator position command and the detected actual position of the rotator; and compensating for the predetermined current command table based on the calculated position error, wherein the compensated current command table is obtained by Equation: f _ ⁡ [ k ] = f ⁡ [ k ] - f ⁡ [ k ] - f ⁡ [ k - 1 ] θ ⁡ [ k ] - θ ⁡ [ k - 1 ] ⁢ Δθ ⁡ [ k ] , k = 1 , 2 , … ⁢ , M g _ ⁡ [ k ] = g ⁡ [ k ] - g ⁡ [ k ] - g ⁡ [ k - 1 ] θ ⁡ [ k ] - θ ⁡ [ k - 1 ] ⁢ Δθ ⁡ [ k ] , k = 1 , 2 , … ⁢ , M where f [k] and g [k] are current command data which are included in the compensated current command table, f[k] and g[k] are current command data which are included in the current command table before the compensation, θ[k] is the actual position of the rotator, Δθ[k] is the calculated position error, and M is the number of micro steps corresponding to one cycle of an electrical angle of the step motor.