Patent ID: 7795834

Claim:
A servo motor controller to correct a position of a moving object connected with the servo motor through an elastic body based on a torque command value of the servo motor, the servo motor controller comprising: a rotating direction detecting unit to detect a rotating direction of the servo motor; a rotating angle computing unit to compute a rotating angle of the servo motor; a rotation resistance computing unit to compute rotation resistance on the servo motor side; and an elastic deformation error amount computing unit to compute a deformation error amount of the elastic body, wherein the controller corrects a position of the moving object by the steps of; detecting the reverse of the servo motor in the rotating direction detecting unit; computing rotation resistance in the rotation resistance computing unit based on a rotating angle of the reversed servo motor; and computing the elastic deformation error amount in the elastic deformation error amount computing unit based on the computed rotation resistance and the torque command value of the servo motor.