Patent ID: 8346435

Claim:
An electric power steering control device, comprising: steering torque detector for detecting a steering torque applied by a driver from a relative angle of a torsion bar; a torque controller for computing an assist torque current for assisting the steering torque based on a steering torque signal detected by the steering torque detector; a motor for generating a torque for assisting the steering torque; a rotation speed estimator for estimating a rotation speed of the motor; and a damping controller for computing a damping current to be added to the assist torque current by using an estimated value of the estimated rotation speed of the motor, wherein the rotation speed estimator includes: a steering component removing part for steering torque, for removing a component due to steering from an output of the steering torque detector; a rotation angle corresponding value computing part for multiplying an output of the steering component removing part for steering torque by an inverse number of a rigidity of the torsion bar and −1 to compute a value corresponding to a rotation angle; and a rotation angle differentiator for differentiating an output of the rotation angle corresponding value computing part to compute a value corresponding to a rotation angular velocity.