Patent ID: 6859340

Claim:
A method for moving a read/write head across a surface of a rotating data storage disc in a disc drive, the read/write head being attached to an actuator arm and flying in close proximity to the surface of the data storage disc, the method comprising steps of: (a) retracting the read/write head from a first location on the surface of the data storage disc toward a second location; (b) measuring a retract velocity at which the read/write head is moving toward the second location; (c) comparing the retract velocity to a desired retract velocity; (d) if the retract velocity is less than the desired retract velocity, accelerating the read/write head toward the second location; (e) if the retract velocity is greater than the desired retract velocity, decelerating the read/write head toward the second location; and (f) repeating the measuring step (b), the comparing step (c), the accelerating step (d) and the decelerating step (e) to maintain the retract velocity about the desired retract velocity, wherein the first location is a data region on the surface of the data storage disc and the second location is a non-data location on or in close proximity to the surface of the data storage disc and wherein the retracting step (a) comprises steps of: (a)(i) rectifying current resulting from a rotational inertia in the data storage disc generated as the data storage disc continues spinning following a disc drive power-down to produce a control current having one or more periods of non-zero magnitude phases, each non-zero magnitude phase being followed in time by a zero magnitude phase; and (a)(ii) applying the control current to a coil of a voice coil motor operably connected to the actuator arm to produce movement of the actuator arm.