Method of estimating the stroke sensitivity of micro-actuator coupled with slider and its read-write head. Micro-actuator stimulus signal used to drive micro-actuator, inducing noise into lateral positioning of read-write head near track by voice coil motor to create PES. Lateral position noise derived from Position Error Signal. Stroke sensitivity estimated from lateral position noise and micro-actuator stimulus signal. Apparatus supporting method estimating stroke sensitivity: servo controller, embedded circuit including servo-controller, and hard disk drive may include servo-controller and/or embedded circuit. Method making servo-controller, embedded circuit, and/or hard disk drive. Servo-controller, embedded circuit, and hard disk drive are products of these processes.