Method and apparatus of dual stage servo control with dual control paths and decoupling feedback for track following in a hard disk drive

A method comprising the step of

• controlling a magnetic head to follow a track on a rotating disk surface in a hard disk drive, comprising the steps:
• a micro-actuator control (250) creating a micro-actuator control signal (252) based upon a micro-actuator direction (204) to stimulate a micro-actuator (310);
• wherein said magnetic head is positioned near said track by an effect of said micro-actuator and by an effect of a voice coil motor (300), both included said hard disk drive;
• a voice coil motor control (220) creating a voice coil control signal (222) based upon a voice coil motor direction (212);
• amplifying (240) said voice coil control signal based upon a tuning gain (244) to create a tuned voice coil control signal (242) stimulating said voice coil motor (300);
• removing (200) a Positional Error Signal (PES) from a track following command (202) to create said micro-actuator direction (204);
• wherein said PES signal is based upon said effect of said voice coil motor and based upon said effect of said micro-actuator in positioning said magnetic head near said track;
• decoupling feedback filtering (260) said micro-actuator control signal to create a decoupling feedback signal (262);
• and
• removing (210) said PES and said decoupling feedback signal from said track following command to create said voice coil motor direction.