Optimal track following control for hard disk drives

This paper presents an optimal track following control design procedure for hard disk drives (HDD) to reach higher track densities given the disturbance and noise model in the HDD and the actuator bandwidth limitation. The linear-quadratic Gaussian/loop-transfer recovery (LQG/LTR) technique is used to design a family of controllers that minimize the position error variance due to disturbance and measurement noise during track following. An optimal controller is obtained by selecting the LQG/LTR controller that achieves the minimal position error signal (PES) tracking errors given the open-loop limitation.