A Novel Settling Controller for Dual-Stage Servo Systems

Dual-stage control is the most obvious step for the improvement of hard-disk drive servo systems, and it will most likely be used to support recording densities higher than 1 Tb/in². In this paper, we discuss the unique characteristics of settling the controller for dual-stage servo systems. A feedforward settling controller is designed to shape the position error signal profile before it is fed into the input of the track following controllers. Initial position and velocity causing transient errors are compensated through the designed feedforward controller for smooth and fast settling. The proposed method is convenient and suitable for real implementation. The simulation and experimental results are presented to demonstrate the design and effectiveness of the method.