Head Actuator Assembly Vibration Compensation of Hard Disk Servos

With the aim to improve the servo performance of hard disk drives, this paper proposed a multi-sensing and multi-rate controller to compensate the head actuator assembly vibration. To perfectly measure the most important resonance modes of the voice coil motor (VCM) and suspension, a cheap but effective PZT sensor is attached to the arm of the actuator. A robust controller is developed with the μ-synthesis tool by considering system uncertainties and disturbances. To achieve the multi-rate control, an H∞closed-loop performance based discretization technique is proposed to obtain a discrete-time domain controller with the best approximation to the continue-time system. Simulation results are shown to verify the effectiveness of the proposed control scheme.