Control of a micro-actuator for hard disk drives using self-sensing actuator

Abstract

This paper describes vibration control and position control of a micro-actuator for hard disk drives using self-sensing actuator. A stabilizing feedback control low is designed by using Lyapunov's direct method. The feedback control law depends only on the time derivative of tip slope in the micro-actuator. The self-sensing actuation using the electrical RC bridge circuit can measure strain rate in the micro-actuator. This sensing signals correspond to the time rate of tip slope in the micro-actuator. The feedback controller derived from Lyapunov's direct method can realize by using the self-sensing signal. A two-degree-of-freedom control system consists of a feedforward and the feedback controller. The feedforward controller is designed by using inverse dynamic system, while the stabilized feedback controller is designed by Lyapunov's direct method. Numerical simulation and experimental results confirm the feasibility of the proposed control system.