Abstract
Wide frequency band is needed for HDD actuator mechanical characteristics to position heads precisely on tracks. In this paper, a new type actuator for HDD is proposed which is based on the new concept called a mode control method. The mode control system cancels a major resonant mode on the transfer function of a servo system and makes the servo band wider. The new type actuator has two driving mechanisms. One is a conventional driving coil and another is a PZT actuator which operates in parallel with the driving coil. The two actuators drive different major mode shapes that have same resonant frequencies and phases but different gains. By driving the PZT at an inverse gain of the coil, the major peak of the head actuator can be decreased and a dominant peak of the head actuator moves to a higher mode. Simulation and experimental results agreed well and showed good performance.
