A high bandwidth piezoelectric suspension for high track density magnetic data storage devices

Maintaining the trend towards higher track densities and data rates in magnetic recording devices requires track following servo systems of increasing bandwidth for reliable storage and retrieval of data. The increase in bandwidth is limited by the presence of mechanical resonance modes and other nonlinearities in the voice coil motor (VCM) actuators. One approach to overcoming the problem is by using a dual-stage servo mechanism. In such a mechanism, a VCM is used asa primary stage while a microactuator is used as a secondary stage. The paper proposes a planar piezoelectric actuator design and a piezoelectric suspension made of the planar piezoelectric actuator. The design has a high bandwidth, simple structure and low cost. A prototype of the piezoelectric suspension is designed, fabricated and tested. The experimental results demonstrate that the piezoelectric suspension can satisfy the requirements for the dual-stage servo system.