Development of shear-mode piezoelectric microactuator for precise head positioning

We have developed a novel piezoelectric micro-actuator for dual-stage actuator systems in magnetic disk drives. This microactuator is based on the shear deformation of piezoelectric elements and drives the head suspension assembly. The actuator is suitable for thin devices and is easily manufactured because of its simple stack configuration. We installed the microactuator in one of Fujitsu's 3.5-inch commercial drives to evaluate the servo system of a dual-stage actuator. The dual-stage actuator system achieved a non-repeatable position error (NRPE) 3sigma of 0.036 mum. The dual-stage servo system reduced the NRPE by 35% compared with the conventional single actuator system, even in HDDs with a high rotational speed of 10000 rpm.