Head-positioning control system using thermal actuator in hard disk drives

In this paper, we propose a head-positioning control system with a thermal actuator in hard disk drives (HDDs). The frequency response of the thermal actuator showed that the thermal actuator system has no mechanical resonant mode. Therefore, this head-positioning system with a thermal actuator can control the head-position beyond the major mechanical resonances caused by a voice coil motor (VCM) or suspensions. In this study, the system was a dual-stage actuator system; the first actuator was a VCM, and the second was a thermal actuator. Simulation results for a track-following control in an HDD demonstrated the validity of the proposed method.