Linear actuator with air bearing for highly precise tracking [HDD]

An actuator consisting of a linear air bearing and a voice coil motor (VCM) of linear type was designed for highly precise tracking in hard disk drive applications. As the stiffness of the air bearing was strong enough, a moving coil of the VCM could be fixed to the air bearing slider arm, forming a cantilever system. Thus, the linear actuator realized showed much a higher resonance frequency than a conventional rotary actuator. Due to the high resonance frequency of the actuator system, the servo bandwidth became wider up to a very high frequency. As a result, the linear actuator could be stepped and fed at 1 nm resolution without overshoots and undershoots, with rise time of less than 0.5 ms.