Air-bearing linear actuator for highly precise tracking

An actuator consisting of a linear air bearing and a voice coil motor (VCM) of the linear type was designed for precise tracking. The stiffness of the air bearing was strong enough so that the moving coil of a VCM fixed to the air bearing slider arm could form a cantilever system. The linear actuator showed a much higher resonance frequency than a conventional rotary actuator. Due to the high resonance frequency, the servo bandwidth became significantly wider. The linear actuator could be stepped at 1 nm resolution without overshoots and undershoots and the rise time was less than 0.5 ms.