Adaptive flying height control based on hybrid actuator in near-field optical disk drives

In the next generation near-field optical data storage systems, higher data transfer rate and higher data density require the optical pickup head to maintain a constant sub-micrometer flying height above the rotating disk surface without any collisions. However, suspension vibration and force disturbance, as well as disk vibration make it difficult to maintain the desired flying height during disk operation in the near-field optical disk drives (ODD). It is proposed in this paper to design a hybrid actuator system which combines both advantages of the flying slider used in hard disk drives and the voice coil actuator used in optical disk drives. Then based on the developed model of the hybrid actuator, an adaptive regulation approach is proposed to regulate the flying height at its desired value, despite the unknown vibrations and the unknown force disturbance. Simulation results are presented to illustrate the capability of the proposed adaptive regulation approach to achieve and maintain the desired flying height.