Improved air gap control using optimized antishock control algorithm for SIL-based near-field storage system

In this paper, the optimized anti-shock control algorithm is developed and implemented in an solid immersion lens (SIL)-based near-field (NF) storage systems to improve air gap control performance during dynamic conditions. Accordingly, to detect the stable gap error signal under continuous operating conditions, the air gap control performance must be increased to avoid collisions due to external shocks. In this study, we propose an anti-shock air gap control system using a double disturbance observer (DOB) and a dead-zone non-linear controller. Experimental results demonstrate that a double DOB with a dead-zone non-linear controller maintained the optical head with SIL optics for a 5.31 G@10 ms shock. Thus, the air gap control performance in the presence of external shocks was improved.