Multi-layer bulk PZT actuators for flying height control in ruggedised hard disk drives

When a hard disk drive is operated under hostile conditions fluctuations of the head flying height affect data-transfer, eventually leading to complete data-transfer failure. A test facility has been developed to enable data-transfer and their associated failure mechanisms to be characterised. In order to circumvent this problem and to obtain greater control of the head flying height a novel suspension arm has been developed which incorporates multi-layer bulk PZT actuators. This will enable real-time active adjustment of the head flying height with high precision and accuracy, while the disk drive is in operation. The arm developed is tested dynamically and characterised, and specialised closed-loop control algorithms developed to position and control the head above the disk surface