An advanced sector servo using a learning, estimating and over-sampling method for a 3.5" 28 Mbyte FDD

The authors developed an advanced sector servo which was used in a 28-Mbyte flexible magnetic disk drive (FDD). This sector servo uses a learning method which estimates a continuous track position error between servo sectors based on the information from an external position encoder and an over-sampling method which samples position error at a higher sampling rate. As a result, the authors achieved fine-trackability and high vibration-resistance performance without an increase in the number of servo sectors. The head positioning control system using these methods and the control performances are described. >