Abstract
Increasing track density (TPI) is effective to realize an ultra-high density magnetic recording. As a very narrow track width of a magnetic head is required for the high TPI, a spin-stand system must follow precisely on narrow tracks. Though the spin-stand system owes accuracy to its large mechanical stiffness, the system will be difficult to follow on the narrow t rack w ithin 1 nm track e rror. Therefore, w e p ropose a p recise t racking a ctuator for the spin-stand system like a piggyback actuator. The actuator consists of a piezoelectric element and an expansion mechanism, the actuator control system is built by using a DSP system and an optical fiber displacement sensor. Since the track follow control on the spin-stand must allow various sizes of HGA without servo tuning, we approach a robust controller based on H∞ control theory.
