Head-disk spacing control for an advanced rotary tester

This paper discusses head-disk spacing (HDS) control for an advanced rotary tester (ART). With active control of HDS, the ART enables testing of individual recording head sliders and evaluation of novel magnetic recording processes with great flexibility. In this paper, system characterization and servo control design for the ART are presented. Various hardware and design issues are addressed and the corresponding solutions are provided. Simulation and experimental results show that the nominal HDS can be controlled to be within 10 nm with a standard variation of 1.5 nm.