Optimal Feed Forward Profiles for Dynamic Flying Height Control in Hard Disk Drives

摘要

A dynamic model of the resistance heater in a thermal flying height control (TFC) slider of a hard disk drive is identified and used for dynamic flying height control. Experimental data obtained on a spin stand and the generalized realization algorithm are used for identification of a discrete-time dynamic model of the resistance heater (thermal actuator). The flying height change is measured using servo burst information written onto the disk surface. Based on the identified discrete-time model of the heater and convex optimization techniques, a computational scheme is proposed to obtain optimized feed forward input profiles to the heater element that minimize repeatable flying height variations and enable low flying heights.