Improvement of HDD tracking performance using nonlinear compensation and RPT control

Abstract

Pivot bearing friction and flex cable nonlinearity are the two major torque nonlinearities which lead to performance degradation in hard disk drive (HDD) servo systems. Based on a comprehensive model of typical voice-coil-motor (VCM) actuator, which explicitly captures the characteristics of pivot bearing friction and flex cable nonlinearity, this paper presents a design of a parameterized controller for HDD servo systems using the Robust and Perfect Tracking (RPT) technique combined with nonlinear torque compensation and integral enhancement. Simulation and experimental results show that the controller can achieve fast settling time and eliminate static errors in HDD track following task.