Modeling and Simulation for Head/Disk Electromechanical Systems Interface During Load/Unload Process of a Hard Disk Drive

This paper presents a novel design and reliability assessment simulator focusing on HDD (Hard Disk Drive)’s L/UL (Load and Unload) operations. The model is structured to incorporate theoretical effects of environmental factors, component variations, and temperature effects in addition to empirical dependencies on product operating mode. The simulator includes detailed model of VCM (Voice Coil Motor), spindle motor, PLSI (Power Large Scale Integration), and all other related components and their effects on the load and unload operations. The tool can be used for feasibility assessment of new electromechanical designs and available design margins, and it is also a reliable tool to provide accurate tunings for FW (firmware) Load, Unload, Emergency Unload and EPOR (Emergency Power Off Retract). The simulator is also capable of accurately estimating the potential DPPM (Defective Part Per Million) related to the various potential failures using latest statistical analysis. The predictions and performance reliability of the model have been verified experimentally through comparison with HDD product reliability test data.