Optimizing Floating Locations in Hard Disk Drive by Solving Max-min Optimization
For hard disk drive reliability engineers, this work provides a systematic methodology to reduce a critical reliability concern, though it is incremental as it applies known optimization techniques to a specific domain problem.
The paper addresses the problem of minimizing head-bump interference during floating operation in hard disk drives by solving a max-min optimization problem. The proposed heuristic reduces the NP-hard multivariable nonlinear optimization to an arithmetic problem, achieving a desirable trade-off between optimality and computational complexity.
Floating operation is very critical in power management in hard disk drive (HDD), during which no control command is applied to the read/write head but a fixed current to counteract actuator flex bias. External disturbance induced drift of head may result in interference of head and bump on the disk during drifting, leading to consequent scratches and head degradation, which is a severe reliability concern in HDD. This paper proposes a unique systematic methodology to minimize the chances of hitting bump on the disk during drive floating. Essentially, it provides a heuristic solution to a class of max-min optimization problem which achieves desirable trade-off between optimality and computation complexity. Multivariable nonlinear optimization problem of this sort is reduced from NP-hard to an arithmetic problem. Also, worst-case is derived for arbitrary bump locations.