Optimal Design Of A Disk Drive System
Free (open access)
E. Baltaci & N. K. Jha
A methodology for optimum mechanical design of a disk drive system has been proposed. A mathematical model for the minimisation of seek time along with constraints for positive and negative skew angle, physical boundaries for the actuator, coil holder housing, linear side of the disc center, and resonant frequencies have been developed. The geometric programming technique has been used to find the optimal size of disc parameters Rarm, and bearing coordinates Bx and By. The visual basic has been used to generate an automatic mathematical model. Keywords: disk drive, magnetised data, disk drive components, optimal design, geometric programming, constraints. 1 Introduction Magnetic hard-disk drives are used to access data by personal computers and workstations. The data is stored as tiny magnetized elements, called bits, Data is arranged in sectors along a number of concentric tracks as in Fig.1. These tracks are arranged from the inner diameter of the disk to its outer edge . In modern disk drives, the bits are written and read by separate elements in a recording head as it flies over the spinning disk. The head itself is attached to a slider, an aerodynamically shaped block that allows the head to maintain a consistent flying height above the disk. In turn, the slider is connected to a suspension arm that is controlled by an actuator which can move the head from the inner to the outer diameter on the disk Sometimes the heads move ahead of the required positions and it is called overshoot . Bits are closer together at the inner diameter (ID) and signal levels are larger at the outer diameter (OD). Normally three parameters are associated with the disk surface; i) track density, ii) bit density, iii) flux change density. The headstack is prevented from reading the spindle or the outer edge of the disk by the crash stops. Crash stops must be
disk drive, magnetised data, disk drive components, optimal design, geometric programming, constraints.