Esgw Holdings Limited

Doug Frisby

Jim Hargarten

a seek procedure for a hard disk drive which provides a significant reduction in acoustic noise as well as high performance fast seek times is described. The seek procedure lowers the peak acceleration for short seeks and imparts a smooth transition from a sine seek to an exponential arrival at the target track. The seek procedure provides an error free feedforward signal derived from a single sine table. The procedure which contains a time domain sinusoid acceleration feedforward combined with a phase-plane trajectory controlled velocity which, near seek completion. The procedure is constructed so that the acceleration begins at zero and, in the fashion of a sine, increases to a maximum, decreases to a minimum and then increases again until a computed switchpoint is reached. The switchpoint is determined in-situ, to provide a smooth and continuous velocity transition from sinusoid to exponential. The velocity trajectory is computed from a look-up table. The procedure is implemented using conventional seek controller servo components and commercially available operation software.

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Nederland, CO, United States of America

Doug Frisby