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.