A time optimal controller design is proposed for the purpose of steeri
ng the read/write head of a magnetic disk drive during a seek manuever
. The design includes the development of a switch-on-time (SOT) open l
oop slew control using a third order model of the voice coil motor. Th
e SOT algorithm employs a look up table of switch times versus angle.
A perturbation correction stage is included to tailor the switch times
to adjust for variations in the operating characteristic of the disk
drive (due, for example to heat buildup, wear, etc.). The design also
includes a terminal stage servo control that employs an optimal feedba
ck/feedforward controller which is used to provide precise positioning
at the end of the seek maneuver.