A MINIMUM-TIME SEEK CONTROLLER FOR A DISK-DRIVE

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.