Apparatus and method for displacing movable system with respect to a data carrier

A method of shifting a head which is movable relative to a carrier for recorded information carried by a plurality of recording tracks, the addresses of the tracks being recorded on the carrier in a plurality of reference zones, at least equal in number to the number of tracks, each track being associated with at least one zone, the head being moved by a motor and reading the addresses, the head being shifted from a starting track A to a destination track B, comprising the steps of accelerating the head from track A to an intermediate track C by supplying the motor with a constant voltage, after the head has reached track C reversing the polarity of the constant voltage as a function of the actual acceleration magnitude of the head and addresses read by the head so the head is decelerated and stops at track B.

Apparatus for displacing a movable system with respect to a data carrier on which are recorded a plurality of tracks having addresses written within a plurality of reference zones, the number of reference zones being at least equal to the number of tracks, each track being associated with at least one zone, the movable system being driven by a motor, and including at least one data read head which is displaced from a starting track to an address arrival track, said apparatus comprising means responsive to the read addresses derived from the head for deriving a signal indicative of an acceleration instruction .gamma..sub.c, means coupled to the system for measuring the acceleration .gamma. of the system and for deriving a signal indicative of .gamma., means responsive to the signals indicative of .gamma..sub.c and .gamma. for comparing .gamma..sub.c and .gamma. and deriving an error signal, and means responsive to the error signal for controlling the motor.

Apparatus for shifting a head which is movable relative to a carrier for recorded information carried by a plurality of recording tracks, the addresses of the tracks being recorded on the carrier in a plurality of reference zones at least equal in number to the number of tracks, each track being associated with at least one zone, the head reading the addresses, the head being shifted from a starting track A to a destination track B, comprising means for accelerating the head from track A to an intermediate track C and for decelerating the head when it reaches track C so the head stops at track B, said means for accelerating and decelerating including means for calculating an acceleration instruction in response to addresses read by the head and for deriving a signal indicative of the acceleration instruction, means for measuring the head acceleration and for deriving a signal indicative of measured head acceleration, means responsive to the acceleration instruction and the measured head accleration signals for deriving an error signal, and means for controlling the speed of the head as a function of the error signal.

In combination, a head which is movable relative to a disc for recorded information carried by plural concentric recording tracks on the disc, addresses of the tracks being recorded on the disc in a plurality of reference zones at least equal in number to the number of tracks, each track being associated with at least one zone, the head reading the recorded information and addresses, the head being shifted from a starting track A to a destination track B, an electric motor for driving said head, means for controlling the motor so the head is accelerated from track A to track C while the head is traveling from track A to track C and the head is decelerated when the head reaches track C, track C being between tracks A and B, said means for controlling including means for calculating an acceleration instruction signal for the head in response to addresses read by the head, means for measuring the acceleration of the head and for deriving a signal indicative of the measured acceleration, means responsive to the instruction and measured acceleration signals for deriving an error signal, and means responsive to the error signal for controlling the voltage supplied to the motor.

Apparatus for shifting a head which is movable relative to a carrier for recorded information carried by a plurality of recording tracks, the addresses of the tracks being recorded on the carrier in a plurality of reference zones at least equal in number to the number of tracks, each track being associated with at least one zone, the head being moved by a motor and reading the addresses, the head being shifted from a starting track A to a destination track B, comprising means for accelerating the head from track A to an intermediate track C and for decelerating the head when it reaches track C so the head stops at track B, said means for accelerating and decelerating including means for applying a constant amplitude voltage of one polarity to the motor while the head is being accelerated and for applying opposite polarity voltage pulses of differing polarity to the motor while the head is being decelerated, said voltage pulses having said amplitude and progressively narrower widths, except that the last two pulses have the same width.

In combination, a head which is movable relative to a disc for recorded information carried by plural concentric recording tracks on the disc, addresses of the tracks being recorded on the disc in a plurality of reference zones at least equal in number to the number of tracks, each track being associated with at least one zone, the head reading the recorded information and addresses, the head being shifted from a starting track A to a destination track B, an electric motor for driving said head, means for controlling the motor so the head is accelerated from track A to track C while the head is traveling from track A to track C and the head is decelerated when the head reaches track C, track C being between tracks A and B, said means for controlling including means for applying a constant amplitude voltage of one polarity to the motor while the head is being accelerated and for applying opposite polarity voltage pulses of differing polarity to the motor while the head is being decelerated, said voltage pulses having said amplitude and progressively narrower widths, except that the last two pulses have the same width.

Apparatus for controlling the movement of a head reading addresses from plural reference zones written on a data carrier, the number of reference zones being equal in number to the number of data tracks on the carrier, addresses of the tracks being written in the reference zone whereby each track is associated with at least one zone, said apparatus including a motor for driving the head, a circuit for deriving destination addresses for the head, means responsive to the actual acceleration of the head for deriving an actual acceleration signal, and means for combining the actual acceleration signal with signals indicative of the read and destination addresses for deriving a control signal for the motor to enable the motor to drive the head to the destination address.

A method of shifting a head relative to a magnetic disc for recorded information carried by plural concentric recording tracks on the disc, addresses of the tracks being recorded on the disc in a plurality of reference zones at least equal in number to the number of tracks, each track being associated with at least one zone, the head reading the recorded information and addresses, the head being shifted from a starting track A to a destination track B, an electric motor for driving said head, said method comprising controlling the motor so the head is accelerated from track A to track C while the head is traveling from track A to track C and the head is decelerated when the head reaches track C, track C being between tracks A and B, calculating an acceleration instruction for the head in response to addresses read by the head, measuring the acceleration of the head, responding to the instruction and measured accelerations for deriving an indication of an error between them, and controlling the motor in response to the error indication.