公开(公告)号：CA1078512A

公开(公告)日：1980-05-27

申请号：CA252636

申请日：1976-05-14

Applicant: IBM

Inventor： COMMANDER ROBERT D ,  TAYLOR JOHN R

IPC: G05D3/12 ,  G11B5/55 ,  G11B5/596 ,  G11B21/08 ,  G11B21/10 ,  G11B5/82

Abstract: POSITIONING SYSTEM FOR DATA STORAGE APPARATUS Data storage apparatus comprises a movable record medium with at least one data record-and-playback head for recording data on and/or reading data from tracks on the medium. An actuator moves the data head or heads from track to track as required by external apparatus, the movement being controlled by reference to servo tracks pre-recorded on the medium and read by a servo head ganged for movement to the data head or heads. Each servo track consists of regions alternating between first and second states, transitions from a first to a second state and from a second to a first state being capable of producing different distinguishing signals in the servo head. Sections of the servo tracks are laterally displaced with respect to undisplaced sections by a distance less than one track width, the location of the displaced sections being selected such that the lateral displacement of servo tracks at the start and end of a section do not produce changes detectable by the servo head.

公开(公告)号：FR2375688A1

公开(公告)日：1978-07-21

申请号：FR7734665

申请日：1977-11-10

Applicant: IBM

Inventor： COMMANDER ROBERT D ,  GARDNER PETER A

IPC: G05D3/12 ,  G11B5/596 ,  G11B21/10 ,  G11B5/02

Abstract: A data storage apparatus, such as an accessing head magnetic disk file, includes at least one data disk surface and a servo disk surface. In operation, a continuous position signal having high frequency components is derived from the servo surface, which has a quadature type servo signal prerecorded thereon. A circuit means modifies the derived position signal so that a substantially linear signal representing the displacement of the servo head from the servo track is obtained. A second position signal having a low frequency component is obtained from servo sector information registered on the data disk surface and together with the first position signal forms a hybrid position signal. This hybrid signal is used to control the movement of the data heads relative to the data tracks to ensure optimum transducing operation.

公开(公告)号：FR2319179A1

公开(公告)日：1977-02-18

申请号：FR7618346

申请日：1976-06-09

Applicant: IBM

Inventor： CASE WILLIAM J ,  COMMANDER ROBERT D

IPC: G05D3/12 ,  G05B11/36 ,  G11B5/596 ,  G11B21/10 ,  G11B21/08

Abstract: Data track positioning information for data tracks on a stack of recording disks is provided by servo information pre-recorded on one surface of the stack. In addition, each data track on the remaining surfaces of the stack has servo information relative to that track pre-recorded in sectors around the track. Track following operations are controlled in a closed loop servo system using on-track position information derived from the sectored servo tracks associated with the track being followed. The bandwidth of the position error signal derived from the sectored servo information is increased by adding high frequency components obtained from the continuous servo information on the servo surface. Track access operations are controlled using track crossing information derived from the pre-recorded servo information on the servo surface.

公开(公告)号：CA960772A

公开(公告)日：1975-01-07

申请号：CA134455

申请日：1972-02-10

Applicant: IBM

Inventor： COMMANDER ROBERT D ,  DIXON JERRY D

IPC: G05B19/23 ,  G05D3/14 ,  G11B5/55

Abstract: According to the present invention a movement control system comprises a motor for moving said body into a required position, a motor control unit for controlling the acceleration and deceleration of said motor, a position indicator unit producing positioning signals corresponding to movement of said body while accelerating toward said required position, and a calculating unit responsive to position data representing said required position and to said positioning signals to produce a control signal for said motor control unit to change from acceleration to deceleration in order to provide required speed/position characteristics for the movement of said body.

公开(公告)号：CA1248583A

公开(公告)日：1989-01-10

申请号：CA470452

申请日：1984-12-18

Applicant: IBM

Inventor： COMMANDER ROBERT D ,  FENTON BRIAN P ,  RAMAGE JOHN G

IPC: H02M7/537 ,  H02M7/5387 ,  H03K17/691 ,  H02M3/335 ,  H02P6/02 ,  H02P1/18

Abstract: A power switching circuit for switching power repetitively to a load at a relatively low frequency employs a power switching device which is driven across an isolating transformer interface. The drive signals are high frequency pulse signals which are modulated with the low frequency switching information, the modulations being detected in the secondary circuit of the transformer. Such an arrangement affords isolated driving with fast switching edges and requires only a small transformer. Power for the detection circuit is derived by rectification of the high frequency signals induced in the transformer secondary.

公开(公告)号：CA1109558A

公开(公告)日：1981-09-22

申请号：CA290791

申请日：1977-11-14

Applicant: IBM

Inventor： COMMANDER ROBERT D ,  GARDNER PETER A E ,  TAYLOR JOHN R

IPC: G05D3/12 ,  G11B5/596 ,  G11B21/10 ,  G11B5/012

Abstract: Data storage apparatus of the type employing a stack of rotatable storage disks accessible by a plurality of data heads ganged for movement over the data surfaces. The position of a data head during track following operations over a selected data surface being controlled by a hybrid servo signal consisting of low frequency components of position information signals derived from servo sectors around the data track being followed added to which are high frequency components of continuous position information signals derived either from a dedicated servo surface forming part of the stack or from an external position transducer. The continuous position information being provided by a servo transducer, which is also ganged to the data heads, in the form of two cyclic quadrature signals (90.degree. out of phase with each other) each having portions which are linear and co-extensive over the whole range of head displacement. The apparatus including servo control circuits for detecting during data track following position (caused for example by temperature variations or mechanical vibrations) beyond the linear region of the corresponding one of the two quadrature signals supplying the high frequency components and, upon such detection, switching to an adjacent linear portion of the other signal, or the inverse of the other signal, to either of which has been added an appropriate d.c. offset so that the linear portion of this other signal becomes an effective extension of the linear portion of the continuous servo signal corresponding to the data track being followed. By this means the a.c. gain of the servo circuits is maintained constant thereby improving the servo loop performance.

公开(公告)号：CA1079845A

公开(公告)日：1980-06-17

申请号：CA256686

申请日：1976-07-09

Applicant: IBM

Inventor： CASE WILLIAM J P ,  COMMANDER ROBERT D

IPC: G05D3/12 ,  G05B11/36 ,  G11B5/596 ,  G11B21/10 ,  G11B5/56 ,  G11B17/00

Abstract: DATA STORAGE APPARATUS Data track position information for data tracks on a stack of recordingdisks is provided by servo information pre-recorded on one surface of the stack. In addition, each data track on the remaining surfaces of the stack has servo information relative to that track pre-recorded in sectors around the track. Track access operations are controlled using track crossing information derived from the pre-recorded servo information on the servo surface and track following operations are controlled in a closed loop servo system using on-track position information derived from the sectored servo tracks associated with the track being followed. The bandwidth of the position error signal derived from the sectored servo information is increased by adding high frequency components obtained from the continuous servo information on the servo surface.

公开(公告)号：FR2311374A1

公开(公告)日：1976-12-10

申请号：FR7610359

申请日：1976-04-01

Applicant: IBM

Inventor： COMMANDER ROBERT D ,  TAYLOR JOHN R

IPC: G11B5/55 ,  G05D3/12 ,  G11B5/596 ,  G11B21/08 ,  G11B21/10 ,  G11B5/02

Abstract: A positioning system for data storage apparatus in which a magnetic transducer is positioned relative to data tracks on a moving record member by means of a closed loop servo system. Improved velocity control information is provided to the servo system by pre-recorded servo tracks read by a single servo head forming part of the closed loop system. Each servo track consists of a plurality of servo cells, alternate ones of which are laterally displaced by half a track width. A position reference signal is prerecorded in each cell at a point which is predetermined to permit the signal to be sensed by the single servo head independently of any other detectable signal. Accordingly, a position error signal derived from displaced cells is always 90 DEG out of phase with the position error signal derived from undisplaced cells. During a track access operation, when the servo head is moved from one track to another track, the displaced and undisplaced cells are sensed by the single servo head to provide two separate position error signals. Control circuits combine selected portions of the two position error signals to provide a composite signal of improved linearity from which the velocity of the head during the access operation can be ascertained directly and employed to perform control functions dependent on velocity.