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公开(公告)号：DE2966005D1
公开(公告)日：1983-09-01
申请号：DE2966005
申请日：1979-11-27
Applicant: IBM
Inventor： TAYLOR JOHN RICHARD , LAISHLEY WILLIAM JOHN
Abstract: A sampled data servo positioning system employs an actuator (50) to move a member between a current and a target position. Incremental position feedback is provided only at sampling times. The system employs a model (60,61, 64) responsive to a velocity related input signal to produce a continually available model incremental position signal. Phase comparing means (70) indicates phase differences between the model and sampled position signals at the sampling times.The system has two operational configurations in the first of which a source of saturation control signals is connected to the actuator to cause maximum acceleration or deceleration thereof. In this first configuration, the model is forced to track the actuator motion by means of feed-forward plus feedback control. The feedforward signal represents actuator performance while the feedback signal is the position signal phase difference. In the second operational configuration, a velocity profile signal is applied to the model and the actuator is forced to track the model by means of feedfoward plus feedback control. The feedback signal is again the position signal phase difference but the feedforward signal is a predetermined signal representing the desired actuator current to execute the velocity profile. The sampled data servo positioning system may be the access motion control system of a sector servo disk file.
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Patent Agency Ranking
公开(公告)号：AU1401676A
公开(公告)日：1977-12-01
申请号：AU1401676
申请日：1976-05-17
Applicant: IBM
Inventor： COMMANDER ROBERT DUNCAN , TAYLOR JOHN RICHARD
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.
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公开(公告)号：CH609797A5
公开(公告)日：1979-03-15
申请号：CH604476
申请日：1976-05-14
Applicant: IBM
Inventor： COMMANDER ROBERT DUNCAN , TAYLOR JOHN RICHARD
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.
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公开(公告)号：DE2755652A1
公开(公告)日：1978-06-29
申请号：DE2755652
申请日：1977-12-14
Applicant: IBM
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.
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公开(公告)号：DE2612111A1
公开(公告)日：1976-11-18
申请号：DE2612111
申请日：1976-03-22
Applicant: IBM
Inventor： COMMANDER ROBERT DUNCAN , TAYLOR JOHN RICHARD
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.
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公开(公告)号：DE2502630A1
公开(公告)日：1975-08-14
申请号：DE2502630
申请日：1975-01-23
Applicant: IBM
Inventor： TAYLOR JOHN RICHARD
Abstract: In a phase locked oscillator (PLO), the frequency of a voltage controlled oscillator (VCO) is changed in response to error signals indicating the phase error between the individual pulses of a stream of input pulses and the output pulses of the PLO. The running of the PLO is temporarily interrupted whenever the phase error exceeds a predetermined amount, and is restarted in phase with the next input pulse from the stream of pulses. A residual part of the error signal causing the interruption is accumulated so that after each interruption the frequency of the oscillator is closer to the frequency of the input stream of pulses. The process is repeated as required until phase lock is achieved.
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