Adaptive disturbance rejection using dead zone filter
AssigneesSeagate Technology LLC, Industry-Academic Cooperation Foundation, Yonsei University
InventorsSung-Won Park, Sung-Yong Lim, Jae-Seong Lee, Hyunseok Yang
Life of this patent
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Abstract
Apparatus and method for disturbance rejection in a control system. In some embodiments, a controller is adapted to position a control object. A disturbance observer generates a disturbance compensation value which is applied to reduce position error resulting from application of mechanical disturbance to the control object. The disturbance observer includes an adaptive filter with at least one dead zone providing a pass-through response with a scalar gain of less than one.
Claims20
An apparatus comprising:
- a control object coupled to an actuation mechanism;
- a controller adapted to position the control object by generating an initial input signal responsive to position error of the control object;
- a disturbance observer circuit which generates a disturbance compensation value to reduce position error resulting from application of mechanical disturbance to the control object, the disturbance observer circuit comprising an adaptive filter circuit with at least one dead zone providing a pass-through response with a scalar gain of less than one, the scalar gain selected responsive to a target stability margin and a disturbance signature associated with the control object;
- and
- a summing block adapted to combine the initial input signal with the disturbance compensation value to form a modified input signal, the modified input signal applied to the actuation mechanism to adjust the position of the control object.
A data storage device, comprising:
- a data read/write transducer adjacent a rotatable data recording medium;
- an actuation mechanism supporting the transducer and configured to move the transducer with respect to the medium;
- a servo controller configured to generate an initial input signal for the actuation mechanism responsive to position error of the transducer;
- and
- a disturbance observer circuit which generates a disturbance compensation value which is combined with the initial input signal to form a modified input signal which is applied to the actuation mechanism to adjust the position of the transducer, the disturbance compensation value reducing position error resulting from application of mechanical disturbance to the data storage device, the disturbance observer circuit comprising an adaptive filter circuit with at least one dead zone providing a pass-through response with a scalar gain of less than one and a dead zone filter circuit that generates a boundary for the dead zone that varies over time in relation to changes in measured position error, the adaptive filter comprising an H-filter that uses least mean squares (LMS) processing of position error samples to reduce the position error of the control object.
A method comprising:
- positioning a control object using a controller;
- determining a position error of the control object;
- generating a disturbance compensation value responsive to application of mechanical disturbance to the control object, the disturbance compensation value generated using an adaptive filter with at least one dead zone providing a pass-through response with a scalar gain of less than one, the scalar gain selected responsive to the determined position error of the control object;
- and
- applying the disturbance compensation value to reduce the position error of the control object, the adaptive filter comprising an H-filter that uses least mean squares (LMS) processing of position error samples to reduce the position error of the control object.
Dependencies are inferred from the claim text.