Drive including PID position feedback drive and control system fed by speed control unit and X-ray device comprising such a drive
AssigneeU.S. Philips Corporation
InventorMarcel A.G. Boom
Life of this patent
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Abstract
A motor drive having a very large dynamic speed range comprises a PID position feedback control system (8) in which the motor position is readjusted on the basis of the difference between the instantaneous (x.sub.a) and the nominal (x.sub.s) position. A series of nominal positions (x.sub.s) is determined from a nominal speed (v) in a speed control unit (5). The successive nominal positions (x.sub.s (t)) in a series exhibit a constant difference (.DELTA.x) relative to one another and are presented to the PID position feedback control system (8) with fixed intervals (.DELTA.t). A drive of this kind is used, for example in the beam collimator of an X-ray device.
Claims20
A drive, comprising:
- a motor with a motor shaft;
- a feedback control system for positioning the motor shaft in a nominal position represented by a position command signal, and an input for receiving the position command signal, and
- a speed control unit having an input for receiving a velocity command, said speed control unit being arranged to produce the position command signal in response to the velocity command such that the position command signal represents a series of nominal positions which are presented with differences (.DELTA.x) between successively presented nominal positions having substantially a same value, and time intervals (.DELTA.t) between successively presented nominal positions having substantially a same value, by at least calculating the value of the time intervals (.DELTA.t) such that the value of the time intervals (.DELTA.t) is changed in response to a change in the velocity control signal, and to supply the position command signal to the input of the feedback control system.
An X-ray device, comprising an X-ray source and a displaceable shutter which is arranged in front thereof which is driven by a drive comprising:
- a motor with a motor shaft;
- a feedback control system for positioning the motor shaft in a nominal position represented by a position command signal, and an input for receiving the position command signal, and
- a speed control unit having an input for receiving a velocity command, said speed control unit being arranged to produce the position command signal in response to the velocity command such that the position command signal represents a series of nominal positions which are presented with differences (.DELTA.x) between successively presented nominal positions having substantially a same value, and time intervals (.DELTA.t) between successively presented nominal positions having substantially a same value, by at least calculating the value of the time intervals (.DELTA.t) such that the value of the time intervals (.DELTA.t) is changed in response to a change in the velocity control signal, and to supply the position command signal to the input of the feedback control system.
Dependencies are inferred from the claim text.