US 4,906,908 AGranted

Method for numerical position control of motor-driven shafts

AssigneeSiemens Aktiengesellschaft

InventorsWolfgang Papiernik, Thomas Baer, Gerhard Kirchner

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Abstract

In a method for numerical position control of motordriven shafts whose rotations are to be synchronous with one another under a certain transmission ratio a control loop is provided for each shaft. A speed setpoint, weighted with the corresponding transmission ratio, is applied as a position setpoint per unit of time simultaneously to the control loops of the respective shafts. If the actual speeds of the shafts differ from one another due to a disturbance within the controlled system, the difference between these actual speeds is used to readjust the speed and the position within the speed controlled section of one of the control loops. Overshoot of the position of a shaft, which might be caused by direct adding of the position setpoint onto the speed control loop is avoided by the fact that a control element produces a delay having the time response corresponding to a delay introduced by the respective control section for speed and adds this delay to the position setpoint prior to integration (14 to 17, 24 to 27).

Claims6

Dependent claims

A method for the numerical position and control of a system having a plurality of shafts including at least a motor driven master shaft and a motor driven slave shaft with a given transmission ratio with respect to said master shaft;

each of said motor driven shafts having its own control loop comprising a predetermined structure with a control section for speed and each loop having means for adjusting transient times associated with that loop and further including a means for supplying input signals as speed setpoints as position setpoints per unit time the position of each shaft being adjustable in response to the said input signals comprising the steps of:
(a) forming the predetermined structure of each of said control loops for each of said shafts from identical structure;
(b) adjusting said means for adjusting of the control loops for each of said shafts to produce the same transient time for each shaft and associated loop;
(c) generating a position setpoint for each respective slave shaft from a position setpoint of its respective master shaft by weighting said position setpoint of the respective master shaft with the respective transmission ratio;
(d) comparing the resultant actual speed of each respective master shaft with the resultant actual speed of its associated slave shaft taking into consideration the transmission ratio therebetween;
(e) readjusting the speed of the respective slave shaft if a difference between resultant actual speeds is determined, a state compensating controller providing an input to the control section for speed of the respective slave shaft to adjust the actual speed of the slave shaft.

3 more elements

Dependencies are inferred from the claim text.