US 6,034,498 AGranted

Servo adjustment method and apparatus therefor

AssigneeToshiba Kikai Kabushiki Kaisha

InventorsMinoru Hamamura, Sadaji Hayama, Jun Fujita

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Abstract

Response delay error is calculated from an instructed position based on a position of a moving body and a position instruction to detect reversal of a servo motor and to compare response delay error produced in reversal of the servo motor and threshold value. In the case where response delay error is a threshold value or greater, the value of the already determined compensation torque is updated into a value that enables the response delay error to be decreased, and allows the moving body to carry out circular arc complementary feed motion under the same condition to compensate, based on the updated compensation torque, instructed torque for instructing the servo motor when reversal of the servo motor is detected. Compensating the instructed torque and updating the compensation torque is repeated until the response delay error is at the threshold value or less. Thus, a reasonable compensation torque is determined such that response delay error at the time of reversal of the servo motor is minimized.

Claims7

Dependent claims

An adjustment method for a servo mechanism of servomotors for driving a first feed shaft and a second feed shaft of a moving body, the method comprising:

controlling the servomotor of one of the feed shafts while detecting a position of the moving body so that the moving body follows an instructed position to allow the moving body to move in a circular interpolation feed motion under a condition of a designated circular arc radius and a feed rate;
detecting a reversal of the servomotor in which a direction of motion of the moving body changes;
detecting a torque signal sent to the servomotor at the reversal;
calculating a response error deviated from an instructed position based on the position of the moving body and the instructed position;
setting a compensation torque to a predetermined value for serving as a first reference value for correcting an instructed torque;
setting a threshold value for serving as a second reference value for updating the compensation torque;
comparing the response error produced in the reversal of the servomotor with the threshold value;
updating a value of the determined compensation torque into a value that enables the response error to be decreased in a case where the response error is greater than the threshold value, and allows the moving body to carry out the circular interpolation feed motion in the case where the response error is greater than the threshold value;
compensating, based on the updated compensation torque, the instructed torque which is sent to the servomotor in detecting the reversal of the servomotor to update the compensation torque when the response error is greater than the threshold value;
and repeatedly carrying out compensation of the torque and updating the compensation torque until the response error is within the threshold value.

7 more elements

An adjustment apparatus for a servo mechanism of servomotors for driving a first feed shaft and a second feed shaft of a moving body,

the apparatus comprising:
first position detecting means for detecting a position of the moving body driven by a servomotor of the first feed shaft;
second position detecting means for detecting a position of the moving body driven by a servomotor of the second feed shaft;
a servo mechanism for controlling the servomotors of the feed shafts while detecting the position of the moving body such that the moving body follows an instructed position to allow the moving body to move in a circular interpolation feed motion under the condition of a designated circular arc radius and feed rate;
means for detecting a reversal of the respective servo motors;
means for calculating a response error deviated from an instructed position based on the detected position of the moving body and the instructed position;
means for comparing the response error produced at the reversal of the servomotor with a predetermined threshold value;
means for compensating, based on a predetermined compensation torque, the instructed torque which is sent to the servomotor to decrease the response error;
and
means for updating the value of the already determined compensation torque in a case where the response error is greater than the threshold value, into a value that enables the response error to be decreased.

7 more elements

Dependencies are inferred from the claim text.

Facts

Application: 09/108,305Filed 1 Jul 1998
Priority: JP 9-1772642 Jul 1997
Granted: 7 Mar 2000
Term ends: Not estimatedThe source records don’t support an estimate.

Classification5 codes

G05B 19/404
Numerical control [NC], i.e. automatically operating machines, in particular machine tools, e.g. in a manufacturing environment, so as to…
G05B 2219/41079
Servomotor, servo controller till figures: cross coupled backlash for two other axis on reversing third axis
G05B 2219/41084
Servomotor, servo controller till figures: compensation speed axis with changing, reversing direction, quadrant circle
G05B 2219/41138
Servomotor, servo controller till figures: torque compensation