Servo controller

• US 7,656,106 B2
• Filed: 07/07/2006
• Issued: 02/02/2010
• Est. Priority Date: 07/08/2005
• Status: Active Grant

• Current Assignee: Fanuc Ltd (Fanuc Corporation)
• Original Assignee: Fanuc Ltd (Fanuc Corporation)
• Inventors: Toyozawa, Yukio, Maeda, Kazuomi, Iwashita, Yasusuke
• Primary Examiner(s): Benson; Walter
• Assistant Examiner(s): Colon-Santana; Eduardo
• Application Number:
  US11/482,011
• Publication Number:
  US 20070007926A1
• Time in Patent Office: 1,306 Days
• Field of Search: 318/5, 318/7, 318/68, 318/34, 318/37, 318/51, 318/115, 318/119, 318/560, 318/564, 318/568.1, 318/675, 318/39, 318/570, 318/572
• US Class Current: 318/39
• CPC Class Codes: G05B 19/195 Controlling the position of several slides on one axis
• CPC Class Codes: G05B 19/4141 characterised by a controller or microprocessor per axis

Abstract

There is provided a servo controller for synchronously controlling a master side drive source to drive one drive axis and a slave side drive source to drive the other drive axis. The servo controller includes a correction data calculation means for calculating correction data to correct a positional deviation of a slave side drive source according to a synchronization error which is a difference between a positional deviation of a master side drive source and a positional deviation of the slave side drive source, in which the correction data is added to the positional deviation of the slave side drive source.

Claims

1. A servo controller for synchronously controlling a plurality of drive sources, comprising:

a correction data calculation means for calculating correction data to correct a positional deviation of a slave side drive source according to a synchronization error which is a difference between a positional deviation of a master side drive source to drive one drive axis and a positional deviation of the slave side drive source to drive the other drive axis,

wherein the correction data calculation means comprises a filter portion for restricting a resonance frequency band, a storage portion for storing the correction data at each predetermined period with reference to time so as to conduct learning control and a dynamic characteristic compensation element to compensate a phase delay and a gain reduction for the slave side drive source,

wherein the master side drive source and the slave side drive source are synchronously controlled when the correction data is added to the positional deviation of the slave side drive source.

2. A servo controller according to claim 1, wherein the servo controller is applied to a machine tool, the one drive axis of which is a rotary axis and the other drive axis of which is a feed axis.

3. A servo controller according to claim 2, wherein the machine tool conducts tapping for forming a female screw in a work.

4. A servo controller according to claim 2, wherein the machine tool conducts thread-cuffing for forming a male screw on an outer circumferential face of a work.

5. A servo controller according to claim 1, wherein a movement command sent to the master side drive source and the slave side drive source has an identification number, the servo controller further comprising a changeover means for changing over a storage region, which conducts learning-control, corresponding to the identification number.

6. A servo controller according to claim 1, further comprising a storage means for storing the correction data at each sampling with reference to position so as to conduct learning-control when the time is converted to the position.

7. A servo controller according to claim 1, wherein the servo controller is applied to a machine tool in which two slave side drive sources are provided and the slave side drive sources respectively drive a first feed axis of the tandem structure and the second feed axis of the tandem structure which are arranged in parallel to each other.

8. A servo controller according to claim 7, wherein the correction data calculated according to the synchronization error caused between the master side drive source and one slave side drive source is added to the position deviation of both the slave side drive sources.

9. A servo controller according to claim 7, wherein the correction data calculation means is used in common between the two slave side drive sources, and the two synchronization errors to be inputted into the correction data calculation means are weighted by a predetermined internal ratio according to a load balance between the first and the second feed axis.

10. A servo controller for synchronously controlling a plurality of drive sources, comprising:

a selection means for selecting one of the synchronization error, which is a difference between a positional deviation of a master side drive source to drive one drive axis and a positional deviation of the slave side drive source to drive the other drive axis, and the positional deviation of the slave side drive source; and

a correction data calculation means for calculating correction data to correct the positional deviation of the slave side drive source according to one data selected by the selection means,

wherein the correction data calculation means comprises a filter portion for restricting a resonance frequency band, a storage portion for storing the correction data at each predetermined period with reference to time so as to conduct learning control and a dynamic characteristic compensation element to compensate a phase delay and a gain reduction for the slave side drive source,

wherein the correction data is added to the positional deviation of the slave side drive axis so as to make the positional deviation or the synchronization error come close to zero.