Servo controller

• US 6,534,944 B2
• Filed: 03/27/2001
• Issued: 03/18/2003
• Est. Priority Date: 03/27/2000
• Status: Active Grant

• Current Assignee: Fanuc Ltd (Fanuc Corporation)
• Original Assignee: Fanuc Ltd (Fanuc Corporation)
• Inventors: Sonoda, Naoto, Toyozawa, Yukio
• Primary Examiner(s): Nappi, Robert E.
• Assistant Examiner(s): Duda, Rina I.
• Application Number:
  US09/817,204
• Publication Number:
  US 20010028228A1
• Time in Patent Office: 721 Days
• Field of Search: 318/41, 318/47, 318/49, 318/51, 318/85, 318/705, 318/568.22, 318/611, 318/623, 318/625, 318/632
• US Class Current: 318/625
• CPC Class Codes: G05B 19/19 characterised by positioning or contouring control systems, e.g. to control position from one programmed point to another or to control movement along a programmed continuous path
• CPC Class Codes: G05B 2219/34027 Dual servo controller, for two motors
• CPC Class Codes: G05B 2219/41234 Design, modeling of position controller
• CPC Class Codes: G05B 2219/41264 Driven by two motors
• CPC Class Codes: G05B 2219/42062 Position and speed and current
• CPC Class Codes: G05B 2219/49262 Two drives at both sides of long tool
• CPC Class Codes: G05B 2219/50228 Synchronize two slides, portal gantry, raising, moving

Abstract

A servo controller capable of driving a single movable member by two motors with high loop-gain setting to obtain a quick response. A servo controller includes two position controllers associated with respective motors and a damping controller. Each of the position controllers has a position control section to output a velocity command based on an identical position command from a host controller and a position feedback value from an associated position detector, a velocity control section to output a current command based on the velocity command and a velocity feedback value from an associated velocity detector, and a current control section to output a voltage command based on the current command and a current feedback value from an associated current detector. The damping controller outputs a current command correction value for compensating an interference between the two motors based on the velocity feedback values from the velocity detectors for the two motors. The current command correction value is added to or subtracted from the current command in the position controller for one of the two motors and is subtracted from or added to the current command in the other position controller for the other of the two motors.

Claims

1. A servo controller for controlling two motors for cooperatively driving a single movable member of a machine, comprising:

a position controller provided for each of the two motors, each of said position controllers having a position control section to output a velocity command based on an identical position command from a host controller and a position feedback value from an associated position detector provided at the machine, a velocity control section to output a current command based on the velocity command outputted from said position control section and a velocity feedback value from a velocity detector provided at an associated motor, and a current control section to output a voltage command based on the current command outputted from said velocity control section and a current feedback value from a current detector for detecting a current of the associated motor, to operate a current amplifier in accordance with the voltage command; and

a damping controller to output a current command correction value for compensating an interference between the two motors based on the velocity feedback values from the velocity detectors for the two motors, said current command correction value being added to or subtracted from the current command in the position controller for one of the two motors and is subtracted from or added to the current command in the other position controller for the other of the two motors,

wherein said damping controller comprises first computing means for integrating a deviation between the velocity feedback values from the velocity detectors associated with the two motors and multiplying the integrated value by a first constant, and second computing means for multiplying the deviation of the velocity feedback values by a second constant, outputs of said first and second computing means being added together for use as said current command correction value.

2. A servo controller according to claim 1, wherein said damping controller further includes phase advancing/compensating means for advancing a phase of the current command correction value.

3. A servo controller for controlling two motors for cooperatively driving a single movable member of a machine, comprising:

a position controller provided for each of the two motors, each of said position controllers having a position control section to output a velocity command based on an identical position command from a host controller and a position feedback value from an associated position detector provided at the machine, a velocity control section to output a current command based on the velocity command outputted from said position control section and a velocity feedback value from a velocity detector provided at an associated motor, and a current control section to output a voltage command based on the current command outputted from said velocity control section and a current feedback value from a current detector for detecting a current of the associated motor, to operate a current amplifier in accordance with the voltage command; and

a damping controller to output a current command correction value for compensating an interference between the two motors based on the velocity feedback values from the velocity detectors for the two motors, said current command correction value being added to or subtracted from the current command in the position controller for one of the two motors and is subtracted from or added to the current command in the other position controller for the other of the two motors,

wherein said damping controller comprises computing means for integrating a deviation between the velocity feedback values from the velocity detectors associated with the two motors and multiplying the integrated value by a constant, an output of said computing means being used as said current command correction value.

4. A servo controller for controlling two motors for cooperatively driving a single movable member of a machine, comprising:

a position controller provided for each of the two motors, each of said position controllers having a position control section to output a velocity command based on an identical position command from a host controller and a position feedback value from an associated position detector provided at the machine, a velocity control section to output a current command based on the velocity command outputted from said position control section and a velocity feedback value from a velocity detector provided at an associated motor, and a current control section to output a voltage command based on the current command outputted from said velocity control section and a current feedback value from a current detector for detecting a current of the associated motor, to operate a current amplifier in accordance with the voltage command; and

a damping controller to output a current command correction value for compensating an interference between the two motors based on the velocity feedback values from the velocity detectors for the two motors, said current command correction value being added to or subtracted from the current command in the position controller for one of the two motors and is subtracted from or added to the current command in the other position controller for the other of the two motors,

wherein said damping controller comprises computing means for multiplying a deviation between the velocity feedbacks values from the velocity detectors associated with the two motors by a constant, an output of the computing means being used as said current command correction value.

5. A servo controller for controlling two motors for cooperatively driving a single movable member of a machine, comprising:

a position controller provided for each of the two motors, each of said position controllers having a position control section to output a velocity command based on an identical position command from a host controller and a position feedback value from an associated position detector provided at the machine, a velocity control section to output a current command based on the velocity command outputted from said position control section and a velocity feedback value from a velocity detector provided at an associated motor, and a current control section to output a voltage command based on the current command outputted from said velocity control section and a current feedback value from a current detector for detecting a current of the associated motor, to operate a current amplifier in accordance with the voltage command; and

a damping controller to output a current command correction value for compensating an interference between the two motors based on the velocity feedback values from the velocity detectors for the two motors, said current command correction value being added to or subtracted from the current command in the position controller for one of the two motors and is subtracted from or added to the current command in the other position controller for the other of the two motors,

vibration applying/measuring means for generating a vibration application current command having a variable frequency and adding the vibration application current command to the current command in one of said position controllers so as to determine appropriateness of parameters of said damping controller based on a variation in the velocity feedback value from the velocity detector for one of the motors.

6. A servo controller according to claim 5, wherein said vibration applying/measuring means comprises a first means for generating a sine-sweep current command having a variable frequency, a second means for adding the sine-sweep current command to the current command in one of the position controller, and a third means for outputting the frequency of the sine-sweep current command and one of the velocity feedback values.

7. A servo controller according to claim 6, wherein said first means for generating the, sine-sweep current command varies the frequency thereof at every sampling period by multiplying the sampling period by a counting value increasing at every sampling period.

8. An apparatus, comprising:

a first motor with a first velocity detector and a second motor with a second velocity detector; and

a damping controller outputting a current command correction value for compensating an interference between the first motor and the second motor based on velocity feedback values from the first velocity detector and the second velocity detector,

wherein the current command correction value being added to a current command in a first position controller for the first motor and is subtracted from the current command in a second position controller for the second motor,

wherein the damping controller comprises a first computing unit integrating a deviation between the velocity feedback values from the velocity detectors associated with the two motors and multiplying the integrated value by a first constant, and second computing unit for multiplying the deviation of the velocity feedback values by a second constant, outputs of the first and second computing means being added together for use as the current command correction value.

9. An apparatus as recited in claim 8, wherein the damping controller further includes phase advancing/compensating means for advancing a phase of the current command correction value.

10. An apparatus, comprising:

a first motor with a first velocity detector and a second motor with a second velocity detector; and

a damping controller outputting a current command correction value for compensating an interference between the first motor and the second motor based on velocity feedback values from the first velocity detector and the second velocity detector,

wherein the current command correction value being added to a current command in a first position controller for the first motor and is subtracted from the current command in a second position controller for the second motor,

wherein the damping controller includes a computing unit integrating a deviation between the velocity feedback values from the velocity detectors associated with the two motors and multiplying the integrated value by a constant, an output of the computing unit being used as the current command correction value.

11. An apparatus, comprising:

a first motor with a first velocity detector and a second motor with a second velocity detector; and

a damping controller outputting a current command correction value for compensating an interference between the first motor and the second motor based on velocity feedback values from the first velocity detector and the second velocity detector,

wherein the current command correction value being added to a current command in a first position controller for the first motor and is subtracted from the current command in a second position controller for the second motor,

wherein the damping controller includes a computing unit multiplying a deviation between the velocity feedbacks values from the velocity detectors associated with the two motors by a constant, an output of the computing unit being used as the current command correction value.

12. An apparatus, comprising:

a first motor with a first velocity detector and a second motor with a second velocity detector; and

a damping controller outputting a current command correction value for compensating an interference between the first motor and the second motor based on velocity feedback values from the first velocity detector and the second velocity detector,

wherein the current command correction value being added to a current command in a first position controller for the first motor and is subtracted from the current command in a second position controller for the second motor,

a vibration applying/measuring unit generating a vibration application current command having a variable frequency and adding the vibration application current command to the current command in one of the position controllers to determine appropriateness of parameters of the damping controller based on a variation in the velocity feedback value from the velocity detector for one of the motors.

13. An apparatus as recited in claim 12, wherein the vibration applying/measuring unit comprises a first unit generating a sine-sweep current command having a variable frequency, a second unit adding the sine-sweep current command to the current command in one of the position controller, and a third unit outputting the frequency of the sine-sweep current command and one of the velocity feedback values.

14. A servo controller according to claim 13, wherein the first unit generating the sine-sweep current command varies the frequency thereof at every sampling period by multiplying the sampling period by a counting value increasing at every sampling period.

15. An apparatus, comprising:

a first motor with a first velocity detector and a second motor with a second velocity detector;

a damping controller outputting a current command correction value for compensating an interference between the first motor and the second motor based on velocity feedback values from the first velocity detector and the second velocity detector; and

a computing unit integrating a deviation between the velocity feedback values and multiplying the deviation by a first and/or second constant, wherein the output of the computing unit is used as a current command correction value.

16. An apparatus, comprising:

a first motor with a first velocity detector and a second motor with a second velocity detector;

a damping controller outputting a current command correction value for compensating an interference between the first motor and the second motor based on velocity feedback values from the first velocity detector and the second velocity detector; and

a vibration unit generating a vibration application current command having a variable frequency and adding the vibration application current command to the current command in one of the position controllers.