Servomotor control device, servomotor control method, and computer-readable recording medium

• US 10,162,332 B2
• Filed: 09/06/2017
• Issued: 12/25/2018
• Est. Priority Date: 09/08/2016
• Status: Active Grant

• Current Assignee: Fanuc Corporation
• Original Assignee: Fanuc Corporation
• Inventors: Shinoda, Shougo, Ikai, Satoshi
• Primary Examiner(s): Ali, Mohammad
• Assistant Examiner(s): Kabir, Saad M
• Application Number:
  US15/696,681
• Publication Number:
  US 20180067469A1
• Time in Patent Office: 475 Days
• Field of Search: None
• CPC Class Codes: G05B 19/404 characterised by control arrangements for compensation, e.g. for backlash, overshoot, tool offset, tool wear, temperature, machine construction errors, load, inertia G05B19/19, G05B19/41 take precedence
• CPC Class Codes: G05B 2219/39177 Compensation position working point as function of inclination tool, hand
• CPC Class Codes: G05B 2219/39188 Torque compensation

Abstract

A servomotor control device includes a servomotor; a driven body configured to be driven by the servomotor; a connection mechanism configured to connect the servomotor and driven body, and transmit power of the servomotor to the driven body; a position command generation unit configured to generate a position command value; a motor control unit configured to control the servomotor using the position command value; a position command compensation unit including a force estimation part configured to estimate a drive force acting on the driven body at the connection mechanism, and a compensation amount generation part configured to generate a compensation amount for compensating the position command value based on the estimated drive force; and a restriction part configured to restricting updating of the compensation amount when a command acceleration or a command velocity of the position command value is no more than a desired value.

Claims

1. A servomotor control device, comprising:

a servomotor;

a driven body configured to be driven by the servomotor;

a connection mechanism configured to connect the servomotor and the driven body, and transmit power of the servomotor to the driven body;

a position command generation unit configured to generate a position command value for the driven body;

a motor control unit configured to control the servomotor using the position command value; and

a position command compensation unit including a force estimation part configured to estimate a drive force acting on the driven body at a connecting part with the connection mechanism, and a compensation amount generation part configured to generate a compensation amount for compensating the position command value generated by the position command generation unit, based on a drive force estimated by the force estimation part,

wherein the position command compensation unit includes a restriction part configured to restrict updating of the compensation amount, when a command acceleration of the position command value is no more than a desired value, or when a command velocity of the position command value is no more than a desired value.

2. The servomotor control device according to claim 1, wherein restriction of the updating of the compensation amount by the restriction part interrupts updating in which the magnitude of the compensation amount increases.

3. The servomotor control device according to claim 1, wherein restriction of the updating of the compensation amount by the restriction part interrupts the updating of the compensation amount.

4. The servomotor control device according to claim 1, wherein the restriction part includes a filter configured to suppress a change from a compensation amount that was restricted, to a compensation amount after updating, when restarting the updating of the compensation amount.

5. The servomotor control device according to claim 1,

wherein the motor control unit includes a velocity command creation part and a torque command creation part,

wherein the torque command creation part includes at least an integrator that integrates a speed deviation, and

wherein the restriction part performs overwriting of the integrator when restarting the updating of the compensation amount.

6. A servomotor control method for controlling a servomotor in a servomotor control device including the servomotor;

a driven body configured to be driven by the servomotor; and

a connection mechanism configured to connect the servomotor and the driven body, and transmit power of the servomotor to the driven body, the method comprising the steps of;

generating a position command value for the driven body;

estimating drive force acting on the driven body at a connecting part with the connection mechanism;

generating a compensation amount for compensating the position command value based on the drive force thus estimated;

restricting updating of the compensation amount when a command acceleration of the position command value is no more than a desired value, or when a command velocity of the position command value is no more than a desired value; and

controlling the servomotor using the position command value for which updating was restricted.

7. The servomotor control method according to claim 6, wherein restricting of the updating of the compensation amount is interrupting updating in which the magnitude of the compensation amount increases.

8. The servomotor control method according to claim 6, wherein restricting of the updating of the compensation amount is interrupting the updating of the compensation amount.

9. The servomotor control method according to claim 6, further comprising a step of suppressing, by way of a filter, a change from a compensation amount that was restricted, to a compensation amount after updating, when restarting the updating of the compensation amount.

10. The servomotor control method according to claim 6, further comprising the steps of:

creating a velocity command using the position command value in which updating was restricted, creating a torque command using the velocity command thus created, and controlling the servomotor using the torque command, wherein the creating of the torque command is performed using an integrator that at least integrates a speed deviation; and

performing overwriting of the integrator when restarting the updating of the compensation amount.

11. A non-transitory computer-readable recording medium encoded with a servomotor control program which enables a computer to execute servomotor control in a servomotor control device that includes a servomotor,

a driven body configured to be driven by the servomotor, and

a connection mechanism configured to connect the servomotor and the driven body, and transmit power of the servomotor to the driven body, the program causing the computer to execute processing of:

generating a position command value for the driven body;

estimating drive force acting on the driven body at a connecting part with the connection mechanism;

generating a compensation amount for compensating the position command value based on the drive force thus estimated;

restricting updating of the compensation amount when a command acceleration of the position command value is no more than a desired value, or when a command velocity of the position command value is no more than a desired value; and

controlling the servomotor using the position command value for which updating was restricted.