# US 10,101,729 B2 · Motor control device, motor control method and computer readable recording medium

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- Number: US 10,101,729 B2
- Document ID: US10101729B2
- Status: Granted
- Kind: B2
- Application number: 15/679,584
- Filed: 2017-08-17
- Published: 2018-02-22
- Granted: 2018-10-16
- Earliest claimed: 2016-08-22
- Assignees: Fanuc Corporation
- Applicants: Fanuc Corporation
- Inventors: Tsutomu Nakamura; Satoshi Ikai
- Web page: https://patentgrep.com/patent/US10101729B2

## CPC

- G05B 19/4163: {Adaptive control of feed or cutting velocity (without NC B23Q15/12)}
- G05B 11/011: {details of the correcting means}
- 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
- G05B 2219/41: Servomotor, servo controller till figures
- G05B 2219/43117: Torque compensation as function of position reference, feedback of speed and position
- G05B: CONTROL OR REGULATING SYSTEMS IN GENERAL; FUNCTIONAL ELEMENTS OF SUCH SYSTEMS; MONITORING OR TESTING ARRANGEMENTS FOR SUCH SYSTEMS OR ELEMENTS (systems for controlling or regulating non-electric variables G05D; systems for regulating electric or magnetic variables G05F; control devices or systems insofar as characterised by mechanical features only G05G)

## Abstract

A motor control device includes a velocity controller configured to calculate a torque command from a velocity command and a motor velocity; a compensation torque calculation unit configured to calculate a compensation torque command by multiplying an error between the motor velocity and a velocity of a driven part by a compensation gain and a compensation filter; a torque control unit configured to control torque of a motor based on a value obtained by adding the torque command and the compensation torque command; and a setting change part configured to change a gain of the velocity controller according to an operating condition of the motor control device, and change at least one of the compensation gain and the compensation filter in accordance with a change in the gain of the velocity controller.

## Claims

### Claim 1

A motor control device for a motor coupled with a driven part of a machine via an elastically deformable element, comprising:
a velocity command part configured to generate a velocity command;
a first velocity detector configured to detect a motor velocity of the motor;
a second velocity detector configured to detect a velocity of the driven part;
a velocity controller configured to calculate a torque command from the velocity command and the motor velocity;
a compensation torque calculation unit configured to calculate a compensation torque command by multiplying an error between the motor velocity and the velocity of the driven part by a compensation gain and compensation filter;
a torque control unit configured to control torque of the motor based on a value arrived at by adding the torque command and the compensation torque command; and
a setting change part configured to change a gain of the velocity controller according to an operating condition of the motor control device, and change at least one of the compensation gain and the compensation filter in accordance with a change in the gain of the velocity controller.

### Claim 2 (depends on 1)

The motor control device according to claim 1, wherein the setting change part multiples a transfer characteristic of the velocity controller by F(s), a transfer function of Laplace operator s, according to the change in the gain of the velocity controller performed in response to the operating condition of the motor control device, and multiples the compensation filter of the compensation torque calculation unit by F(s).

### Claim 3 (depends on 1)

The motor control device according to claim 1,
wherein the velocity controller multiples a transfer characteristic by F(s), a transfer function of Laplace operator s, according to the change in the gain performed in response to the operating condition of the motor control device, and
wherein the compensation torque calculation unit multiples the compensation gain by |F(jω)|, a magnification of F(s) where Laplace operator s equals to jω, according to an angular frequency ω designated in advance.

### Claim 4 (depends on 3)

The motor control device according to claim 3, wherein a change in the transfer characteristic of the velocity controller is a constant A.

### Claim 5 (depends on 1)

The motor control device according to claim 1, wherein the compensation torque calculation unit decreases the compensation gain, when causing gain of the velocity controller to change in response to the operating condition of the motor control device.

### Claim 6 (depends on 1)

The motor control device according to claim 1, wherein the operating condition of the motor control device is either cutting feed or rapid traverse of the driven part.

### Claim 7

A motor control method for a motor control device of a motor coupled with a driven part of a machine via an elastically deformable element, the method comprising:
generating a velocity command;
calculating a torque command by a velocity controller based on a difference between the velocity command and a velocity of the driven part, the velocity of the driven part being detected by a second velocity detector;
calculating a compensation torque command by multiplying error between motor velocity of the motor and the velocity of the driven part by a compensation gain and compensation filter, the motor velocity of the motor being detected by a first velocity detector;
controlling torque of the motor based on a value obtained by adding the torque command and the compensation torque command; and
changing the gain of the velocity controller in response to the operating condition of the motor control device, and changing at least one among the compensation gain and the compensation filter in accordance with the change in the gain of the velocity controller.

### Claim 8 (depends on 7)

The motor control method according to claim 7, wherein a transfer characteristic of the velocity controller is multiplied by F(s), a transfer function of Laplace operator s, according to the change in the gain of the velocity controller performed in response to the operating condition of the motor control device, and the compensation filter is multiplied by F(s).

### Claim 9 (depends on 7)

The motor control method according to claim 7, wherein the velocity controller multiples a transfer characteristic by F(s), a transfer function of Laplace operator s, according to the change in the gain performed in response to the operating condition of the motor control device, and
wherein the compensation gain is multiplied by |F(jω)|, a magnification of F(s) where Laplace operator s equals to jω, according to an angular frequency ω designated in advance.

### Claim 10 (depends on 9)

The motor control method according to claim 9, wherein a change in the transfer characteristic of the velocity controller is a constant A.

### Claim 11 (depends on 7)

The motor control method according to claim 7, wherein the method decreases the compensation gain when causing the gain of the velocity controller to change in response to the operating condition of the motor control device.

### Claim 12 (depends on 7)

The motor control method according to claim 7, wherein the operating condition of the motor control device is either cutting feed or rapid traverse of the drive part.

### Claim 13

A non-transitory computer-readable recording medium encoded with a motor control program enabling a computer serving as a motor control device of a motor coupled to a driven part of a machine via an elastically deformable element to execute:
processing of generating a velocity command;
processing of calculating a torque command by way of a velocity controller based on the velocity command and a velocity of the driven part, the velocity of the driven part being detected by a second velocity detector;
processing of calculating a compensation torque command by multiplying error between a motor velocity of the motor and the velocity of the driven part by a compensation gain and a compensation filter, the motor velocity of the motor being detected by a first velocity detector;
processing of controlling torque of the motor based on a value obtained by adding the torque command and the compensation torque command; and
processing of changing the gain of the velocity controller in response to the operating condition of the motor control device, and changing at least, one among the compensation gain and the compensation filter in accordance with the change in the gain of the velocity controller.