# US 11,114,967 B2 · Controller of rotary axis

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- Number: US 11,114,967 B2
- Document ID: US11114967B2
- Status: Granted
- Kind: B2
- Application number: 16/859,739
- Filed: 2020-04-27
- Published: 2020-12-03
- Granted: 2021-09-07
- Earliest claimed: 2019-05-30
- Assignees: Fanuc Corporation
- Applicants: Fanuc Corporation
- Inventors: Tarou Ogiso
- Web page: https://patentgrep.com/patent/US11114967B2

## CPC

- H02P 23/20: Controlling the acceleration or deceleration
- H02P 3/00: Arrangements for stopping or slowing electric motors, generators, or dynamo-electric converters (stopping of synchronous motors with electronic commutators H02P6/24; stopping dynamo-electric motors rotating step by step H02P8/24; vector control H02P21/00)
- H02P 2205/07: Speed loop, i.e. comparison of the motor speed with a speed reference
- H02P: CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS

## Abstract

A controller of a rotary axis includes: a storage unit that stores data of a braking distance for each rotation number of the rotary axis and provides a current braking distance S3 corresponding to a current rotation number of the rotary axis; and a deceleration command calculating unit that calculates a speed command V2 of the rotary axis on a basis of the remaining movement amount S2 and the current braking distance S3; in which the deceleration command calculating unit maintains the current rotation number of the rotary axis in a case in which a difference S4 between the remaining movement amount S2 and the current braking distance S3 is equal to or greater than a predetermined value, and starts deceleration of the rotary axis in a case in which the difference S4 is less than the predetermined value.

## Claims

### Claim 1

A controller of a rotary axis that decelerates the rotary axis to a predetermined speed at a predetermined position, the controller comprising:
a total movement command calculating unit that calculates a remaining movement amount S2 by subtracting a movement command M1 for each control cycle in every control cycle from a total movement amount S1 from a current position until the predetermined position, in a case in which a positioning request to decelerate the rotary axis to the predetermined speed at the predetermined position is issued;
a movement command calculating unit that calculates the movement command M1 for each control cycle from the remaining movement amount S2;
a storage unit that stores in advance data of a braking distance for each rotation number of the rotary axis, the data of the braking distance being based on a maximum torque characteristic with respect to a rotation number of a motor for driving the rotary axis, refers to the data of the braking distance, and provides a current braking distance S3 corresponding to a current rotation number of the rotary axis;
a deceleration command calculating unit that calculates a speed command V2 of the rotary axis on a basis of the remaining movement amount S2 and the current braking distance S3; and
a speed control unit that causes a speed of the motor to follow the speed command V2,
wherein the deceleration command calculating unit
calculates the speed command V2 to maintain the current rotation number of the rotary axis in a case in which a difference S4 between the remaining movement amount S2 and the current braking distance S3 is equal to or greater than a predetermined value, and
calculates the speed command V2 to start deceleration of the rotary axis in a case in which the difference S4 is less than the predetermined value.

### Claim 2 (depends on 1)

The controller of the rotary axis according to claim 1, wherein the data of the braking distance is set larger than a braking distance based on the maximum torque characteristic of the motor, and
the deceleration command calculating unit
calculates the speed command V2 to perform full torque deceleration by a maximum acceleration based on the maximum torque characteristic of the motor, in a case in which the difference S4 is equal to or less than zero, and
calculates the speed command V2 to make acceleration weaker than the full torque deceleration, in a case in which the difference S4 is greater than zero and less than the predetermined value.

### Claim 3 (depends on 2)

The controller of the rotary axis according to claim 2, wherein the deceleration command calculating unit sequentially adjusts acceleration of deceleration of the rotary axis in a case in which the difference S4 is greater than zero and less than the predetermined value after a start of the deceleration.

### Claim 4 (depends on 1)

The controller of the rotary axis according to claim 1, wherein the deceleration command calculating unit performs acceleration of the rotary axis at acceleration based on the maximum torque characteristic of the motor, in a case in which the current rotation number of the rotary axis is equal to or less than a second predetermined value.

### Claim 5 (depends on 4)

The controller of the rotary axis according to claim 4, wherein the deceleration command calculating unit performs acceleration of the rotary axis up to an upper limit value of the rotation number of the rotary axis.

### Claim 6 (depends on 1)

The controller of the rotary axis according to claim 1, wherein the deceleration command calculating unit performs deceleration of the rotary axis at acceleration based on the maximum torque characteristic of the motor up to a rotation number corresponding to a braking distance present in the data of the braking distance, in a case in which a braking distance corresponding to the current rotation number of the rotary axis in the data of the braking distance.

### Claim 7 (depends on 6)

The controller of the rotary axis according to claim 6, wherein the storage unit updates the data of the braking distance to follow a braking distance based on a maximum torque characteristic with respect to a rotation number in the deceleration of the rotary axis.

### Claim 8 (depends on 1)

The controller of the rotary axis according to claim 1, further comprising: a position control unit that calculates a speed command V1 on a basis of the movement command M1; and
a speed command selecting unit that selects either one of the speed command V1 or the speed command V2 and provides to the speed control unit,
wherein the speed command selecting unit
selects the speed command V2 when the positioning request is issued, and
subsequently selects the speed command V1 for which the acceleration based on the maximum torque characteristic of the motor becomes constant, in a case in which the rotation number of the rotary axis is equal to or less than a base rotation number of the motor, and being a phase matching completion state in which the difference S4 between the remaining movement amount S2 and the current braking distance S3 is zero.