# US 11,305,423 B2 · Control device for robot having arm

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- Number: US 11,305,423 B2
- Document ID: US11305423B2
- Status: Granted
- Kind: B2
- Application number: 17/005,722
- Filed: 2020-08-28
- Published: 2021-03-04
- Granted: 2022-04-19
- Earliest claimed: 2019-09-03
- Assignees: Fanuc Corporation
- Applicants: Fanuc Corporation
- Inventors: Yuuya Iwase
- Web page: https://patentgrep.com/patent/US11305423B2

## CPC

- B25J 9/1633: {compliant, force, torque control, e.g. combined with position control}
- B25J 9/0081: {with leader teach-in means}
- B25J 13/085: {Force or torque sensors (B25J13/082, B25J13/084 take precedence)}
- G05B 19/423: Teaching successive positions by walk-through, i.e. the tool head or end effector being grasped and guided directly, with or without servo-assistance, to follow a path
- B25J: MANIPULATORS; CHAMBERS PROVIDED WITH MANIPULATION DEVICES ({manipulators specially adapted for use in surgery A61B34/70; manipulators used in cleaning hollow articles B08B9/04}; manipulators associated with rolling mills B21B39/20; manipulators associated with forging machines B21J13/10; {manipulators associated with picking-up and placing mechanisms B23P19/007}; means for holding wheels or parts thereof B60B30/00; {vehicles with ground-engaging propulsion means, e.g. walking members B62D57/02, B62D57/032; devices for picking-up and depositing articles or materials between conveyors B65G47/90, B65G47/91; manipulators with gripping or holding means for transferring packages B65H67/065}; cranes B66C; {manipulators used in the protection or supervision of pipe-line installations F17D5/00; walking equipment adapted for nuclear steam-generators F22B37/006}; manipulators specially adapted for, or associated with, nuclear reactors G21C; {apparatus used for handling wafers during manufacture or treatment of semiconductor H10P72/50})
- 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

To provide a control device of a robot having an arm which causes the arm to be stopped more easily than conventionally by generating a load of appropriate magnitude to an operator during lead-through. The present invention relates to a control device of a robot having an arm, the control device including: a motor that generates torque in each axis of the robot; a torque generation control unit that controls the motor so as to generate a canceling torque which cancels friction of each axis of the robot when controlling the robot by external force tracking; and a torque changing unit that changes the canceling torque to a reference value or less.

## Claims

### Claim 1

A control device of a robot having an arm, the control device comprising:
a motor that generates torque in each axis of the robot;
a torque generation control unit that controls the motor so as to generate a canceling torque which cancels friction of each axis of the robot when controlling the robot by external force tracking; and
a torque changing unit that changes the canceling torque to a reference value or less.

### Claim 2 (depends on 1)

The control device according to claim 1, wherein the torque changing unit changes the canceling torque based on a speed feedback value from the motor, or an estimated value of a force applied by a user to the arm.

### Claim 3 (depends on 2)

The control device according to claim 2, wherein, in a case in which the speed feedback value or the estimated value is a first threshold value or less, the torque changing unit changes the canceling torque to a value between zero or more and a second threshold value or less, and in a case in which the speed feedback value or the estimated value is a third threshold value which is greater than the first threshold value or more, the torque changing unit changes the canceling torque to a value between zero or more and a fourth threshold value which is greater than the second threshold value or less.

### Claim 4 (depends on 2)

The control device according to claim 2, wherein, in a case in which a distance between a boundary of an operable area of the arm and a center point of a tip end portion of the arm is a fifth threshold value or less, the torque changing unit changes the canceling torque so that the distance and a gain used for changing the canceling torque have a positive correlation, and sets the gain to zero when the distance is zero.