Control Apparatus And Robot System

• US 20200130200A1
• Filed: 10/29/2019
• Published: 04/30/2020
• Est. Priority Date: 10/30/2018
• Status: Active Grant

• Current Assignee: Seiko Epson Corporation (Seiko Group)
• Original Assignee: Seiko Epson Corporation (Seiko Group)
• Inventors: ADACHI, Hiroki, MOTOYOSHI, Masaki
• Granted Patent: US 11,173,614 B2
• Time in Patent Office: Days
• CPC Class Codes: B25J 13/085 Force or torque sensors B25J13/082, B25J13/084 take precedence
• CPC Class Codes: B25J 9/163 learning, adaptive, model based, rule based expert control
• CPC Class Codes: B25J 9/1666 Avoiding collision or forbidden zones
• CPC Class Codes: 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
• CPC Class Codes: G05B 2219/36429 Power assisted positioning
• CPC Class Codes: G05B 2219/36473 Prohibit teaching if force, speed, acceleration of end effector is out of safe range
• CPC Class Codes: G05B 2219/39082 Collision, real time collision avoidance
• CPC Class Codes: G05B 2219/40582 Force sensor in robot fixture, base

Abstract

When a first condition that a time in which magnitude of a first detection force detected by a force detection unit is larger than a first force threshold value continued for a time longer than zero and shorter than a first time threshold value is satisfied in teaching, a movable unit is moved in a predetermined amount in a direction according to a direction of the first detection force. When a second condition that magnitude of a second detection force detected by the force detection unit is larger than a second force threshold value that is larger than the first force threshold value is satisfied during movement of an end effector, the movable unit is decelerated or stopped.

Claims

1. A robot system comprising:

a robot having a base, a movable unit provided movably relative to the base, and a force detection unit that detects a force applied to the movable unit; and

a control unit that controls the movable unit according to the force detected by the force detection unit in teaching of the robot, wherein

when a first condition that a time in which magnitude of a first detection force detected by the force detection unit is larger than a first force threshold value continued for a time longer than zero and shorter than a first time threshold value is satisfied in the teaching, the control unit moves the movable unit in a predetermined amount in a direction according to a direction of the first detection force, and

when a second condition that magnitude of a second detection force detected by the force detection unit is larger than a second force threshold value that is larger than the first force threshold value is satisfied during the movement of the movable unit, the control unit decelerates or stops the movable unit.

2. The robot system according to claim 1, wherein

when a third condition that a time in which the magnitude of the first detection force is larger than a third force threshold value that is smaller than the first force threshold value continued for a duration longer than a second time threshold value is satisfied in the teaching, the control unit repeatedly executes the movement of the movable unit in the predetermined amount in the direction according to the direction of the first detection force during the duration.

3. The robot system according to claim 2, wherein

the control unit repeatedly determines whether or not the first condition or the third condition is satisfied in a first period in the teaching and repeatedly determines whether or not the second condition is satisfied in a second period during the movement of the movable unit, and

the first period is longer than the second period.

4. The robot system according to claim 2, wherein

the force detection unit includes a force detection unit having a piezoelectric element,

the control unit repeatedly executes the movement of the movable unit in the predetermined amount in the direction according to the direction of the first detection force in the duration based on output of the force detection unit having the piezoelectric element, and

the third force threshold value is larger than 1 N and smaller than 10 N.

5. The robot system according to claim 1, wherein

the force detection unit includes a first force detection unit provided in the base.

6. The robot system according to claim 5, wherein

the control unit judges the first condition based on output of the first force detection unit in the teaching, and judges the second condition based on the output of the first force detection unit during the movement of the movable unit.

7. The robot system according to claim 5, wherein

the force detection unit includes an end effector provided in the movable unit and a second force detection unit provided between the movable unit and itself.

8. The robot system according to claim 7, wherein

the control unit judges the first condition based on output of the second force detection unit in the teaching, and judges the second condition based on the output of the first force detection unit during the movement of the movable unit.

9. A control apparatus that, in teaching of a robot having a base, a movable unit provided movably relative to the base, and a force detection unit that detects a force applied to the movable unit, controls the movable unit according to the force detected by the force detection unit,

when a first condition that a time in which magnitude of a first detection force detected by the force detection unit is larger than a first force threshold value continued for a time longer than zero and shorter than a first time threshold value is satisfied in the teaching, moving the movable unit in a predetermined amount in a direction according to a direction of the first detection force, and

when a second condition that magnitude of a second detection force detected by the force detection unit is larger than a second force threshold value that is larger than the first force threshold value is satisfied during the movement of the movable unit, decelerating or stopping the movable unit.

10. A robot teaching control method for causing a processor to execute a process, the method comprising executing on the processor the steps of:

detecting a first detection force or a second detection force applied to an arm of a robot by a force sensor, the robot having a base, the base being provided at the arm, the force sensor being provided at the arm;

determining whether a first condition is satisfied, the first condition being that a time in which magnitude of the first detection force is larger than a first force threshold value continued for a time longer than zero and shorter than a first time threshold value;

moving the arm in a direction according to a direction of the first detection force in a predetermined amount in response to a determination of the first condition;

determining whether a second condition is satisfied, the second condition being that a magnitude of the second detection force is larger than a second force threshold value that is larger than the first force threshold value during the movement of the arm; and

decelerating or stopping the arm in response to a determination of the second condition.