Robot system and method for producing to-be-processed material

• US 9,908,160 B2
• Filed: 10/31/2014
• Issued: 03/06/2018
• Est. Priority Date: 11/01/2013
• Status: Active Grant

• Current Assignee: Kabushiki Kaisha Yaskawa Denki
• Original Assignee: Kabushiki Kaisha Yaskawa Denki
• Inventors: Okahisa, Manabu, Nakakura, Masami, Sonoda, Teppei
• Primary Examiner(s): Vo, Peter DungBa
• Assistant Examiner(s): Anderson, Joshua D
• Application Number:
  US14/529,209
• Publication Number:
  US 20150121983A1
• Time in Patent Office: 1,222 Days
• Field of Search: 72210, 72214, 72220
• CPC Class Codes: B21B 31/16 Adjusting or positioning rolls control devices B21B37/00
• CPC Class Codes: B21B 37/58 Roll-force control; Roll-gap control B21B38/105 takes precedence
• CPC Class Codes: B21D 19/043 for flanging edges of plates
• CPC Class Codes: B21D 39/021 for panels, e.g. vehicle doors
• CPC Class Codes: B21D 39/023 using rollers
• CPC Class Codes: B21D 5/16 Folding; Pleating
• CPC Class Codes: B25J 9/1633 compliant, force, torque control, e.g. combined with position control
• CPC Class Codes: B25J 9/1679 characterised by the tasks executed
• CPC Class Codes: G05B 2219/39329 Adaptive force and position control
• CPC Class Codes: G05B 2219/40052 Deform, bend flexible material
• CPC Class Codes: Y10S 901/02 Arm motion controller
• CPC Class Codes: Y10S 901/15 Jointed arm
• CPC Class Codes: Y10S 901/41 Tool
• CPC Class Codes: Y10T 29/49908 Joining by deforming

Abstract

A robot system includes an end effector, a robot arm, and a controller. The end effector includes a pressure roller and a linear motion mechanism. The linear motion mechanism is configured to move the pressure roller with respect to a pressed surface. The robot arm is configured to support the end effector. The controller is configured to control the linear motion mechanism to move the pressure roller to make a pressing force of the pressure roller against the pressed surface approximately uniform.

Claims

1. A robot system comprising:

an end effector comprising;

a pressure roller that forms a distal end of the end effector; and

a linear motion mechanism configured to move the pressure roller with respect to a pressed surface and change a stroke position of the pressure roller as an amount by which the pressure roller protrudes from a central portion of the end effector;

a robot arm configured to support the end effector; and

a controller configured to control the linear motion mechanism to move the pressure roller to make a pressing force of the pressure roller against the pressed surface approximately uniform during a torque control during which the controller is configured to set a torque of a motor configured to drive the linear motion mechanism into linear motion at a predetermined torque, configured to switch from the torque control to a position control during which the controller is configured to control the stroke position of the pressure roller, and configured to drive the linear motion mechanism when the robot arm is deflected by a reaction force that opposes the pressing force.

2. The robot system according to claim 1, wherein the linear motion mechanism is configured to move the pressure roller up and down with respect to the pressed surface.

3. The robot system according to claim 2, wherein the controller is configured to change the pressing force in accordance with at least one of a shape and a property of the pressed surface.

4. The robot system according to claim 2, wherein the pressed surface comprises a hemming surface subjected to bending processing by the pressure roller.

5. The robot system according to claim 1, wherein the motor comprises a servomotor.

6. The robot system according to claim 5, wherein the controller is configured to change the pressing force in accordance with at least one of a shape and a property of the pressed surface.

7. The robot system according to claim 5, further comprising a program storage configured to store a program defining a motion path of the robot arm,

wherein the controller comprises a program editor configured to receive in the program a setting of starting operation control of the linear motion mechanism of the end effector, and configured to receive in the program a setting of ending the operation control of the linear motion mechanism of the end effector.

8. The robot system according to claim 7, wherein the program editor is configured to, at a desired timing in the program, define a command to control the torque of the servomotor during the torque control and a command to control the stroke position of the linear motion mechanism during the position control.

9. The robot system according to claim 5, wherein the controller is configured to hold the distance constant during the position control.

10. The robot system according to claim 1, wherein the controller is configured to maintain the stroke position at a predetermined position during the position control.

11. The robot system according to claim 10, wherein the controller is configured to change the pressing force in accordance with at least one of a shape and a property of the pressed surface.

12. The robot system according to claim 1, wherein the pressed surface comprises a hemming surface subjected to bending processing by the pressure roller.

13. The robot system according to claim 12, wherein the controller is configured to change the pressing force in accordance with at least one of a shape and a property of the pressed surface.

14. The robot system according to claim 1,

wherein the robot arm comprises a plurality of joints, and

wherein the controller comprises an inverse kinematics calculator configured to control rotation positions of the plurality of joints based on a motion path of the robot arm taught in advance.

15. The robot system according to claim 14, wherein the controller is configured to change the pressing force in accordance with at least one of a shape and a property of the pressed surface.

16. The robot system according to claim 1, wherein the controller is configured to change the pressing force in accordance with at least one of a shape and a property of the pressed surface.

17. The robot system according to claim 1, wherein the pressure roller rotates about an axis, the axis being spaced away from the central portion of the end effector, a distance by which the axis is spaced away from the central portion of the end effector being changeable by the linear motion mechanism.

18. The robot system according to claim 1, further comprising a linear motion shaft which is directly coupled to the pressure roller, the position of the linear motion shaft being movable with the pressure roller to change a distance between the linear motion shaft and the central portion of the end effector.

19. The robot system according to claim 1,

wherein the robot arm comprises a flange to which the end effector is mounted, and

wherein the linear motion mechanism is configured to change a position of the distal end of the end effector relative to the flange.

20. The robot system according to claim 1, further comprising:

the motor comprises a servomotor configured to drive the linear motion mechanism into linear motion, the servomotor including a position detector, and

wherein the controller is configured to monitor the stroke position based on the position detector.

21. The robot system according to claim 1, wherein the controller is configured to switch to the position control in a case where the pressed surface is susceptible to elastic deformation.

22. The method according to claim 1, wherein the controller is configured to switch from the torque control to the position control at a predetermined position relative to the pressed surface.

23. A method for producing a to-be-processed material, the method comprising:

operating a robot arm configured to support an end effector, the end effector comprising a pressure roller that forms a distal end of the end effector and a linear motion mechanism, the linear motion mechanism being configured to move the pressure roller up and down with respect to a pressed surface and change a stroke position of the pressure roller as an amount by which the pressure roller protrudes from a central portion of the end effector;

controlling the linear motion mechanism to move the pressure roller up and down so as to make a pressing force of the pressure roller against the pressed surface approximately uniform during a torque control during which a torque of a motor configured to drive the linear motion mechanism into linear motion is set at a predetermined torque;

driving the linear motion mechanism when the robot arm is deflected by a reaction force that opposes the pressing force; and

switching from the torque control to a position control during which the stroke position of the pressure roller is controlled.

24. The method according to claim 23, further comprising switching to the position control in a case where the pressed surface is susceptible to elastic deformation.

25. The method according to claim 23, further comprising holding the stroke position constant during the position control.

26. The method according to claim 23, wherein the switching from the torque control to the position control is performed at a predetermined position relative to the pressed surface.

27. A robot system comprising:

an end effector comprising;

a pressure roller that forms a distal end of the end effector; and

a linear motion mechanism configured to move the pressure roller with respect to a pressed surface and change a stroke position of the pressure roller as an amount by which the pressure roller protrudes from a central portion of the end effector;

a robot arm configured to support the end effector; and

a controller configured to control the linear motion mechanism to move the pressure roller to make a pressing force of the pressure roller against the pressed surface approximately uniform during a torque control during which the controller is configured to set a torque of a motor configured to drive the linear motion mechanism into linear motion at a predetermined torque,

wherein the pressed surface includes a corner portion and a side portion spaced from the corner portion, and

wherein the controller is configured to switch from the torque control to a position control and adjust the stroke position at the corner portion during the position control and maintain the stroke position at a predetermined position at the side portion during the position control.