ROBOT, CONTROL DEVICE FOR ROBOT ARM AND CONTROL PROGRAM FOR ROBOT ARM

• US 20110218676A1
• Filed: 05/17/2011
• Published: 09/08/2011
• Est. Priority Date: 07/02/2009
• Status: Active Grant

• Current Assignee: Panasonic Corporation (Panasonic Holdings Corporation)
• Original Assignee: Panasonic Corporation (Panasonic Holdings Corporation)
• Inventors: OKAZAKI, Yasunao
• Granted Patent: US 8,185,243 B2
• Time in Patent Office: Days
• US Class Current: 700/260
• CPC Class Codes: B25J 15/0095 with an external support, i.e. a support which does not belong to the manipulator or the object to be gripped, e.g. for maintaining the gripping head in an accurate position, guiding it or preventing vibrations
• CPC Class Codes: B25J 9/1075 with muscles or tendons
• CPC Class Codes: B25J 9/142 comprising inflatable bodies
• CPC Class Codes: B25J 9/1612 characterised by the hand, wrist, grip control
• CPC Class Codes: B25J 9/1633 compliant, force, torque control, e.g. combined with position control
• CPC Class Codes: G05B 2219/39462 Pneumatic actuator, imitates human muscle

Abstract

A robot arm, which is driven by an elastic body actuator and has a plurality of joints, is provided with an arm-end supporting member that supports the robot arm when made in contact with a supporting surface that is placed on an arm-end portion of the robot arm and a control unit that controls a force by which the arm-end supporting member and the supporting surface are made in contact with each other, and further controls a position and orientation of the arm-end portion of the robot arm.

Claims

1. A robot comprising:

a robot arm that is driven by an elastic body actuator and has a plurality of joints;

an arm-end supporting member that is placed near a wrist portion of the robot arm on a base side from the wrist portion, and supports the arm-end portion of the robot arm by making in contact with a supporting surface of the robot arm; and

a control unit that controls a position and an orientation of the arm-end portion of the robot arm and controls a force by which the arm-end supporting member and the supporting surface are made in contact with each other, wherein

the control unit

(i) controls the force in a manner so as to press the arm-end supporting member onto the supporting surface to stop the position of the arm-end portion of the robot arm, and then controls the orientation of the arm-end portion, and

(ii) carries out a force control by using a pressing force that is smaller than the force controlled upon moving the orientation of the arm-end portion so that the position of the arm-end portion is shifted.

2. The robot according to claim 1, wherein the arm-end supporting member has at least two supporting legs that are expandable, and by controlling lengths of the at least two expandable supporting legs, the orientation of the arm-end portion of the robot arm is controlled.

3. The robot according to claim 1, wherein the arm-end supporting member is formed by an elastic sucker capable of being sucked or suction-released to and from the supporting surface by an air pressure, with friction between the sucker and the supporting surface being controllable.

4. The robot according to claim 1, wherein the arm-end supporting member is formed by an electromagnet capable of being sucked or suction-released to and from the supporting surface by a magnetic force, with friction between the electromagnet and the supporting surface being controlled.

5. The robot according to claim 1, wherein the arm-end supporting member is formed by a ball caster with a brake, with friction between the ball caster and the supporting surface being controlled.

6. The robot according to claim 1, wherein the arm-end supporting member is formed by a wheel with a brake, with friction between the wheel and the supporting surface being controlled separately depending on directions.

7. The robot according to claim 1, wherein the robot arm has three or more joints, and the arm-end supporting member is placed to a link of a second joint or thereafter from a fixed portion of the robot arm.

8. The robot according to claim 7, wherein the robot arm is further provided with a joint on an arm-end side from a position at which the arm-end supporting member is placed, with the joint having a degree of freedom that determines the orientation of the arm-end portion.

10. The robot according to claim 1, wherein, after supporting the arm-end portion of the robot arm by making the arm-end supporting member in contact with the supporting surface of the robot arm, the control unit controls the position and the orientation of the arm-end portion of the robot arm.

13. The robot according to claim 1, further comprising:

a desired trajectory generation unit that generates information relating to a position and an orientation of the arm-end portion for use in giving a control command relating to the position and the orientation of the arm-end portion to the control unit, wherein

the desired trajectory generation unit determines whether or not the orientation of the arm-end portion thus generated is located within a predetermined movable range, and gives a command for controlling the orientation of the arm-end portion to the control unit when the orientation of the arm-end portion thus generated is located within the predetermined movable range, and gives a command for controlling the position of the arm-end portion to the control unit when the orientation of the arm-end portion thus generated is located out of the predetermined movable range.

14. The robot according to claim 1, wherein, when the position of the arm-end portion of the robot arm is stopped and the orientation of the arm-end portion is moved, a force-controlling motion is carried out so as to press the arm-end supporting member onto the supporting surface, and a position controlling gain of the arm-end position in a case of moving the orientation of the arm-end portion is made lower than a position controlling gain of the arm-end position in a case other than the case of moving the orientation of the arm-end portion so that position controlling rigidity is lowered.

9. A robot comprising:

a robot arm that is driven by an elastic body actuator and has a plurality of joints;

an arm-end supporting member that is placed near a wrist portion of the robot arm on a base side from the wrist portion, and supports the arm-end portion of the robot arm by making in contact with a supporting surface of the robot arm; and

a control unit that controls a force by which the arm-end supporting member and the supporting surface are made in contact with each other, and further controls a position and an orientation of the arm-end portion of the robot arm, wherein

the control unit controls to decelerate an arm-end velocity of the robot arm by utilizing friction generated by the contact between the arm-end supporting member and the supporting surface.

11. A control device for a robot arm, which controls a robot arm that is driven by an elastic body actuator and has a plurality of joints, by making an arm-end supporting member that is placed near a wrist portion of the robot arm on a base side from the wrist portion in contact with a supporting surface so that the arm-end portion of the robot arm is supported, wherein

the control device

controls a position and an orientation of the arm-end portion of the robot arm and controls a force by which the arm-end supporting member and the supporting surface are made in contact with each other,

(i) controls the force in a manner so as to press the arm-end supporting member onto the supporting surface to stop the position of the arm-end portion of the robot arm, and then controls the orientation of the arm-end portion, and

(ii) carries out a force control by using a pressing force that is smaller than the force controlled upon moving the orientation of the arm-end portion so that the position of the arm-end portion is shifted.

12. A control program for a robot arm, which controls a robot arm that is driven by an elastic body actuator and has a plurality of joints, by making an arm-end supporting member that is placed near a wrist portion of the robot arm on a base side from the wrist portion in contact with a supporting surface so that the arm-end portion of the robot arm is supported, the control program causing a computer to:

controlling a position and an orientation of the arm-end portion of the robot arm, and controlling a force by which the arm-end supporting member and the supporting surface are made in contact with each other,

(i) controlling the force in a manner so as to press the arm-end supporting member onto the supporting surface to stop the position of the arm-end portion of the robot arm, and then controlling the orientation of the arm-end portion, and

(ii) carrying out a force control by using a pressing force that is smaller than the force controlled upon moving the orientation of the arm-end portion so that the position of the arm-end portion is shifted.