Robot system

• US 4,906,907 A
• Filed: 03/30/1988
• Issued: 03/06/1990
• Est. Priority Date: 03/30/1987
• Status: Expired due to Term

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Takarada, Shinichi, Tsuchihashi, Akira
• Primary Examiner(s): Shoop, Jr., William M.
• Assistant Examiner(s): Ip, Paul
• Application Number:
  US07/175,318
• Time in Patent Office: 706 Days
• Field of Search: 318/562-577, 901/1, 901/9, 901/14, 901/15, 901/16, 901/17, 901/18, 901/19, 901/21, 901/23, 901/24, 901/30-34, 901/38, 901/46, 364/513, 414/739, 414/740
• US Class Current: 318/568.22
• CPC Class Codes: B25J 13/08 by means of sensing devices, e.g. viewing or touching devices
• CPC Class Codes: B25J 13/085 Force or torque sensors B25J13/082, B25J13/084 take precedence
• CPC Class Codes: B25J 13/088 with position, velocity or acceleration sensors
• CPC Class Codes: B25J 19/023 including video camera means
• CPC Class Codes: B25J 9/06 characterised by multi-articulated arms
• CPC Class Codes: B25J 9/1638 compensation for arm bending/inertia, pay load weight/inertia
• CPC Class Codes: B64G 4/00 Tools specially adapted for use in space

Abstract

A robot system in which a force (torque) exerted on an end effector disposed at an end of a robot to hold an object is sensed to achieve a positioning control. The robot system includes a unit to sense an inertial force exerted on the end effector and the sensed result is fed back so as to remove the influence of the inertia force, thereby effecting an accurate positioning control.

Claims

1. A robot system comprising:

a robot having at least a joint therein;

joint drive means for driving said joint in said robot;

hold means disposed at an end of said robot for holding an object;

actuation means for actuating said hold means;

sense means for sensing a force (torque) exerted on said hold means;

second sense means for sensing an inertia force exerted on said hold means; and

means responsive to the sensed results from said first and second sense means for determining a corrected external force by subtraction a sensed inertia force exerted on the object held by the hold means from the force sensed by said first sense means and controlling said joint drive means depending on said determined corrected external force.

2. A robot system according to claim 1 wherein said second sense means is comprised of an acceleration sensor.

3. A robot system according to claim 1 wherein said second sense means comprises:

image detection means for detecting a movement of said hold means, and

image processor for analyzing an output image from said image detection means.

4. A robot system according to claim 1 wherein said second sense means comprises:

position detectors for detecting positions of said joints of said robot, and

an arithmetic unit for effecting an arithmetic process on detected signals from said position detectors.

5. A robot system according to claim 1 wherein said first sense means and said second sense means are integrated in a single unit and said unit is connected between said robot and said hold means.

6. A robot system according to claim 1 wherein said control means includes:

means for generating drive target values of said joint drive means depending on the sensed result from said first sense means, and

means for correcting the drive target values depending on the sensed result from said second sense means so that the inertia force exerted on said object is removed from said force sensed by said first sense means.

7. A robot system comprising:

a robot having at least a joint therein;

joint drive means for driving said robot;

means disposed at an end of said robot for holding an object;

actuator means for actuating said hold means;

first sense means for sensing a force (torque) exerted on said hold means;

sense means for sensing an inertia force effected on said hold means;

third sense means for sensing an inertia force exerted on said robot; and

means for controlling said joint drive means depending on sensed results from said first, second, and third sense means.

8. A robot system according to claim 7 wherein said second sense means is comprised of an acceleration sensor.

9. A robot system according to claim 7 wherein said second sense means comprises:

image detection means for detecting a movement of said hold means, and

an image processor for analyzing an output image from said image detection means.

10. A robot system according to claim 7 wherein said second sense means comprises:

position detectors for detecting positions of said joints of said robot, and

an arithmetic unit for effecting an arithmetic process on detected signals from said position detectors.

11. A robot system according to claim 7 wherein said first sense means and said second sense means are integrally arranged in a unit so as to be connected between said robot and said hold means.

12. A robot system according to claim 7 wherein said third sense means is connected between a base securing said robot and a root portion of said robot.

13. A robot system according to claim 7 wherein said control means includes;

means for generating drive target values of said joint drive means depending on the sensed result from said first sense means, and

means for correcting the drive target values depending on the sensed result from said second sense means so that an inertia force exerted on the object is removed from the force sensed by said first sense means.

14. A robot system comprising:

a robot having at least a joint therein;

joint drive devices for driving said robot;

means disposed at an end of said robot for holding an object;

first sense means for sensing a force (torque) exerted on said hold means;

control means for generating control signals for said joint drive devices depending on the sensed result from said first sense means;

second sense means for sensing an inertia force exerted on said hold means; and

means for correcting the control signals from said control means depending on the sensed result from said second sense means and for supplying resultant signals to said joint drive devices so that an inertia force exerted on the object is removed from the force sensed by said first sense means.

15. A robot system according to claim 14 wherein said second sense means is comprised of an acceleration sensor.

16. A robot system according to claim 14 wherein said second sense means comprises:

a vision device for detecting a movement of said hold means, and

a vision processor for analyzing an output image said vision device.

17. A robot system according to claim 14 wherein said second sense means comprises:

position detectors for detecting positions of said joints of said robot hand, and

an arithmetic unit for effecting an arithmetic processing on detected signals from said position detectors.

18. A robot system according to claim 14 wherein said first sense means and said second sense means are integrally arranged in a unit so as to be connected between said robot and said hold means.

19. A robot system in a microgravity condition comprising:

a robot having at least a joint therein;

joint drive means for driving said joint in said robot;

gripper means disposed at an end of said robot for holding an object;

actuation means for actuating said gripper means;

first sense means for sensing a force (torque) exerted on said gripper means;

second sense means for sensing an inertia force exerted on said gripper means; and

means responsive to the sensed results from said first and second sense means for determining a corrected external force by subtracting a sensed inertia force exerted on the object held by the gripper means from the force sensed by said first sense means and controlling said joint drive means depending on said determined corrected external force.

20. A robot system in a microgravity condition comprising:

a robot having at least a joint therein;

joint drive means for driving said robot;

gripper means disposed at an end of said robot for holding an object;

actuator means for actuating said gripper means;

first sense means for sensing a force (torque) exerted said gripper means;

second sense means for sensing an inertia force exerted on said gripper means;

third sense means for sensing an inertia force exerted on said robot; and

means for controlling the joint drive means depending on sensed results from said first, second and third sense means.

21. A robot system according to claim 20 wherein said first sense means and said second sense means are integrally arranged in a unit so as to be connected between the robot and said gripper means and wherein said third sense means is connected between a base securing said robot and a root portion of said robot.

22. A robot system in a microgravity condition comprising:

a robot having at least a joint therein;

joint drive devices for driving said robot;

gripper means disposed at an end of said robot for holding an object;

first sense means for sensing a force (torque) exerted on said gripper means;

control means for generating control signals for said joint drive devices depending on the sensed result from said first sense means;

second sense means for sensing an inertia force exerted on said gripper means; and

means for correcting the control signals from said control means depending on the sensed result from said second sense means and for supplying resultant signals to said joint drive devices so that an inertia force exerted on the object is removed from the force sensed by said first sense means.