Kinematic design for robotic arm

• US 9,827,678 B1
• Filed: 05/16/2016
• Issued: 11/28/2017
• Est. Priority Date: 05/16/2016
• Status: Active Grant

• Current Assignee: X Development LLC (Alphabet Inc.)
• Original Assignee: X Development LLC (Alphabet Inc.)
• Inventors: Gilbertson, Seth, Weber, Jeff, Wilson, Robert
• Primary Examiner(s): Tran, Khoi
• Assistant Examiner(s): Peche, Jorge
• Application Number:
  US15/155,388
• Time in Patent Office: 561 Days
• Field of Search: 700245, 74490, 7449001
• CPC Class Codes: A47L 11/24 Floor-sweeping machines, motor-driven
• CPC Class Codes: A47L 11/4011 Regulation of the cleaning machine by electric means; Control systems and remote control systems therefor
• CPC Class Codes: A47L 11/4055 for lifting the tools to a non-working position
• CPC Class Codes: A47L 11/4061 Steering means; Means for avoiding obstacles; Details related to the place where the driver is accommodated
• CPC Class Codes: A47L 2201/00 Robotic cleaning machines, i.e. with automatic control of the travelling movement or the cleaning operation
• CPC Class Codes: B25J 11/0085 Cleaning
• CPC Class Codes: B25J 15/0014 having fork, comb or plate shaped means for engaging the lower surface on a object to be transported
• CPC Class Codes: B25J 15/0066 with different types of end effectors, e.g. gripper and welding gun B25J15/0057 and B25J15/0061 take precedence
• CPC Class Codes: B25J 18/025 telescopic
• CPC Class Codes: B25J 19/007 Means or methods for designing or fabricating manipulators
• CPC Class Codes: B25J 9/0087 Dual arms double SCARA arms B25J9/043
• CPC Class Codes: B25J 9/046 Revolute coordinate type
• CPC Class Codes: B25J 9/1682 Dual arm manipulator; Coordination of several manipulators
• CPC Class Codes: B25J 9/1694 characterised by use of sensors other than normal servo-feedback from position, speed or acceleration sensors, perception control, multi-sensor controlled systems, sensor fusion
• CPC Class Codes: Y10S 901/01 Mobile robot
• CPC Class Codes: Y10S 901/41 Tool

Abstract

An example robotic arm includes a base linkage and a first end effector connected to a second end of the base linkage through a first rotational joint. The robotic arm additionally includes a control arm. The control arm includes a first linkage and a second linkage, each having a first end and a second end. The first end of the first linkage is connected to the second end of the base linkage through a second rotational joint. The first end of the second linkage is connected to the second end of the first linkage through a third rotational joint. The control arm also includes a second end effector connected to the second end of the second linkage through a fourth rotational joint. The first, second, third, and fourth rotational joints are configured to rotate in or parallel to a first plane.

Claims

1. A robotic arm comprising:

a base linkage having a first end and a second end;

a first end effector connected to the second end of the base linkage through a first rotational joint configured to allow the first end effector to rotate in a first plane; and

a control arm comprising;

a first linkage having a first end and a second end, the first end of the first linkage connected to the second end of the base linkage through a second rotational joint configured to allow the first linkage to rotate in or parallel to the first plane;

a second linkage having a first end and a second end, the first end of the second linkage connected to the second end of the first linkage through a third rotational joint configured to allow the second linkage to rotate in or parallel to the first plane; and

a second end effector connected to the second end of the second linkage through a fourth rotational joint configured to allow the second end effector to rotate in or parallel to the first plane.

2. The robotic arm of claim 1, wherein at least one of the first actuated rotational joint, the second actuated rotational joint, the third actuated rotational joint, and the fourth actuated rotational joint is actuated by a harmonic drive mounted within the joint.

3. The robotic arm of claim 1, further comprising a control system configured to:

provide instructions to actuate the first rotational joint to rotate the first end effector to a first orientation;

provide instructions to actuate the second rotational joint to rotate the control arm to a second orientation;

provide instructions to actuate the third rotational joint to align the second end effector with the first end effector based on the first orientation and the second orientation; and

provide instructions to actuate the fourth rotational joint to operate the second end effector in coordination with the first end effector.

4. The robotic arm of claim 1, wherein:

the control arm is offset from the base linkage in a direction perpendicular to the first plane by a first distance to allow the robotic arm to fold into a compact form, wherein folding into a compact form comprises;

positioning the first linkage parallel to the base linkage such that the second end of the second linkage is positioned adjacent to the first end of the base linkage; and

positioning the second linkage parallel to the base linkage and the first linkage such that the second end of the second linkage is positioned adjacent to the first end of the first linkage and the second end of the base linkage; and

the robotic arm is controlled by a control system configured to provide instructions to cause the robotic arm to fold into the compact form.

5. The robotic arm of claim 1, wherein the first end of the base linkage is connected to a support base through a fifth actuated joint configured to move the base linkage with at least one degree of freedom.

6. The robotic arm of claim 5, wherein the robotic arm is controlled by a control system configured to:

provide instructions to cause the control arm to move the second end effector to grasp an object between the second end effector and the first end effector by pressing the object against the first end effector using the second end effector;

provide instructions to cause the base linkage to move the object grasped between the second end effector and the first end effector to a drop-off location by causing the fifth actuated joint to move the base linkage with the at least one degree of freedom; and

provide instructions to cause the control arm to move the second end effector to release, at the drop-off location, the object grasped between the second end effector and the first end effector.

7. The robotic arm of claim 5, wherein the robotic arm is controlled by a control system configured to:

provide instructions to actuate the first rotational joint to rotate the first end effector to a first orientation;

provide instructions to actuate the second rotational joint to rotate the control arm to a second orientation;

provide instructions to actuate the third rotational joint to align the second end effector with the first end effector based on the first orientation and the second orientation; and

provide instructions to actuate the fourth rotational joint to operate the second end effector in coordination with the first end effector;

provide instructions to actuate the fifth actuated joint to move the base linkage with the at least one degree of freedom;

provide instructions to maintain a constant pitch of the first end effector by adjusting the orientation of the first end effector as the base linkage is moved with the at least one degree of freedom; and

provide instructions to maintain the second end effector in a constant position in relation to the first end effector by adjusting the orientation of the control arm in response to adjustments in the orientation of the first end effector.

8. The robotic arm of claim 5, wherein the robotic arm is controlled by a control system configured to:

provide instructions to cause the control arm to move the second end effector to push an object onto the first end effector;

provide instructions to cause the base linkage to move the object disposed on the first end effector to a drop-off location by causing the fifth actuated joint to move the base linkage with the at least one degree of freedom; and

provide instructions to cause the first end effector to drop off, at the drop-off location, the object disposed on the first end effector.

9. The robotic arm of claim 1, wherein the base linkage comprises an actuated telescopic linkage configured to extend a length of the base linkage.

10. The robotic arm of claim 9, wherein the first end of the base linkage is connected to a base through a fifth actuated joint configured to move the base linkage with at least one degree of freedom;

and wherein the robotic arm is controlled by a control system configured to;

provide instructions to cause the control arm to move the second end effector to grasp an object between the second end effector and the first end effector by pressing the object against the first end effector using the second end effector;

provide instructions to cause the base linkage to move the object to a drop-off location while the object is grasped between the second end effector and the first end effector by;

causing the fifth actuated joint to move the base linkage with the at least one degree of freedom; and

causing the actuated telescopic linkage to extend the length of the base linkage in order to reach the drop-off location; and

provide instructions to cause the control arm to move the second end effector to release, at the drop-off location, the object grasped between the second end effector and the first end effector.

11. The robotic arm of claim 1, wherein:

the first end effector is a shovel tool;

the second end effector is a sweeping tool; and

the robotic arm is controlled by a control system configured to provide instructions to cause the sweeping tool to move an object onto the shovel tool.

12. The robotic arm of claim 1, wherein:

the first end effector is a storage container;

the second end effector is a gripper; and

the robotic arm is controlled by a control system configured to provide instructions to cause the gripper to pick up an object and place the object in the storage container.

13. The robotic arm of claim 1, wherein the robotic arm is controlled by a control system configured to determine a range of motion limit of at least one of the first rotational joint, the second rotational joint, the third rotational joint, and the fourth rotational joint based on a position of at least one of the base linkage, the first linkage, the second linkage, the first end effector, and the second end effector.

14. The robotic arm of claim 13, wherein the robotic arm is controlled by a control system configured to determine a range of motion limit of the fourth rotational joint based on a position of the second end of the second linkage with respect to the first end effector.

15. A method comprising:

actuating a first rotational joint to rotate a first end effector of a robotic device to a first orientation, wherein the first end effector is connected to a second end of a base linkage through the first rotational joint, and wherein the first rotational joint is configured to rotate the first end effector in a first plane;

actuating a second rotational joint to rotate a control arm of a robotic device to a second orientation, wherein a first end of a first linkage of the control arm is connected to the second end of the base linkage through the second rotational joint, and wherein the second rotational joint is configured to rotate the control arm in or parallel to the first plane;

actuating a third rotational joint to align a second end effector with the first end effector based on the first orientation and the second orientation, wherein the second end effector is connected to a second end of a second linkage of the control arm, wherein a first end of the second linkage is connected to a second end of the first linkage through the third actuated rotational joint, and wherein the third actuated rotational joint is configured to rotate the second linkage in or parallel to the first plane; and

actuating a fourth rotational joint to operate the second end effector in coordination with the first end effector, wherein the second end effector is connected to the second end of the second linkage through the fourth rotational joint, and wherein the fourth rotational joint is configured to rotate the second end effector in or parallel to the first plane.

16. The method of claim 15, wherein a first end of the base linkage is connected to a support base through a fifth actuated joint configured to move the base linkage with at least one degree of freedom, the method further comprising:

causing the fifth actuated joint to move the base linkage with the at least one degree of freedom;

maintaining a constant pitch of the first end effector by adjusting the orientation of the first end effector as the base linkage is moved with the at least one degree of freedom; and

maintaining the second end effector in a constant position in relation to the first end effector by adjusting the orientation of the control arm in response to adjustments in the orientation of the first end effector.

17. The method of claim 15, wherein the control arm is offset from the base linkage in a direction perpendicular to the first plane by a first distance to allow the robotic arm to fold into a compact form, the method further comprising causing the robotic arm to fold into a compact form, wherein folding into a compact form comprises:

positioning the first linkage parallel to the base linkage such that the second end of the second linkage is positioned adjacent to the first end of the base linkage; and

positioning the second linkage parallel to the base linkage and the first linkage such that the second end of the second linkage is positioned adjacent to the first end of the first linkage and the second end of the base linkage.

18. The method of claim 15, wherein actuating the fourth rotational joint to operate the second end effector in coordination with the first end effector comprises rotating the second end effector to grasp an object between the second end effector and the first end effector by pressing the object against the first end effector using the second end effector, the method further comprising:

actuating a fifth actuated joint to move the base linkage in order to move the object grasped between the second end effector and the first end effector to a drop-off location, wherein the fifth actuated joint connects the first end of the base linkage to a support base; and

causing the control arm to move the second end effector to release, at the drop-off location, the object grasped between the second end effector and the first end effector.

19. The method of claim 15, wherein the base linkage comprises an actuated telescopic linkage configured to extend a length of the base linkage.

20. A robotic device comprising:

a mobile base;

a base linkage having a first end and a second end, the first end of the base linkage connected to the mobile base;

a first end effector connected to the second end of the base linkage through a first rotational joint configured to allow the first end effector to rotate in a first plane; and

a control arm comprising;

a first linkage having a first end and a second end, the first end of the first linkage connected to the second end of the base linkage through a second rotational joint configured to allow the first linkage to rotate in or parallel to the first plane;

a second linkage having a first end and a second end, the first end of the second linkage connected to the second end of the first linkage through a third rotational joint configured to allow the second linkage to rotate in or parallel to the first plane; and

a second end effector connected to the second end of the second linkage through a fourth rotational joint configured to allow the second end effector to rotate in or parallel to the first plane.