Smart kickstand for balancing a mobile robotic arm

• US 9,889,562 B1
• Filed: 10/16/2015
• Issued: 02/13/2018
• Est. Priority Date: 10/16/2015
• Status: Active Grant

• Current Assignee: X Development LLC (Alphabet Inc.)
• Original Assignee: X Development LLC (Alphabet Inc.)
• Inventors: Rembisz, Justine
• Primary Examiner(s): Holwerda, Stephen
• Application Number:
  US14/885,292
• Time in Patent Office: 851 Days
• CPC Class Codes: B25J 13/088 with position, velocity or acceleration sensors
• CPC Class Codes: B25J 19/0008 Balancing devices
• CPC Class Codes: B25J 5/007 mounted on wheels
• CPC Class Codes: B25J 9/1638 compensation for arm bending/inertia, pay load weight/inertia
• CPC Class Codes: G05B 2219/40298 Manipulator on vehicle, wheels, mobile
• CPC Class Codes: Y10S 901/01 Mobile robot

Abstract

An example system includes a robotic arm coupled to a mobile base. The robotic arm includes a plurality of segments coupled via at least one joint, which includes at least one joint angle sensor. The system also includes a controller configured to carry out operations including receiving, from the at least one joint angle sensor, information indicative of a pose of the robotic arm. The operations include, based on the information indicative of the pose of the robotic arm, determining that a torque induced by the robotic arm is above a predetermined torque threshold. The operations also include causing an adjustable support member to extend out of the mobile base in an orientation that counteracts the torque.

Claims

1. A system comprising:

a mobile base;

a robotic arm coupled to the mobile base, wherein the robotic arm comprises a plurality of arm segments coupled via at least one joint, wherein the at least one joint comprises at least one joint angle sensor;

an adjustable support member coupled to the mobile base, wherein the adjustable support member is configured to be deployed at various angles within a range of rotational angles about a vertical axis, wherein the vertical axis passes through the mobile base; and

a controller comprising a memory and a processor, wherein the memory stores instructions that are executable by the processor to cause the controller to perform operations comprising;

receiving, from the at least one joint angle sensor, information indicative of an angle of the at least one joint;

based on the information indicative of the angle of the at least one joint, determining that a torque induced, at least in part, by the robotic arm is above a predetermined torque threshold, wherein the torque comprises a moment of force about the mobile base, wherein the predetermined torque threshold is based on a balance instability condition of the system; and

causing the adjustable support member to extend out of the mobile base to a deployed position at one of the various angles, within the range of rotational angles, that counteracts the torque.

2. The system of claim 1 wherein the at least one joint angle sensor comprises at least one of:

a magnetic encoder or an optical encoder.

3. The system of claim 1, wherein determining that the torque induced, at least in part, by the robotic arm is above the predetermined torque threshold comprises determining at least one of:

an angle of each arm segment with respect to at least one other arm segment of the plurality of arm segments, a velocity of each arm segment of the plurality of arm segments, or an acceleration of each arm segment of the plurality of arm segments.

4. The system of claim 1, wherein determining that the torque is above the predetermined torque threshold comprises determining a payload of the robotic arm.

5. The system of claim 1, wherein the adjustable support member is configured to extend from the mobile base so as to perform at least one of:

counterbalance the torque;

or

contact a supporting surface.

6. The system of claim 1, wherein the adjustable support member comprises a plurality of telescoping portions and an end portion.

7. The system of claim 6, wherein the end portion comprises at least one of:

an omni-wheel, a foot, a wheel, a vacuum, a mass, or a suction cup.

8. The system of claim 1, wherein the operations further comprise adjusting the adjustable support member based on a change of the torque.

9. The system of claim 1, wherein the adjustable support member is one of a plurality of adjustable support members of the system.

10. The system of claim 9, wherein the plurality of adjustable support members comprise a plurality of rotating portions configured to extend from the mobile base.

11. The system of claim 1, further comprising at least one inertial measurement unit (IMU), wherein the operations further comprise receiving, from the at least one IMU, information indicative of a position and a velocity of the system, and wherein determining that the torque is above the predetermined torque threshold is further based on information received from the at least one IMU.

12. The system of claim 1, further comprising a proximity sensor, wherein the operations further comprise receiving, from the proximity sensor, information indicative of an obstacle in an area around the system, and wherein causing adjustable support member to extend out of the mobile base is based, at least in part, on avoidance of the obstacle detected by the proximity sensor.

13. The system of claim 1, wherein the balance instability condition comprises at least one of:

a tip-over condition, an oscillatory instability condition, or an overspeed condition.

14. The system of claim 1 wherein the operations further comprise planning movements of the robotic arm based on a range of motion of the adjustable support member.

15. A method comprising:

receiving, from at least one joint angle sensor, information indicative of an angle of at least one joint, wherein the at least one joint is coupled to at least one arm segment of a robotic arm, wherein the robotic arm comprises a plurality of arm segments, wherein the robotic arm is coupled to a mobile base;

based on the information indicative of the angle of the at least one joint, determining that a torque induced, at least in part, by the robotic arm is above a predetermined torque threshold, wherein the torque comprises a moment of force about the mobile base, wherein the predetermined torque threshold is based on a balance instability condition of at least the mobile base; and

causing an adjustable support member, which is configured to be deployed at various angles within a range of rotational angles about a vertical axis, to extend out of the mobile base to a deployed position at one of the various angles, within the range of rotational angles, that counteracts the torque.

16. The method of claim 15, wherein determining that the torque induced, at least in part, by the robotic arm is above the predetermined torque threshold comprises determining at least one of:

an angle of each arm segment with respect to at least one other arm segment of the plurality of arm segments, a velocity of each arm segment of plurality of arm segments, or an acceleration of each arm segment of the plurality of arm segments.

17. The method of claim 15, wherein determining that the torque is above the predetermined torque threshold comprises determining a payload of the robotic arm.

18. The method of claim 15, further comprising adjusting the adjustable support member based on a change of the torque.

19. The method of claim 15, further comprising receiving, from an inertial measurement unit (IMU), information indicative of a position and a velocity of the robotic arm or the mobile base, and wherein determining that the torque is above the predetermined torque threshold is further based on information received from the IMU.

20. The method of claim 15, further comprising receiving, from a proximity sensor, information indicative of an obstacle in an area around the mobile base, and wherein causing the adjustable support member to extend out of the mobile base is based, at least in part, on avoidance of the obstacle detected by the proximity sensor.

21. A system comprising:

a mobile base;

a robotic arm coupled to the mobile base, wherein the robotic arm comprises a plurality of arm segments;

at least one inertial measurement unit (IMU) configured to detect a position and a velocity of at least one of the mobile base or the robotic arm;

an adjustable support member coupled to the mobile base, wherein the adjustable support member is configured to be deployed at various angles within a range of rotational angles about a vertical axis, wherein the vertical axis passes through the mobile base; and

a controller comprising a memory and a processor, wherein the memory stores instructions that are executable by the processor to cause the controller to perform operations comprising;

receiving, from the at least one IMU, information indicative of the position and the velocity of at least one of the mobile base or the robotic arm;

based on the information indicative of the position and the velocity of at least one of the mobile base or the robotic arm, determining that a torque induced, at least in part, by the robotic arm is above a predetermined torque threshold, wherein the torque comprises a moment of force about the mobile base, wherein the predetermined torque threshold is based on a balance instability condition of the system; and

causing the adjustable support member to extend out of the mobile base at one of the various angles, within the range of rotational angles, that counteracts the torque.

22. The system of claim 21, wherein the at least one IMU comprises a first IMU coupled to the robotic arm and a second IMU coupled to the mobile base.