Sprung worm gripper for a robotic device

Patent metadata

Field	Value
Publication number	US-10933536-B2
Application number	US-201816005736-A
Country	US
Kind code	B2
Filing date	Jun 12, 2018
Priority date	May 4, 2016
Publication date	Mar 2, 2021
Grant date	Mar 2, 2021

Abstract

A robotic gripping device is provided. The device includes a finger having a worm gear coupled to its base end. The device also includes an actuator having a motor and a shaft, wherein the shaft is configured to rotate a worm coupled to the worm gear, and the actuator is mounted on a carriage such that the actuator is configured to slide along an axis. The device also includes a spring having first and second ends, wherein the first end is coupled to the motor and the second end is fixed. Further, the actuator is configured to (i) rotate the shaft relative to the motor by a first amount to move the finger toward an object, and (ii) when the finger is in contact with the object and is prevented from further movement, further rotate the shaft relative to the motor to slide the actuator along the axis.

First claim

What is claimed is:

1. A robotic gripping device comprising:
a finger having a worm gear coupled to a base end of the finger;
an actuator having a motor and a shaft, wherein the shaft is configured to rotate a worm coupled to the worm gear, and wherein the actuator is mounted on a carriage such that the actuator is configured to slide along an axis; and
a spring surrounding at least the motor of the actuator and having a first end and a second end, wherein the first end is coupled to the motor of the actuator and the second end is fixed, such that the actuator is held in a first position along the axis when the spring is at equilibrium;
wherein the actuator is configured to:
rotate the shaft relative to the motor by a first amount, thereby rotating the worm and the worm gear to move the finger toward an object; and
when the finger is in contact with the object and the finger is prevented from further movement, further rotate the shaft relative to the motor to slide the actuator along the axis to a second position at which the spring is no longer at equilibrium.

2. The robotic gripping device of claim 1 , further comprising:
a linear encoder configured to determine a difference between the first position and the second position; and
a control system, wherein the control system is configured to determine an amount of torque applied to the finger based on the difference between the first position and the second position.

3. The robotic gripping device of claim 1 , wherein the spring surrounding at least the motor of the actuator comprises at least the motor of the actuator being disposed within a coil of the spring.

4. The robotic gripping device of claim 1 , wherein the finger comprises a first finger, and wherein the robotic gripping device further comprises a second finger having a respective worm gear and associated worm, actuator, and spring.

5. The robotic gripping device of claim 1 , wherein a shape of the worm gear is a partial circle, and wherein the actuator is configured to disengage the worm from the worm gear when a torque greater than a threshold torque is applied to the finger.

6. The robotic gripping device of claim 1 , wherein the finger is an underactuated finger.

7. The robotic gripping device of claim 1 , wherein the finger is configured to move translationally.

8. The robotic gripping device of claim 1 , wherein the finger is configured to move rotationally about an axis defined by the worm gear.

9. A robotic device comprising:
a robotic gripping device, wherein the robotic gripping device comprises:
a finger having a worm gear coupled to a base end of the finger;
an actuator having a motor and a shaft, wherein the shaft is configured to rotate a worm coupled to the worm gear, and wherein the actuator is mounted on a carriage such that the actuator is configured to slide along an axis; and
a spring surrounding at least the motor of the actuator and having a first end and a second end, wherein the first end is coupled to the motor of the actuator and the second end is fixed, such that the actuator is held in a first position along the axis when the spring is at equilibrium; and

a control system configured to control the robotic gripping device, wherein the control system comprises:
one or more processors;
a non-transitory computer-readable memory; and
program instructions stored on the non-transitory computer-readable memory and executable by the one or more processors to:
cause the actuator to rotate the shaft relative to the motor by a first amount, thereby rotating the worm and the worm gear to move the finger toward an object; and
when the finger is in contact with the object and the finger is prevented from further movement, cause the actuator to further rotate the shaft relative to the motor to slide the actuator along the axis to a second position at which the spring is no longer at equilibrium.

10. The robotic device of claim 9 , further comprising:
a linear encoder configured to determine a difference between the first position and the second position, wherein the program instructions are further executable to determine an amount of torque applied to the finger based on the difference between the first position and the second position.

11. The robotic device of claim 9 , wherein the spring surrounding at least the motor of the actuator comprises at least the motor of the actuator being disposed within a coil of the spring.

12. The robotic device of claim 9 , wherein the finger comprises a first finger, and wherein the robotic gripping device further comprises a second finger having a respective worm gear and associated worm, actuator, and spring.

13. The robotic device of claim 9 , wherein a shape of the worm gear is a partial circle, and wherein the actuator is configured to disengage the worm from the worm gear when a torque greater than a threshold torque is applied to the finger.

14. The robotic device of claim 9 , wherein the finger is configured to move translationally.

15. The robotic device of claim 9 , wherein the finger is configured to move rotationally about an axis defined by the worm gear.

16. A method comprising:
identifying an object for a robotic gripping device to grasp, wherein the robotic gripping device comprises a finger, an actuator, and a spring, wherein:
the finger has a worm gear coupled to a base end of the finger,
the actuator has a motor and a shaft, wherein the shaft rotates a worm coupled to the worm gear, and wherein the actuator is mounted on a carriage such that the actuator is configured to slide along an axis; and
the spring surrounds at least the motor of the actuator and has a first end and a second end, where the first end is coupled to the motor of the actuator and the second end is fixed, such that the actuator is held in a first position along the axis when the spring is at equilibrium;

rotating the shaft relative to the motor by a first amount, thereby rotating the worm and the worm gear to move the finger toward an object; and
when the finger is in contact with the object and the finger is prevented from further movement, further rotating the shaft relative to the motor to slide the actuator along the axis to a second position at which the spring is no longer at equilibrium.

17. The method of claim 16 , wherein the robotic gripping device further comprises a linear encoder configured to determine a difference between the first position and the second position, wherein the method further comprises:
determining an amount of torque applied to the finger based on the difference between the first position and the second position.

18. The method of claim 16 , wherein the spring surrounding at least the motor of the actuator comprises at least the motor of the actuator being disposed within a coil of the spring.

19. The method of claim 16 , wherein the finger comprises a first finger having a respective first shaft, motor, actuator, spring, worm gear, and worm, and the robotic gripping device further comprises a second finger having a respective second shaft, motor, actuator, spring, worm gear, and worm, wherein the method further comprises:
for each of the first and second respective shafts, motors, actuators, springs, worm gears, and worms:
rotating the shafts relative to the motors by first amounts, thereby rotating the worms and the worm gears to move the fingers toward an object; and
when the fingers are in contact with the object and the fingers are prevented from further movement, further rotating the shafts relative to the motors

Assignees

• X Dev Llc

Inventors

• Strauss Marc

Classifications

• B25J15/0213 Primary

  actuated by gears · CPC title

• B25J15/0028

  with movable, e.g. pivoting gripping jaw surfaces · CPC title

• B25J15/0009 Primary

  comprising multi-articulated fingers, e.g. resembling a human hand · CPC title

• B25J9/126

  Rotary actuators · CPC title

• B25J9/102

  Gears specially adapted therefor, e.g. reduction gears (gearings in general F16H) · CPC title