Control system for a grasping device

• US 9,174,339 B2
• Filed: 11/21/2011
• Issued: 11/03/2015
• Est. Priority Date: 11/22/2010
• Status: Active Grant

• Current Assignee: Vanderbilt University
• Original Assignee: Vanderbilt University
• Inventors: Goldfarb, Michael, Dalley, Skyler, Varol, Huseyin Atakan
• Primary Examiner(s): Tran, Khoi
• Assistant Examiner(s): NGUYEN, ROBERT T
• Application Number:
  US13/988,820
• Publication Number:
  US 20130253705A1
• Time in Patent Office: 1,443 Days
• US Class Current: 1/1
• CPC Class Codes: A61B 5/11 Measuring movement of the entire body or parts thereof, e.g. head or hand tremor, mobility of a limb for measuring pulse A61B5/02 ;A61B5/1038 takes precedence; motion detection to correct for motion artifacts in physiological signals A61B5/721
• CPC Class Codes: A61F 2/583 Hands; Wrist joints
• CPC Class Codes: A61F 2/586 Fingers
• CPC Class Codes: A61F 2/68 Operating or control means
• CPC Class Codes: A61F 2/70 electrical
• CPC Class Codes: A61F 2/72 Bioelectric control, e.g. myoelectric
• CPC Class Codes: A61F 2002/587 Thumbs
• CPC Class Codes: A61F 2002/6872 attached and mechanically operated by remaining muscle bioelectrical control A61F2/72
• CPC Class Codes: A61F 2002/704 computer-controlled, e.g. robotic control
• CPC Class Codes: A61F 2002/7625 for measuring angular position
• CPC Class Codes: A61F 2002/7635 for measuring force, pressure or mechanical tension
• CPC Class Codes: A61F 2002/764 for measuring acceleration
• CPC Class Codes: B25J 15/0009 comprising multi-articulated fingers, e.g. resembling a human hand
• CPC Class Codes: B25J 15/08 having finger members B25J15/02, B25J15/04 take precedence
• CPC Class Codes: B25J 15/10 with three or more finger members B25J15/0009 takes precedence
• CPC Class Codes: B25J 9/0006 Exoskeletons, i.e. resembling a human figure
• CPC Class Codes: B25J 9/02 characterised by movement of the arms, e.g. cartesian coordinate type B25J9/06 takes precedence
• CPC Class Codes: B25J 9/10 characterised by positioning means for manipulator elements
• CPC Class Codes: B25J 9/1612 characterised by the hand, wrist, grip control
• CPC Class Codes: Y10S 901/15 Jointed arm

Abstract

A method for operating a grasping device and grasping devices therefrom are provided. The grasping device is configured to use a plurality of parallel, bi-directional state flow maps each defining a sequence of poses for a plurality of joints in the grasping device. The method include receiving at least one control signal, determining a current pose of the grasping device within the one of the plurality of state flow maps currently selected for the grasping device, and selectively actuating the plurality of joints to traverse the sequence of poses, where a direction for traversing the sequence of poses is based on the at least one control signal.

Claims

1. A method for operating a grasping device using a plurality of parallel, bi-directional state flow maps each defining a sequence of poses for a plurality of joints in the grasping device, the method comprising:

receiving at least one control signal;

determining a current pose of the grasping device within the one of the plurality of state flow maps currently selected for the grasping device; and

selectively actuating the plurality of joints to traverse the sequence of poses, wherein a direction for traversing the sequence of poses is based on the at least one control signal,

wherein a first of the plurality of state flows comprises a sequence comprising a platform pose with the thumb in repose, a pointing pose, a hook pose, and a lateral pinch pose.

2. The method of claim 1, wherein selectively actuating the plurality of joints further comprises automatically transitioning to a next one of the sequence of poses in the direction if the at least one control signal meets a threshold criteria based on at least one of an intensity and a length of the at least one signal.

3. The method of claim 1, wherein the actuating of the plurality of joints further comprises:

detecting a hindrance to motion for the plurality of joints; and

adjusting an amount of actuating allowed for the plurality of joints between the sequence of poses based on a magnitude of the hindrance.

4. The method of claim 1, wherein the actuating of the plurality of joints further comprises:

measuring a grasping force; and

adjusting an amount of actuating allowed for the plurality of joints between the sequence of poses based on a magnitude of the grasping force.

5. The method of claim 1, wherein the actuating of the plurality of joints further comprises:

measuring at least one of an acceleration or an angular velocity of the grasping device and

adjusting an amount of actuating allowed for the plurality of joints between the sequence of poses based on a magnitude of the acceleration or the angular velocity.

6. The method of claim 1, wherein the at least one control signal is based on an at least one electromyogram (EMG) signal.

7. The method of claim 6, wherein the at least one EMG signal is received from first and second channels of EMG signals, wherein the first channel of EMG signals is used to provide control signals for traversing the plurality of poses in a first direction and the second channel of EMG signals is used to provide control signals for traversing the plurality of poses in a second direction opposite to the first direction.

8. The method of claim 6, wherein if a magnitude of the at least one EMG signal falls below a transition threshold for the current pose, an alternate version of the current pose is selected.

9. The method of claim 1, wherein prior to the selective actuating of the plurality of joints, the method further comprises:

ascertaining whether the at least one control signal is a transition signal; and

when the at least one control signal is a transition signal and the current pose is a transition pose within the one of the plurality of state flow maps, selecting a different one of the plurality of state flow maps for the grasping device.

10. The method of claim 9, wherein the switching between state-flow maps results in an automated repositioning of the hand from the transition pose in one of the plurality of state flow maps to a corresponding transition pose in the different one of the plurality of state flow maps.

11. The method of claim 1, wherein a second of the plurality of state flows comprises a sequence comprising a platform pose with the thumb in opposition, a tip pose, and a chuck pose.

12. The method of claim 11, wherein the grasping device can only switch between the first of the plurality of state flow maps and the second of the plurality of state flow maps only from corresponding platform poses.

13. A grasping device, comprising:

a plurality of joints;

a memory for storing a plurality of parallel, bi-directional state flow maps that each defining a sequence of poses for the plurality of joints; and

a processor communicatively coupled to the memory and the plurality of joints, wherein the processor is configured for;

receiving at least one control signal;

determining a current pose of the grasping device within the one of the plurality of state flow maps currently selected for the grasping device; and

selectively actuating the plurality of joints to traverse the sequence of poses, wherein a direction for traversing the sequence of poses is based on the at least one control signal,

wherein a first of the plurality of state flows comprises a sequence comprising a platform pose with the thumb in repose, a pointing pose, a hook pose, and a lateral pinch pose, a second of the plurality of state flows comprises a sequence comprising a platform pose with the thumb in opposition, a tip pose, and a chuck pose, and wherein the grasping device can only switch between the first of the plurality of state-flow maps and the second of the plurality of state-flow maps only from corresponding platform poses.

14. The device of claim 13, wherein the processor is further configured for selectively actuating the plurality of joints further comprises automatically transitioning to a next one of the sequence of poses in the direction if the at least one control signal meets a threshold criteria based on at least one of an intensity and a length of the at least one signal.

15. The device of claim 13, wherein the actuating of the plurality of joints further comprises:

detecting at least one of a hindrance to motion, a grasping force, an acceleration, or an angular velocity for the plurality of joints to yield a detected force; and

adjusting an amount of actuating allowed for the plurality of joints between the sequence of poses based on a magnitude and a type of the detected force.

16. The device of claim 13, wherein the at least one control signal is based on an at least one electromyogram (EMG) signal.

17. The device of claim 13, wherein prior to the selective actuating of the plurality of joints, the method further comprises:

ascertaining whether the at least one control signal is a transition signal; and

when the at least one control signal is a transition signal and the current pose is a transition pose within the one of the plurality of state flow maps, selecting a different one of the plurality of state flow maps for the grasping device and automatically repositioning of the hand from the transition pose in one of the plurality of state flow maps to a corresponding transition pose in the different one of the plurality of state flow maps.

18. A grasping device, comprising:

a plurality of joints;

a memory for storing a plurality of parallel, bi-directional state flow maps that each defining a sequence of poses for the plurality of joints; and

a processor communicatively coupled to the memory and the plurality of joints, wherein the processor is configured for;

receiving at least one control signal;

determining a current pose of the grasping device within the one of the plurality of state flow maps currently selected for the grasping device; and

selectively actuating the plurality of joints to traverse the sequence of poses, wherein a direction for traversing the sequence of poses is based on the at least one control signal,

wherein the at least one control signal is based on an at least one electromyogram (EMG) signal, wherein the at least one EMG signal is received from first and second channels of EMG signals, wherein the first channel of EMG signals is used to provide control signals for traversing the plurality of poses in a first direction and the second channel of EMG signals is used to provide control signals for traversing the plurality of poses in a second direction opposite to the first direction, and wherein a co-contraction in at least one of the first and second channels of EMG is used to provide control signals for transitioning between different ones of the plurality of state flow maps.