Portable dextrous force feedback master for robot telemanipulation

• US 5,004,391 A
• Filed: 08/21/1989
• Issued: 04/02/1991
• Est. Priority Date: 08/21/1989
• Status: Expired due to Term

• Current Assignee: Rutgers University
• Original Assignee: Rutgers University
• Inventors: Burdea, Grigore C.
• Primary Examiner(s): Bucci, David A.
• Assistant Examiner(s): Underwood, Donald W.
• Application Number:
  US07/396,476
• Time in Patent Office: 589 Days
• Field of Search: 414/4, 414/5, 414/6, 414/7, 294/88, 901/9, 901/34, 336/136
• US Class Current: 414/6
• CPC Class Codes: B25J 13/02 Hand grip control means handles or pedals for crane control B66C13/56; for measuring the force applied to control members G01L5/22; hand-held casings for switching devices, e.g. joy-sticks H01H9/0214
• CPC Class Codes: B25J 13/082 Grasping-force detectors in general G01L5/16, G01L5/22
• CPC Class Codes: B25J 15/0009 comprising multi-articulated fingers, e.g. resembling a human hand
• CPC Class Codes: B25J 3/04 involving servo mechanisms servo-actuated heads B25J15/02

Abstract

An electronic position sensor and a pneumatic microactuator form a portable robot master that may be operated by the fingers of a user'"'"'s hand in the same, natural manner that the user would normally grasp an object to be finger manipulated. The master requires only two contact points to secure its ends to the user'"'"'s fingers and to be manipulated by the user. The master includes a compact, hand-held unit that fits within the space defined by the user'"'"'s palm and fingers, and functions as a position controller for a robot having a dextrous hand. The position sensor includes a linear variable differential transformer having an output signal that is proportional to the distance between the user'"'"'s fingers, i.e. the two contact points, that are used to manipulate the master. A force feedback system, including the pneumatic micro-actuator, senses forces exerted by end effectors on the robot hand and causes a corresponding force to be exerted by the user.

Claims

1. A robot master comprising:

a first support having means for connecting the first support to the thumb of a user'"'"'s hand;

a second support spaced from said first support and having means for connecting the second support to a finger of the user'"'"'s hand; and

displacement means connected to and extending between said supports, wherein said displacement means includes a sensing means, responsive to linear displacements of said supports with respect to each other, for providing an electrical output signal that is a function of the linear distance between said supports, and a slide means extending between said supports for permitting linear displacements of said supports with respect to each other, whereby said displacement means can extend adjacent the palm and between the fingers of the user'"'"'s hand.

2. The robot master of claim 1 wherein the sensing means includes first and second spaced sensing elements having means for sensing the displacement between said spaced sensing elements.

3. The robot master of claim 2 wherein said sensing means is a linear variable differential transformer.

4. The robot master of claim 2 wherein said first sensing element includes an electrical transformer rigidly joined to one of said supports and a magnetic core magnetically coupled to said transformer and joined to the other of said supports.

5. The robot master of claim 2 wherein said supports are rotatably mounted with respect to each other.

6. The robot master of claim 2 wherein said slide means includes a force feedback means mounted between said supports for providing a variable resistance against the displacement of said supports toward each other.

7. The robot master of claim 6 wherein said force feedback means includes a pneumatic cylinder joined to one of the supports, a piston slidably mounted in the cylinder, and a piston rod joined to the piston and to the other of the supports.

8. A robot master comprising:

a first support having means for coupling the first support to the thumb of the user'"'"'s hand;

a second support spaced from said first support and having means for coupling the second support to a finger of the user'"'"'s hand for movement of the supports towards and away from each other along a longitudinal line;

displacement sensing means connected to said supports for providing an output signal that is a function of the distance between said supports, wherein the sensing means includes first and second spaced sensing elements having means for sensing the displacement between said spaced sensing elements and wherein said first sensing element includes an electrical transformer and a magnetic core magnetically coupled to said transformer, said transformer and said core being joined to a different one of said supports; and

a force feedback means mounted between said supports for providing a variable resistance against the displacement of said supports toward each other, wherein said force feedback means includes a pneumatic cylinder joined to one of the supports, a piston slidably mounted in the cylinder, and a piston rod joined to the piston and to the other of the supports.

9. The robot master of claim 8 wherein said transformer is an elongated cylinder having a central longitudinal bore in which said core is suspended.

10. The robot master of claim 9 wherein said transformer and said core have a first, common longitudinal axis, wherein said cylinder and piston have a second, common longitudinal axis, and wherein the first and second axes are parallel to each other and to said longitudinal line.

11. A robot system comprising:

a first support having means for connecting the first support to the thumb of the user'"'"'s hand;

a second support spaced from said first support and having means for connecting the second support to a finger of the user'"'"'s hand;

displacement means connected to and extending between said supports, wherein said displacement means includes a sensing means, responsive to linear displacements of said supports with respect to each other, for providing an electrical output signal that is a function of the linear distance between said supports and a slide means for permitting linear displacements of said supports with respect to each other whereby said displacement means can extend adjacent the palm and between the fingers of the user'"'"'s hand;

a robot hand having end effectors; and

control means connected to the output signal of said sensing means by a flexible line for transmitting said output signal to said control means, and said control means connected to said robot hand for moving the end effectors a predetermined distance with respect to each other in response to the value of the output signal.

12. The robot system of claim 11 wherein the sensing means includes first and second spaced sensing elements having means for sensing the displacement between said spaced sensing elements.

13. The robot system of claim 12 wherein said slide means includes a force feedback means mounted between said supports for providing a variable resistance against the displacement of said supports toward each other.

14. The robot system of claim 13 further including a force sensing means mounted on the robot hand for sensing a manipulation force of one of the end effectors and for providing a feedback signal to said control means proportional to said manipulation force, and wherein said control means includes means for varying the resistance of said force feedback means in response to changes in the feedback signal.

15. The robot system of claim 14 wherein the robot hand includes a plurality of tendons connected to said end effectors and wherein said force sensing means includes a strain gauge mounted on one of said tendons for sensing the force therein.

16. A robot system comprising:

a first support having means for coupling the first support to the thumb of the user'"'"'s hand;

a second support spaced from said first support and having means for coupling the second support to a finger of the user'"'"'s hand of movement of the supports toward and away from each other along a longitudinal line;

a force feedback means mounted between said supports for providing a variable resistance against the displacement of said supports toward each other, said force feedback means including a pneumatic cylinder joined to one of the supports and a piston slidably mounted in the cylinder and having a piston rod joined to the other of the supports;

displacement sensing means connected to said supports for providing an output signal that is a function of the distance between said supports;

a robot hand having end effectors;

control means connected to output signal of said sensing means and said robot hand for moving the end effectors a predetermined distance with respect to each other in response to the value of the output signal; and

a force sensing means mounted on the robot hand for sensing a manipulation force of one of the end effectors and for providing a feedback signal to said control means proportion to said manipulation force, wherein said control means includes means for varying the resistance of said force feedback means in response to changes in the feedback signal, said robot hand includes a plurality of tendons connected to said end effectors, said force sensing means includes a strain gauge mounted on one of said tendons for sensing the force therein, said sensing means includes first and second spaced sensing elements having means for sensing the displacement between said spaced sensing elements.

17. The robot system of claim 16 wherein said control means includes means for varying the air pressure in said piston as a function of said feedback signal.

18. The robot system of claim 17 wherein said first sensing element includes an electrical transformer and a magnetic core magnetically coupled to said transformer, said transformer and said core being joined to a different one of said supports.

19. The robot system of claim 18 wherein said transformer is an elongated cylinder having a central longitudinal bore in which said core is suspended.

20. The robot system of claim 19 wherein said transformer and said core have a first, common longitudinal axis, wherein said cylinder and pistol have a second, common longitudinal axis, and wherein the first and second axes are parallel to each other and to said longitudinal line.