Robotic gripper member

Patent metadata

Field	Value
Publication number	US-11097430-B2
Application number	US-201816176138-A
Country	US
Kind code	B2
Filing date	Oct 31, 2018
Priority date	Oct 31, 2017
Publication date	Aug 24, 2021
Grant date	Aug 24, 2021

Abstract

A soft bodied robotic member has the appearance of a finger and has a deformable rubber elongated body surrounding an array of rigid ribs interconnected by a perpendicular constraint. The plates form a series of parallel protrusions extending from opposed sides of the body and have a serrated, sawtooth or wavelike appearance. A tether runs through each row of protrusions and draws the corresponding protrusions together in a compressive manner to bend or dispose the finger toward the compressed side. Gaps between the protrusion allow movement of the protrusion towards adjacent protrusions to dispose the body in an arcuate shape. The constraint is a planar sheet that bends with the arc along its width, but resists lateral twisting, thus limiting movement outside a plane defined by the arc and the tether. Multiple finger members may be placed in close geometric proximity for gripping a common object.

First claim

What is claimed is:

1. A robotic member device, comprising:
an elongated body defining an axis, the body formed from a resilient, deformable medium and having a proximate end and a distal end;
a plurality of protrusions on the body, the protrusions extending from the axis, the protrusions having a tapered cross section extending from a base to a ridge, the base attached to the body and the ridge perpendicular to the axis;
an actuated tether adjacent the elongated body and attached to the distal end at an offset from the axis,
the tether responsive to retraction for disposing the distal end out of axial alignment based on compression along a side of the body; and
a planar constraint embedded in the elongated body, the planar constraint extending parallel to the axis and perpendicular to the protrusions, the constraint adapted to deform from a concave bend away from the axis and toward the retracting tether.

2. The device of claim 1 further comprising an offset, the offset defining attachment of the tether distal from the axis.

3. The device of claim 1 wherein the protrusions extend from the body at spaced increments, the spaced increments defining a gap between adjacent protrusions.

4. The device of claim 3 wherein the body and protrusions are formed from a homogenous molding of the resilient, deformable material.

5. The device of claim 1 wherein the body has a plurality of sides, the protrusions extending from at least one of the sides and having a corresponding tether, the tether secured at the distal end for disposing adjacent protrusions in closer proximity for providing a curved response in the body toward the actuated side.

6. The device of claim 1 wherein the protrusions further comprise rows of protrusions defined by parallel ridges extending perpendicularly from opposed sides of the body.

7. The device of claim 1 wherein the resilient medium is adapted to deform for accommodating movement of adjacent protrusions responsive to tethered retraction.

8. The device of claim 1 wherein the body is adapted for compressive deformation at a base of the protrusions for drawing the ridges of the protrusions closer for disposing the distal end in a direction defined by the retracting actuator.

9. The device of claim 1 further comprising a rigid plate embedded in each of the protrusions.

10. The device of claim 9 further comprising an aperture on the plate, the tether passing through the aperture for maintaining alignment of the compressed protrusions.

11. The device of claim 1 further comprising a planar constraint in the elongated body, the planar constraint extending parallel to the axis and perpendicular to the protrusions, the constraint adapted to deform from a concave bend away from the axis and toward the retracting tether.

12. The device of claim 11 wherein the planar constraint imposes resistant to lateral or twisting movement of the body away from the direction of the compressed side.

13. The device of claim 11 wherein the planar constraint limits deformation to movement in a plane perpendicular to the planar constraint.

14. The device of claim 1 further comprising a plurality of members arranged in a geometric shape, each member defined by an elongated body and operable to converge towards a common point.

15. The device of claim 1 wherein the tethers reduce a distance from the proximate end to the distal end, the elongated body deforming for accommodating the reduced distance.

16. A method of forming a resilient robotic member, comprising:
forming a plurality of similarly sized plates from a rigid material;
forming a mold defining an elongated body and a set of protrusions extending perpendicularly from the body, the protrusions defined by a receptacle sized for receiving the plates;
passing a tether between the plates, the tether secured to at least one of the plates;
disposing the plates in a parallel arrangement in the mold;
encapsulating the plates and the tether by filling the mold with a resilient medium to form a finger member following mold release, the finger member adapted for a curving deformation in response to retraction of the tether for compressing the plates along the retracted tether.

17. The method of claim 16 further comprising interconnecting the parallel plates with a planar constraint, the planar constraint extending parallel to the axis and perpendicular to the protrusions, the constraint adapted to deform from a concave bend toward the retracting tether.

18. The method of claim 17 further comprising inserting the planar constraint through a slot in each of the plates, the planar constraint limiting deformation to movement in a plane perpendicular to the planar constraint.

19. The method of claim 16 further comprising inserting a constraint into the mold, the constraint having a greater rigidity than the resilient medium in at least one dimension.

20. The method of claim 16 further comprising forming a homogeneous molding having a uniform protrusion spacing based on a single pour or injection of the resilient medium.

21. A robotic member, comprising:
an elongated body formed from a resilient, deformable medium defining a robotic control axis;
a plurality of protrusions attached to a side of the body, the protrusions extending substantially perpendicular to the control axis and substantially parallel to each of the other protrusions, the protrusions having a tapered cross section extending from a base to a ridge, the base attached to the body and the ridge perpendicular to the axis;
control tethers extending parallel to the control axis and attached to an actuation source at a proximate end;
a planar constraint embedded in the elongated body, the planar constraint extending parallel to the axis and perpendicular to the protrusions, the constraint adapted to deform from a concave bend away from the axis and toward the retracting tether; and
an aperture in each of the protrusions, the aperture adapted to receive the tether from an adjacent protrusion,

the tether secured to a distal end of the elongated body, the tether adapted to deform the elongated body and draw the protrusions into closer engagement upon retraction of the tether.

Assignees

• Worcester Polytech Inst

Inventors

• Onal Cagdas D
• Ondemir Onder
• Tao Weijia

Classifications

• B25J15/10

  with three or more finger members {(B25J15/0009 takes precedence)} · CPC title

• B25J9/104

  with cables, chains or ribbons · CPC title

• B25J15/12 Primary

  with flexible finger members · CPC title

• B25J9/0015

  Flexure members, i.e. parts of manipulators having a narrowed section allowing articulation by flexion · CPC title

• B25J9/1075

  with muscles or tendons · CPC title