Compliant underactuated robotic hand

Abstract

A robotic hand comprising: a set of at least two fingers having at least one compliant articulated finger comprising links, joints, and at least one tendon; and an actuating palm connected to the set of finger and operable to tense and relax the at least one tendon to cause least two of the fingers to respectively grip and release an object.

Description

COMPLIANT UNDERACTUATED ROBOTIC HANDRELATED APPLICATIONS

[0001] The present application claims the benefit under 35 U.S.C. 119(e) of U.S. Provisional Application 63 / 606,611, filed on December 06, 2023, the disclosure of which is incorporated herein by reference in its entirety.FIELD

[0002] Embodiments of the disclosure relate to robotic hands.BACKGROUND

[0003] Robots and robotic assistants configured to replace and / or assist humans are proliferating and engage in an ever-expanding variety of applications from relatively simple pick and place tasks, serving coffee in paper cups, to carrying out surgeries on the human body, and operating in environments that are hazardous to human beings. Operating effectively and economically in sterile or hazardous environments typically presents a complex and demanding set of constraints on design and materials of robotic hands that are intended to operate in the environments.SUMMARY

[0004] An aspect of an embodiment of the disclosure relates to providing a robotic hand comprising a compliant, underactuated set of articulated fingers comprising links, joints, and tendons that may be relatively easily produced and conveniently attached to and detached from a robotic actuating palm that controls the fingers by tensing and relaxing the tendons. In an embodiment the complete set of fingers, including links, joints, and tendons, may be integrally manufactured in a “one-shot” 3D printing session, ready to be attached to and operated by an actuating palm that operates the tendons. The fingers may be referred to as Print-N-Grip (PNG) fingers and the robot hand may be referred to as a Print-N-Grip, PNG hand.

[0005] In an embodiment, a PNG hand may comprise two or more PNG fingers. Optionally all of the PNG fingers are produced having each tendon of a given PNG finger joined with a respectively homologous tendon of at least one other PNG finger at a common tendon join of the given PNG finger and the at least one other PNG finger. Optionally, the at least one other PNG finger comprises all of the other PNG fingers in the PNG hand. At least one activator comprised in the PNG palm is connected to the common tendon join / s to control grasping motion of the fingers. In an embodimentthe at least one activator comprises a reel motor coupled to the tendon join by a pull band. The reel motor reels in the pull band to bend and move the fingers toward each other and close the hand to grip an object. The reel motor reels out the pull band to straighten and move the fingers away from each other to open the hand and release the object.

[0006] In an embodiment a PNG hand may comprise a set of fingers comprising at least one PNG finger and a non-prehensile finger, optionally characterized by a relatively fixed shape, that functions as an opposable thumb to a PNG finger of the at least one PNG finger.

[0007] In an embodiment a PNG hand may comprise at least one PNG finger configured to be operable on its own by tensing a tendon to grasp an object by curling around at least a portion of the object and to release the object by relaxing the tendon to allow the finger to uncurl.

[0008] In an embodiment a PNG finger may comprise a single tendon or two or more tendons.

[0009] This Summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This Summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter.BRIEF DESCRIPTION OF FIGURES

[0010] Non-limiting examples of embodiments of the disclosure are described below with reference to figures attached hereto that are listed following this paragraph. Identical features that appear in more than one figure may be labeled with a same label in multiple figures in which they appear. A label labeling an icon representing a given feature of an embodiment of the disclosure in a figure may be used to reference the given feature. Dimensions of features shown in the figures are chosen for convenience and clarity of presentation and are not necessarily shown to scale.

[0011] Fig. 1A shows a set of photographs illustrating a robot hand picking up a set of keys, in accordance with an embodiment of the disclosure;

[0012] Fig. IB shows a set of photographs illustrating a robot hand picking up a coin, in accordance with an embodiment of the disclosure;

[0013] Fig. 1C shows a photograph illustrating a robot hand gripping and removing a wet wipe tissue from a container, in accordance with an embodiment of the disclosure;

[0014] Fig. 2A schematically shows a robot hand similar to that shown in Figs. 1 A-1C comprising a set of two opposable articulated fingers and an actuator palm, in accordance with an embodiment of the disclosure;

[0015] Fig. 2B schematically show an enlarged perspective view of the set of PNG fingers comprised in the PNG hand shown in Fig. 2A, in accordance with an embodiment of the disclosure;

[0016] Fig. 2C schematically shows a partially exploded and partially transparent view of the PNG hand shown in Fig. 2B in which a portion of a housing of the robot hand is transparent to display details of the internal construction the robot hand, in accordance with an embodiment of the disclosure;

[0017] Fig. 2D schematically shows the partially exploded view of the PNG hand shown in Fig. 2C in which the transparent portion of the housing of the robot hand shown in Fig. 2C is absent, in accordance with an embodiment of the disclosure;

[0018] Figs. 3 A-3E schematically show details of features of an actuator comprised in the PNG robot hand shown in Figs. 2A-2D and details of assembly of the actuator to the PNG fingers of the robot hand, in accordance with an embodiment of the disclosure;

[0019] Fig. 4A schematically shows a robot hand comprising a set of articulated opposable fingers that is smaller than those shown in Figs. 1 A-3D after scaling the set of fingers, in accordance with an embodiment of the disclosure;

[0020] Figs. 4B and 4C schematically show partially exploded views of the robot hand shown in Fig. 4A, in accordance with an embodiment of the disclosure;

[0021] Fig. 5 shows a photograph of a set of two 3D-printed articulated opposable fingers as they appear upon removal from a 3D-printer that printed them, in accordance with an embodiment of the disclosure; and

[0022] Fig. 6 shows a photograph of a set of four 3D-printed articulated fingers as they appear upon removal from a 3D-printer that printed them, in accordance with an embodiment of the disclosure.DETAILED DESCRIPTION

[0023] In the discussion, unless otherwise stated, adjectives such as “substantially” and “about” modifying a condition or relationship characteristic of a feature or features of an embodiment of the disclosure, are understood to mean that the condition or characteristic is defined to within tolerances that are acceptable for operation of the embodiment for an application for which it is intended. Wherever a general term in the disclosure is illustrated by reference to an example instance or a list of example instances, the instance or instances referred to, are by way of non-limiting example instances of the general term, and the general term is not intended to be limited to the specific example instance or instances referred to. Unless otherwise indicated, the word “or” in the description andclaims is considered to be the inclusive “or” rather than the exclusive or, and indicates at least one of, or any combination of more than one of items it conjoins.

[0024] Fig. 1A shows a sequence of photographs of a PNG robot hand 20 comprising an actuator palm 22 and a set 60 of, optionally two, PNG fingers 61 operating to grip and pick up a set of keys 100, in accordance with an embodiment of the disclosure. Fig. IB shows a sequence of two photographs of PNG robot hand 20 picking up a coin 102, in accordance with an embodiment of the disclosure. PNG fingers 61 as shown in an inset 200 in Fig. IB may be equipped with sharp fingertips 62, optionally referred to as fingernails 62, that facilitate picking up and gripping small objects such as the coin. Fig. 1C shows a photograph of PNG hand 20 gripping and drawing a wipe tissue 104 out from a wipe tissue container, in accordance with an embodiment of the disclosure.

[0025] Fig. 2A schematically shows a PNG robot hand 20 similar to that shown in Figs. 1A-1C comprising a set 60 of optionally two opposable articulated PNG fingers 61 and a PNG actuator palm 22, in accordance with an embodiment of the disclosure.

[0026] Actuator palm 22 optionally comprises a housing 24, having a top locking cap 25, a body shell 26, and a bottom mounting cup 27. Finger set 60 is mounted to body shell 26 so that fingers 61 protrude out from an opening formed in top locking cap 25, which screws onto mounting shell 26 to hold finger set 60 firmly mounted to the body shell. The fingers are coupled to an actuator (not shown in Fig. 2A) which is mounted to bottom mounting cup 27 and seats inside body shell 26 of housing 24. Details of finger set 60 are described below with respect to Fig. 2B. The actuator is shown in and discussed below with reference to Figs. 2C-3D.

[0027] Fig. 2B shows an enlarged schematic image of finger set 60 showing details of fingers 61. Each finger 61 optionally comprises an end link 62, two intermediate links 64 and 66, and a support flange 68. Adjacent links are connected by flexure springs 63. Each support flange 66 is connected to adjacent intermediate link 66 by a flexure spring 65 and includes a mounting peg 67 for connecting finger set 60 to body shell 26 (Figs. 2A, and 2C). End link 62 in each finger 61 is anchored to optionally two tendons 71 which pass through and are free to slide along their respective lengths in each intermediate link 64 and 66 of the finger. Septa 72 in intermediate links 64 and 66 are located between and separate tendons 71 that pass through the links. Each tendon 71 in a finger 61 of finger set 60 is joined to a corresponding tendon 71 in the other of fingers 61 in the finger set by a tendon join 74. In an embodiment finger set 60 and all its components are formed in a one-shot 3D printing operation, discussed below in more detail with reference to Fig. 5 and Fig. 6.

[0028] Fig. 2C schematically shows a partially exploded view of PNG robot hand 20 in which top locking cap 25 is separated from housing 24 and body shell 26 is transparent to illustrate mountingof set 60 of fingers 61 to the body shell and coupling the fingers to an activator 80. Fig. 2D schematically shows a partially exploded view of PNG robot hand 20 in which both top locking cap 25 and body shell 26 are shown separately from bottom mounting cup 27 to expose features of activator 80.

[0029] Finger set 60 is mounted to body shell 26 by inserting mounting pegs 67 (Fig. 2B) into sector slots 28 formed in the body shell and locking the finger set into place by screwing locking cap 25 onto the body shell so that internal surfaces (not shown) of the top locking cap presses down on flanges 68. In an embodiment, distance between mounting pegs 67 in finger set 60 and their respective diameters are matched to sector slots 28 so that when inserted into the sector slots the mounting pegs seat snuggly in the slots at locations where the slots have a same width as the diameter of the pegs. Pegs 67 and slots 28 operate thereby to center finger set 60 on body shell 26 and align the finger set with activator 80.

[0030] In an embodiment activator 80 comprises a reel motor 81 having a reel 82 coupled to tendon joins 74 of fingers 61 by a pull band 84 attached to the reel. Optionally, a saddle coupler 86 seats on tendon joins 74 and locks to a pull band pommel 87, (hidden by the saddle in Figs. 2C and 2D but shown in and discussed below with reference to Figs. 3A-3D) to couple pull band 84 to tendon joins 74. Reel motor 81 rotates reel 82 to reel in the pull band to elastically bend flexure springs 63 and 65 and fingers 61 to move the fingers toward each other and close PNG robot hand 20 to grip an object. The reel motor reels out the pull band to enable flexure springs 63 and 65 to straighten and move fingers 61 away from each other to open the robot hand and release the object.

[0031] Figs. 3A-3E schematically show details of features of actuator 80 and steps in the assembly and coupling of the actuator to tendon joins 74 of PNG finger tendons 71, in accordance with an embodiment of the disclosure.

[0032] Fig. 3 A schematically shows actuator 80 decoupled from tendon joins 74 to which corresponding tendons 71 are joined. The figure shows pull band 84 having a pommel 87 at an end of the pull band which is to be inserted between tendon joins 74 to connect the pull band to the joins and thereby to tendons 71. Saddle coupler 86 which locks the pommel and pull band to the tendon joins is formed having a receiving slot 88 shaped to allow the saddle to be slipped onto the pommel. Fig. 3B schematically shows pull band 84 and pommel 87 after the pull band has been inserted between and above tendon joins 74 and PNG fingers 61 manually pressed toward each other to displace tendon joins 74 sufficiently below the pommel 87 to enable saddle coupler 86 to be comfortably slipped onto and receive the pommel via receiving slot 88. Fig. 3C schematically shows saddle coupler 86 slipped onto pommel 87. Once slipped onto pommel 87, the manual force pressingPNG fingers 61 toward each other is released to allow flexure springs 63 and 65 to splay out the fingers away from each other and thereby raise tendon joins 74 so that they seat inside saddle coupler 86 on either side of pull band 84 and lock the saddle coupler to the pommel so that it cannot slide out from receiving slot 88. Fig. 3D schematically shows saddle coupler 86 locked to pommel 87 and actuator 80 coupled to and operable to open and close the fingers. Fig. 3E schematically shows a cross section view of saddle coupler 86 with tendon joins 74 on either side of pull band 87 and thereby locking the pull band and pommel 87 (not shown in Fig. 3E) to the saddle coupler 86.

[0033] In an embodiment palm 22 comprising housing 24 shown as part of PNG robot hand 20 may be modified to be attached to a set of PNG fingers having a size different form that shown in Figs. 1 A-3D by mounting to body shell 26 a piggy-back adapter.

[0034] By way of example, Fig. 4A schematically shows an exploded view of a PNG hand 120 comprising a relatively small PNG set 160 of fingers 161 having mounting pegs 167 for mounting set 160 to a palm 22 modified by a piggy-back adapter 124 and having an elongated pull bar 84. Piggyback adapter 124 comprises a turret 125 and a turret cap 126. Turret 125 comprises sector prongs 127 configured to fit into sector slots 28 formed in body shell 26 and is formed having turret slots 128 configured to receive mounting pegs 167. Elongated pull bar 84, as schematically shown in Figs. 4B and 4C, allows for pommel 87 of the pull bar to extend beyond the length of turret 125 so that the pull bar can be connected to activator 80 (Fig. 2C-3D) housed in housing 24 (Fig. 4C).

[0035] Fig. 5 shows a photograph of a PNG set 60 similar to that shown in Fig. 2B comprising two 3D-printed articulated opposable fingers 61 as they appear upon removal from a 3D-printer (not shown) that printed them, in accordance with an embodiment of the disclosure. PNG set 60 was printed in a one-step printing procedure including links 62, 64, and 66, flexure springs 63, flanges 68 and tendons 71, in which the tendons are formed in the printing process from a thermoplastic polyurethane.

[0036] Fig. 6 shows a photograph of a PNG set 260 of four 3D-printed articulated fingers 61 as they appear upon removal from a 3D-printer (not shown) that printed them, in accordance with an embodiment of the disclosure.

[0037] In the description and claims of the present application, each of the verbs, “comprise” “include” and “have”, and conjugates thereof, are used to indicate that the object or objects of the verb are not necessarily a complete listing of components, elements or parts of the subject or subjects of the verb.

[0038] Descriptions of embodiments of the disclosure in the present application are provided by way of example and are not intended to limit the scope of the disclosure. The described embodimentscomprise different features, not all of which are required in all embodiments. Some embodiments utilize only some of the features or possible combinations of the features. Variations of embodiments of the disclosure that are described, and embodiments comprising different combinations of features noted in the described embodiments, will occur to persons of the art. The scope of the invention is limited only by the claims.

Claims

CLAIMS1. A robotic hand comprising: a set of at least two fingers having at least one compliant articulated finger comprising links, joints, and at least one tendon; and an actuating palm connected to the set of finger and operable to tense and relax the at least one tendon to cause least two of the fingers to respectively grip and release an object.

2. The robotic hand according to claim 1 wherein at least two of the plurality of links are connected by a joint comprising a flexure spring.

3. The robotic hand according to any one of the preceding claims wherein the at least one tendon passes slidably through at least one of the plurality of links.

4. The robotic hand according to claim 4 wherein the at least one tendon passes slidably through all but a last one of the plurality of links.

5. The robotic hand according to any of claims 4 or 5 wherein the at least one tendon comprises two tendons.

6. The robotic hand according to claim 6 wherein the two tendons are separated by a septum inside a link through which the tendon passes.

7. The robotic hand according to any one of the preceding claims wherein the actuating palm comprises a reel motor that is connected to the at least one tendon by a pull band and reels in and reels out the pull band to respectively tense and relax the at least one tendon.

8. The robotic hand according to claim 7 wherein the plurality of fingers comprise two compliant articulated fingers.

9. The robotic hand according to claim 8 wherein the at least one tendon comprised in each finger of the two compliant articulated fingers are joined together by a tendon join.

10. The robotic hand according to claim 9 wherein the pull band is connected to the tendon join and the reel motor reels in and reels out the pull band to simultaneously tense and relax the at least one tendon in both compliant articulated fingers.

11. The robotic hand according to any of the receding claims wherein the actuating palm comprises a body shell to which the set of fingers is mounted.

12. The robotic hand according to claim 11 wherein each finger comprises a mounting peg for mounting to the body shell.

13. The robotic hand according to claim 12 wherein the body shell comprises a slot for receiving the mounting peg of each finger in the set of at least two fingers.

14. The robotic hand according to claim 12 or claim 13 wherein the actuating palm comprises a locking cap which is screwable on to the body shell to lock the set of fingers to the body shell.

15. The robotic hand according to any of the preceding claims wherein the set of at least two fingers having at least one compliant articulated finger comprising links, joints, and at least one tendon are integrally formed by a 3D printing process.

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