Dextrous robotic hand

Abstract

A mechanical hand is provided for use in grasping an object. The hand, which may be part of a robot or a human prosthetic, includes dedicated mechanisms for controlling independent finger abduction-adduction and flexion-extension motions. The compound movements made possible by the multiple drive systems in the hand improve dexterity and permit the hand to be used in applications requiring accuracy and responsiveness. The motors for the flexion¬ extension drive assemblies are attached directly to the fingers to obviate the need for intermediate linkages that can create imprecise and delayed movements.

Description

DEXTROUS ROBOTIC HANDRELATED APPLICATIONS

[0001] The present application claims the benefit of United States Provisional Patent Application Serial No. 63 / 564,613 filed March 13, 2024 and entitled, “Dextrous Robot Hand,” the disclosure of which is hereby incorporated by reference.FIELD OF THE INVENTION

[0002] This invention relates generally to the field of robotics and more particularly, but not by way of limitation, to a robotic hand.BACKGROUND

[0003] Robots are employed in a variety of fields for commercial, research, military, and other purposes. In recent years, industries such as manufacturing and commercial food processing have increasingly relied upon robotic mechanisms to automate processes with greater precision and speed than is possible by human workers alone.

[0004] Robotics designers have developed mechanisms for grasping and moving objects, either based on the real-time instructions of a manual operator or based upon pre-set programming. Some existing robots employ a clamp claw with fingers that use a pinching action to engage and pick up objects. Other robots use jointed appendages to wrap around an object and create an encompassing grip thereon.

[0005] The existing robotics mechanisms for grasping and moving objects are complicated and limited in their ability to adjust grip for objects of varying size and shapes. In many applications, the grips of these existing mechanisms must be altered through manual adjustment before the mechanism can be employed. For example, with a clamp claw, the distance of the claw fingers from a central point may need to be manually adjusted to permit the claw fingers to securely grasp objects of larger or smaller sizes. These manual adjustments can be time-intensive, costly, and unwieldy for operators. There exists a need, therefore, for a robotic grasping mechanism that can securely grasp objects of vaiying sizes and shapes without the need for time- and cost-intensive manual adjustments to the mechanism.SUMMARY OF THE INVENTION

[0006] In some embodiments, the present disclosure is directed to a robotic hand for use in grasping an object. The hand includes a base and a plurality of grasping assemblies connected to the base. The base includes a plurality of proximal joint assemblies and a plurality of abduction-adduction drive assemblies. Each of the plurality of abduction-adduction drive assemblies is connected to a corresponding one of the plurality proximal joint assemblies. Each of the plurality of grasping assemblies has a proximal portion connected to a corresponding one of the plurality of proximal joint assemblies and a proximal flexion-extension drive assembly located on the proximal portion.

[0007] In other embodiments, the present disclosure is directed to a robotic hand that includes a base and a plurality of grasping assemblies connected to the base. Each of the plurality of grasping assemblies has a proximal portion, a medial-distal flexion-extension drive assembly located on the proximal portion, a medial portion, and a distal portion. The medial portion is configured to rotate about a medial flexion-extension axis of rotation when the medial-distal flexion-extension drive assembly is activated. The distal portion is configured to rotate about a distal flexion-extension axis of rotation when the medial portion is rotated about the medial flexion-extension axis of rotation.

[0008] In yet other embodiments, the present disclosure is directed to a grasping assembly for use on a robotic hand. The grasping assembly includes a proximal portion that has a proximal body, and a distal portion that has a distal linkage, and a medial portion. The medial portion includes a medial active linkage connected to the distal linkage with a distal concentric bolt and a medial passive linkage connected to the distal linkage with a distal eccentric bolt. Thegrasping assembly further includes a medial-distal flexion-extension drive assembly located on the proximal portion. The medial portion is configured to rotate about a medial flexionextension axis of rotation when the medial-distal flexion-extension drive assembly is activated. The distal portion is configured to rotate about a distal flexion-extension axis of rotation when the medial portion is rotated about the medial flexion-extension axis of rotation.BRIEF DESCRIPTION OF THE DRAWINGS

[0009] FIG. 1 depicts a mobile robot with a dextrous mechanical hand supported by an articulating arm.

[0010] FIG. 2 depicts a stationary robot with a with a dextrous mechanical hand supported by an articulating arm.

[0011] FIGS. 3-4 provide first and second perspective views of the dextrous mechanical hand constructed in accordance with a first embodiment.

[0012] FIGS. 5A-5B provide back and exploded views, respectively, of the base of the dextrous hand of FIGS. 3-4.

[0013] FIGS. 6A-6B provide perspective and exploded views, respectively, of the distal and medial linkages of the dextrous hand of FIGS. 3-4.

[0014] FIGS. 7A-7B provide perspective and exploded views, respectively, of the distal, medial and proximal linkages of the dextrous hand of FIGS. 3-4.

[0015] FIGS. 8A-8B depict the connection of the finger assemblies connected to the base of the dextrous hand of FIGS. 3-4.WRITTEN DESCRIPTION

[0016] While this invention is susceptible to embodiment in many different forms, there are shown in the drawings and will herein be described in detail some specific embodiments of the invention. It should be understood, however, that the present disclosure is to be considered anexemplification of the principles of the invention and is not intended to limit the invention to the specific embodiments so described.

[0017] Referring now to the figures of the drawings, wherein like numerals of reference designate like elements throughout the several views, and initially to FIG. 1, a robot 100 is depicted in accordance with an exemplary embodiment. The robot 100 includes a body 102 and a mobility system 104 attached to or integrated with the body 102 to permit the robot 100 to move from one location to another. The mobility system 104 may employ a track system (as shown), wheels, legs, propellers, or other mobility mechanisms. In some embodiments, the robot 100 has a humanoid form with two or more legs and two or more arms extending away from the body 102. In the embodiment depicted in FIG. 2, the robot 100 operates from a stationary position (e.g., in an assembly line) and does not include the mobility system 104. In each case, the robot 100 further includes a plurality of sensors 106 which may include navigational and positioning sensors, velocity sensors, acceleration sensors, motor torque sensors, cameras, light sensors, range sensors, sound sensors, proximity sensors, tactile sensors, and temperature sensors.

[0018] As illustrated in FIGS. 1 and 2, the robot 100 includes an arm 108 and a hand 1 10 supported by the arm 108. The arm 108 can include articulating, extensible and retractable joints that permit the arm 108 to position the hand 110 in an operative position to grasp an object 200. In some embodiments, the hand 110 can be affixed directly to the body 102 of the robot 100.

[0019] The robot 100 of FIGS. 1 and 2 further includes an integrated electronic control system 112 which is configured to control the operation of the robot 100, including the mobility system 104 (if so equipped), the arms 108, and hands 110. For example, the control system 112 may control the speed and direction of movements made by the arms 108 and hands 110. In some embodiments, the control system 112 of the robot 100 is pre-programmed to execute one ormore specific actions in response to input received from the sensors 106. As an example, visual input from camera sensors 106 can be used by the control system 112 to position the hand 110 directly over the object 200. In other embodiments, an operator may access the control system 112 locally or remotely to provide real-time instructions for the robot 100 to perform certain actions.

[0020] Turning to FIGS. 3-4, shown therein are palmar and dorsal views, respectively, of the hand 110. The hand 110 includes a plurality of grasping assemblies 114, e.g., fingers and thumb, attached to a base 116, which can be constructed from one or more elements. A control module 118 is located inside the base 116 and is used to control the operation of the hand 110 in response to command signals received from the control system 112 or another local or remote source. The control module 118 may include one or more batteries that can be used to provide power the various motors and sensors in the hand 110. In other embodiments, electrical power is provided to hand 110 from a remote source.

[0021] As explained below, the hand 110 includes several important features not found in earlier designs. Each grasping assembly 114 includes a proximal portion 1 14a, a medial portion 1 14b and a distal portion 1 14c. The grasping assemblies 1 14 are capable of compound movements that include flexion and extension, i.e., bending the grasping assemblies 114 towards and away from the base 116, and abduction and adduction, i.e., spreading the finger assemblies 1 14 apart from one another and then returning the grasping assemblies 114 back together, or toward one another. In the embodiment depicted in FIGS. 3-4, the hand 110 includes four “finger” grasping assemblies 114 attached to the end of the base 1 16 and a single “thumb” grasping assembly 114 attached to the side of the base 116. In this way, the embodiment of the hand 110 depicted in FIGS. 3-4 closely approximates a human hand. In other embodiments, the hand 110 includes 2, 3, 5, 6, 7, 8, 9, or 10 or more grasping assemblies 114, which may be connected to the base 116 in a variety of configurations.

[0022] Additionally, the movements of the grasping assemblies 114 are driven by servo motors that are located on the grasping assemblies 114 or the base 116. The placement of the drive systems on the hand 110 eliminates the need for tendon-like straps or wires that comiect the fingers to remotely located motors. This improves the responsiveness of the hand 110, simplifies manufacturing, and reduces the overall cost of the hand 110.

[0023] Referring now also to FIGS. 5A-5B and 8A-8B, the base 116 includes a palmar plate 120, a dorsal plate 122, proximal joint blocks 124a and 124b, a plurality of abduction-adduction drive assemblies 126, and a plurality of proximal joint assemblies 128. The dorsal plate 122 and proximal joint blocks 124a, 124b can be secured to the palmar plate 120 with screws or other fasteners. The dorsal plate 122 and palmar plate 120 cooperate to contain the internal control module 118 and abduction-adduction drive assemblies 126. In some embodiments, the palmar plate 120 and dorsal plate 122 lie in planes that are more or less parallel.

[0024] Each abduction-adduction drive assembly 126 includes an abduction-adduction drive motor 130 and an abduction-adduction drive gear 132 driven by the abduction-adduction drive motor 130. Each of the abduction-adduction drive gears 132 is a beveled gear that is configured to mesh with a counterpart gear, which may be located in a different rotational plane from the abduction-adduction drive gears 132. In this way, the abduction-adduction drive gears 132 can be configured to cause a rotational movement that is offset or orthogonal to the primary plane in which the abduction-adduction drive gears 132 rotate.

[0025] For example, each proximaljoint assembly 128a, 128b includes an abduction-adduction receiver gear 134, a central pivot 136, and a proximal flexion-extension receiver gear 138. The abduction-adduction receiver gear 134 and proximal flexion-extension receiver gear 138 can each be integrated into the proximal joint assembly 128 (as shown), or presented as separate gears that are secured to the proximaljoint assembly 128. As best illustrated in FIG. 8A, each proximal joint assembly 128 is configured to rotate about the central pivot 136 in response torotation of the abduction-adduction drive gear 132 and intermeshed proximal flexion-extension receiver gear 138, which are arranged in a substantially orthogonal relationship. As the abduction-adduction drive gear 132 rotates in a clockwise direction (looking down on the abduction-adduction drive gear 132), the abduction-adduction receiver gear 134 rotates in a counterclockwise direction (looking at the abduction-adduction receiver gear 134 from the dorsal side of the hand 110). Accordingly, by rotating the abduction-adduction drive gear 132 in clockwise and counterclockwise directions, the proximal joint assembly 128 can be rotated in abduction or adduction movements.

[0026] As best illustrated in FIG. 5B, the abduction-adduction drive assembly 126b and proximal joint assembly 128b are configured such that the proximal joint assembly 128b for the “thumb” grasping assembly 114 rotates in a palmar or dorsal direction at an angular offset, i.e., a different axis of rotation, with respect to the other grasping assemblies 114. This allows the thumb grasping assembly 1 14 to be positioned on the palmar side of the hand 110 that permits the thumb grasping assembly 114 to flex inward toward the palmar plate 120, as described below.

[0027] In the depicted embodiments, each of the proximal joint assemblies 128 is captured between the palmar plate 120 and the proximal joint block 124a with an abduction-adduction bolt 140, which extends through the central pivot 136. The proximal joint block 124a shields the abduction-adduction drive assemblies 126 and stabilizes the proximal joint assemblies 128a. The proximal joint block 124b is secured directly to the palmar plate 120 with the abduction-adduction bolt 140. The proximal joint block 124b covers the abduction-adduction drive assembly 126b that controls the palmar-dorsal movement of the thumb grasping assembly 114.

[0028] Each of the proximal joint assemblies 128 is configured to rotate about a corresponding central pivot 136 along a proximal abduction-adduction axis of rotation. In some embodiments,two or more of the proximal abduction-adduction axes of rotation are more or less parallel to one another. In some embodiments, one or more of the proximal abduction-adduction axes of rotation are more or less orthogonal to a plane defined by the palmar plate 120 or to a plane defined by the dorsal plate 122. In some embodiments, the hand 110 includes a plurality of grasping assemblies 114 attached to the base 116, each with a different proximal abductionadduction axis of rotation.

[0029] Referring to FIGS. 6A-6B, shown therein are isolated depictions of the grasping assembly medial and distal portions 114b, 114c. The grasping assemblies 114 include a medial active linkage 142, a medial passive linkage 144, a fingertip 146, and a distal linkage 148. The fingertip 146 may be provided with a rubberized or other coating that increases frictional contact by the fingertip 146. The medial active linkage 142 includes a first end that includes a medial flexion-extension receiver gear 150 and a second end connected to the distal linkage 148. The medial flexion-extension receiver gear 150 can be integrated into the medial active linkage 142 (as shown), or presented as a separate gear that is secured to the medial active linkage 142. The distal linkage 148, in turn, is connected to the fingertip 146. In the depicted embodiment, the distal linkage 148 and medial active linkage 142 are connected for rotation by a distal concentric shaft 152 that passes through an approximate center of rotation of the distal linkage 148. The passive linkage 144 is connected to the distal linkage 148 with a distal eccentric bolt 154 in an offset location from the center of rotation of the distal linkage 148.

[0030] Turning to FIGS. 7A-7B, shown therein is the grasping assembly 114, illustrating the connection of the proximal portion 1 14a to the medial and distal portions 114b, 114c. The proximal portion 114a includes a proximal body 156, a medial-distal flexion-extension drive assembly 158 and a proximal flexion-extension drive assembly 160. The proximal body 156 includes two sides connected by end pieces. The proximal body 156 supports the medial-distal flexion-extension drive assembly 158 and the proximal flexion-extension drive assembly 160such that these drive assemblies are located on the grasping assembly proximal portion 114a. The medial-distal flexion-extension drive assembly 158 includes a medial-distal flexionextension drive motor 162 and a medial-distal flexion-extension drive gear 164. The proximal flexion-extension drive assembly 160 includes a proximal flexion-extension drive motor 166 and a proximal flexion-extension drive gear 168. The medial-distal flexion-extension drive motor 162 is connected to the distal portion of the proximal body 156, while the proximal flexion-extension drive motor 166 is connected to the proximal portion of the proximal body 156.

[0031] The medial active linkage 142 is connected to the proximal body 156 such that the medial-distal flexion-extension drive gear 164 engages the medial flexion-extension receiver gear 150. The medial active linkage 142 is configured to pivot about the end of the proximal body 156 with a medial concentric bolt 170 through a center of rotation of the medial active linkage 142, while the medial passive linkage 144 is connected to the proximal body 156 with a medial eccentric bolt 172 that provides an offset, i.e. , non-colinear, axis of rotation about the proximal body 156. The eccentric connection between the medial passive linkage 144 and the distal linkage 148 causes the medial passive linkage 144 to force a rotation or flexion-extension motion as the medial active linkage 142 is rotated by the medial-distal flexion-extension drive assembly 158. Thus, with a single motor, the medial portion 114b and distal portion 114c of the grasping assembly 114 are both configured to flex or extend in response to the clockwise or counterclockwise rotation of the medial-distal flexion-extension drive motor 162. The conjugate movement of the medial and distal grasping assembly portions 114b, 114c optimizes the grasping force of the hand 110 by drawing the fingertip 146 towards the object 200. Thus, the fingertip 146 and distal linkage 148 of each distal grasping portion 114c rotate about a distal flexion-extension axis of rotation, while each medial grasping portion 114b rotates about a medial flexion-extension axis or rotation.

[0032] As illustrated in FIGS. 8A-8B, the proximal body 156 is connected to the proximal joint assembly 128 with a flexion-extension bolt 174. The proximal flexion-extension drive gear 164 engages with the proximal flexion-extension receiver gear 138. In this position, the rotation of the proximal flexion-extension drive gear 164 causes the proximal flexion-extension receiver gear 138 to pivot the grasping assembly 114 in a flexion or extension motion depending on the direction of rotation of the proximal flexion-extension drive gear 168. In this way, the proximal flexion-extension drive assembly 158 forces the grasping assembly 114 to pivot about the proximal joint assembly 128 and the grasping assembly proximal portion 114a has a proximal flexion-extension axis of rotation that extends through the flexion-extension bolt 174. In some embodiments, one or more of the grasping assemblies 114 has a proximal flexion-extension axis of rotation that is about orthogonal or perpendicular to the proximal abduction-adduction axis of rotation.

[0033] Thus, using a combination of three motors, each grasping assembly 114 can be made to flex or extend while simultaneously abducting or adducting. Importantly, the grasping assembly medial and distal portions 114b, 1 14c can be flexed or extended independently of the grasping proximal portion 1 14a. Additionally, the grasping assemblies 1 14 can each be independently abducted and adducted, while simultaneously flexing or extending the grasping assembly medial and distal portions 114b, 114c. This allows the hand 110 to perform complex, maneuvers that demand a high level of dexterity and responsiveness, such as controlling a tool, playing an instrument or engaging with machine or computer interfaces designed for human interaction, e.g., keyboards, door handles, etc. In addition to its applications in the field of robotics, the hand 110 is also well suited for use as a human prosthetic.

[0034] The control module 118 can be configured to receive force feedback signals from each of the motors by monitoring changes in current draw during a movement. As the current draw increases, the control module 118 interprets the change in output as an indication that theproximal, medial or distal portion of the grasping assembly 114 has contacted an object that is opposing further movement of the grasping assembly 114. In some embodiments, the hand 110 is fitted with additional sensors for providing feedback to the control module 118, such as pressure sensors, accelerometers, proximity sensors, vibration sessors, temperature sensors, and cameras.

[0035] It is to be understood that even though numerous characteristics and advantages of various embodiments of the present invention have been set forth in the foregoing description, together with details of the structure and functions of various embodiments of the invention, this disclosure is illustrative only, and changes may be made in detail, especially in matters of structure and arrangement of parts within the principles of the present invention to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed. It will be appreciated by those skilled in the art that the teachings of the present invention can be applied to other systems without departing from the scope and spirit of the present invention.

[0036] As used herein the qualifiers "about," “more or less,” or "approximately" are intended to include not only the exact value, amount, degree, orientation, or other qualified characteristic or value, but are intended to include some slight variations, which may be due to measuring error, manufacturing tolerances, observer error, and combinations thereof, for example. The term "about" or "approximately", where used herein when referring to a measurable value such as an amount or angles, a temporal duration, and the like, is meant to encompass, for example, variations of ± 20% or ± 10%, or ± 5%, or ± 1%, or ± 0.1% from the specified value, as such variations are appropriate given the subject matter of this disclosure and as understood by persons having ordinary skill in the art.

Claims

The invention claimed is:

1. A robotic hand for use in grasping an object, wherein the hand comprises: a base, wherein the base comprises: a plurality of proximal joint assemblies; and a plurality of abduction-adduction drive assemblies, wherein each of the plurality of abduction-adduction drive assemblies is connected to a corresponding one of the plurality proximal joint assemblies; and a plurality of grasping assemblies connected to the base, wherein each of the plurality of grasping assemblies comprises: a proximal portion connected to a corresponding one of the plurality of proximal joint assemblies; and a proximal flexion-extension drive assembly located on the proximal portion.

2. The robotic hand of claim 1, wherein each of the plurality of abductionadduction drive assemblies comprises: an abduction-adduction drive motor; and an abduction-adduction drive gear.

3. The robotic hand of claim 2, wherein each of the plurality of proximal joint assemblies comprises: a central pivot; and an abduction-adduction receiver gear that engages with the abduction-adduction drive gear of a corresponding one of the plurality of abduction-adduction drive assemblies to rotate the proximal joint assembly about a proximal abductionadduction axis of rotation extending through the central pivot.

4. The robotic hand of claim 2, wherein each of the plurality of proximal joint assemblies comprises a proximal flexion-extension receiver gear.

5. The robotic hand of claim 4, wherein the proximal flexion-drive assembly of each of the plurality of grasping assemblies comprises: a proximal flexion-extension drive motor; and a proximal flexion-extension drive gear, wherein the proximal flexion-extension drive gear is engaged with the proximal flexion-extension receiver gear of a corresponding one of the plurality of proximal joint assemblies to rotate the proximal portion of the corresponding grasping assembly along a proximal flexion-extension axis of rotation.

6. The robotic hand of claim 5, wherein each of the plurality7of grasping assemblies further comprises a medial portion, wherein the medial portion is connected to the proximal portion of each grasping assembly.

7. The robotic hand of claim 6, wherein the each of the plurality of grasping assemblies further comprises a medial-distal flexion-extension drive assembly.

8. The robotic hand of claim 7, wherein the medial-distal flexion-extension drive assembly is located on the proximal portion of the corresponding one of the plurality of grasping assemblies.

9. The robotic hand of claim 7, wherein the medial portion of each of the plurality of grasping assemblies comprises: a medial active linkage that includes a medial flexion-extension receiver gear; anda medial passive linkage.

10. The robotic hand of claim 9, wherein the medial-distal flexion-extension drive assembly of each of the plurality of grasping assemblies comprises: a medial-distal flexion-extension drive motor; and a medial-distal flexion-extension drive gear, wherein the medial-distal flexionextension drive gear engages with the medial flexion-extension receiver gear on the medial portion to rotate the medial active linkage about a medial flexionextension axis of rotation.

11. The robotic hand of claim 10, wherein each of the plurality7of grasping assemblies further comprises a distal portion that comprises: a distal linkage connected to the medial active linkage and the medial passive linkage; and fingertip connected to the distal linkage.

12. The robotic hand of claim 11, wherein the medial active linkage is connected to the distal linkage with a distal concentric bolt that defines a distal flexion-extension axis of rotation.

13. The robotic hand of claim 12, wherein the medial passive linkage is connected to the distal linkage with a distal eccentric bolt that is non-colinear with the distal concentric bolt.

14. The robotic hand of claim 13, wherein the medial passive linkage is connected to the proximal portion with a medial eccentric bolt and the medial active linkage is connected to the proximal portion with a medial concentric bolt that is non-colinear with the medial eccentric bolt.

15. A robotic hand comprising: a base; a plurality of grasping assemblies connected to the base, wherein each of the plurality of grasping assemblies compnses: a proximal portion; a medial-distal flexion-extension drive assembly located on the proximal portion; a medial portion, wherein the medial portion is configured to rotate about a medial flexion-extension axis of rotation when the medial-distal flexion-extension drive assembly is activated; and a distal portion, wherein the distal portion is configured to rotate about a distal flexion-extension axis of rotation when the medial portion is rotated about the medial flexion-extension axis of rotation.

16. The robotic hand of claim 15, wherein for each of the plurality of grasping assemblies, the medial flexion-extension axis of rotation and the distal flexion-extension axis of rotation are about parallel.

17. The robotic hand of claim 15, wherein each of the plurality of grasping assemblies further comprises a proximal flexion-extension drive assembly located on theproximal portion that is configured to rotate the proximal portion about a proximal flexionextension axis of rotation.

18. The robotic hand of claim 17, wherein the base further comprises: a plurality of proximal joint assemblies, wherein each of the plurality of proximal joint assemblies is connected to the proximal portion of a corresponding one of the plurality of grasping assemblies and wherein each of the plurality of proximal joint assemblies includes an integrated abduction-adduction receiver gear; and a plurality of abduction-adduction drive assemblies, wherein each of the plurality of abduction-adduction drive assemblies is connected to a corresponding one of the plurality proximal joint assemblies and configured to rotate the corresponding proximal joint assembly about a proximal abduction-adduction axis or rotation.

19. The robotic hand of claim 19, wherein each of the plurality of abductionadduction drive assemblies comprises: an abduction-adduction drive motor; and an abduction-adduction drive gear engaged with the abduction-adduction receiver gear of a corresponding one of the plurality of proximal joint assemblies.

20. A grasping assembly for use on a robotic hand, grasping assembly comprising: a proximal portion comprising a proximal body; a distal portion comprising a distal linkage; a medial portion comprising: a medial active linkage connected to the distal linkage with a distal concentric bolt; anda medial passive linkage connected to the distal linkage with a distal eccentric bolt; and a medial-distal flexion-extension drive assembly located on the proximal portion, wherein the medial portion is configured to rotate about a medial flexionextension axis of rotation when the medial-distal flexion-extension drive assembly is activated and wherein the distal portion is configured to rotate about a distal flexionextension axis of rotation when the medial portion is rotated about the medial flexion-extension axis of rotation.

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