End effectors for robotic systems

Abstract

An end effector for a robotic system, comprising: a) a first member; and b) a second member, the second member including: i) two compliant structures (101, 102), each with a living hinge; ii) a rigid bottom beam (105) for connecting to tendons; and iii) a pivot point (106) contacting the first member, the second member housed within the first member, and actuated by tension in the tendons to move the second member at the pivot point (106) and flex the two compliant structures (101, 102) at the living hinges.

Description

[Technical Field]

[0001] The present invention relates generally to end effectors for robotic systems, and more particularly to compliant grippers for robotic manipulators. [Background technology]

[0002] Gastric cancer and colorectal cancer are common worldwide and are the leading causes of cancer death worldwide. Minimally invasive surgery is widely used to evaluate diseases and injuries without requiring large incisions during surgery. Among these, endoscopic submucosal dissection (ESD) and endoscopic mucosal resection (EMR) are well-developed for removing precancerous and early-stage cancers in the GI tract. These procedures are performed using a flexible endoscope, allowing patients to recover faster with less pain.

[0003] With the recent rapid development of endoscopic surgical platforms, the development of articulated end-effectors for novel handheld robotic tools has become even more important to this emerging field of medical robotics. With current handheld design configurations, handling the gastric fundus resection is challenging because the end-effector enclosure interferes with the retroflex (J-shaped bend) of the overtube. Furthermore, due to the characteristics of the working environment, there are significant limitations on the geometry and size of the end-effector. The development of a reliable endoscopic manipulator has long been a challenging task.

[0004] Compliant grippers have excellent mechanical properties, including a compliant beam in the gripping jaw, an elastic mechanism that provides the necessary flexibility when undergoing elastic deformation. This design allows them to manipulate the XY plane and precisely grasp the target object. Furthermore, a passively compliant underactuated mechanism is one way that the gripper can accommodate irregular objects with arbitrary shapes and surface characteristics. The jaws can grasp delicate objects without damaging tissue, improving safety during surgery.

[0005] The purpose of underactuation is to optimize the gripper mechanism to control more degrees of freedom with fewer active inputs when driving the gripper's opening and closing movements. Another purpose of underactuation is to simplify the algorithm by reducing the control variables. Aside from reducing the required control complexity, this change also reduces the inflexibility of the robot arm when bending. Summary of the Invention

[0006] The present invention provides an end effector for a robotic system. In one embodiment, the end effector for a robotic system includes: a) a first member; and b) a second member, the second member including: i) two compliant structures, each with a living hinge; ii) a rigid bottom beam for connecting to tendons; and iii) a pivot point contacting the first member, the second member housed within the first member, wherein tensioning of the tendons operates to move the second member at the pivot point and flex the two compliant structures at the living hinges. [Brief explanation of the drawings]

[0007] Exemplary, non-limiting embodiments of the present invention are described below with reference to the accompanying drawings. The drawings are illustrative and generally not to scale. Identical or similar elements on different drawings are referred to with the same reference numerals.

[0008] [Figure 1A] 1A-1D illustrate various embodiments of gripper structures for robotic manipulators. [Figure 1B] 1A-1D illustrate various embodiments of gripper structures for robotic manipulators. [Figure 1C] 1A-1D illustrate various embodiments of gripper structures for robotic manipulators. [Figure 1D] 1A-1D illustrate various embodiments of gripper structures for robotic manipulators. [Figure 1E] 1A-1D illustrate various embodiments of gripper structures for robotic manipulators. [Figure 1F] 1A-1D illustrate various embodiments of gripper structures for robotic manipulators. [Figure 1G] 1A-1D illustrate various embodiments of gripper structures for robotic manipulators. DETAILED DESCRIPTION OF THE INVENTION

[0009] The present invention relates to an end effector for a robotic system to achieve gripping of an object through the implementation of a compliant mechanism.

[0010] Described herein is a compliant gripper structure with a living hinge for use as an end effector in a robotic system. The structure is normally closed when the gripper is gripping an object so that the rigidity of the robot arm and overtube is not affected. The opening action is controllable by adjusting the tension of the tendons.

[0011] In one embodiment, the present invention provides a gripper structure for a robotic manipulator, the gripper structure comprising an open-ended cylinder housing and a compliant gripper. The jaws are attached to a compliant beam capable of securely gripping tissue. The device can be mounted on a flexible robotic arm. The device is underactuated, reducing the number of tendons during actuation of the end effector and reducing stiffness during bending.

[0012] The present invention provides a structure for a gripper to be used in a robotic system. In one embodiment, the structure includes a first member that is cylindrical and serves as a platform for mounting a second member, two second members each consisting of at least one compliant segment that undergoes elastic deformation during operation of the gripper, a rigid segment connected to each of the compliant segments that does not intentionally deform during operation of the gripper, the gripper being normally closed and the gripper being opened by pulling at least one wire attached to the rigid segment.

[0013] In one embodiment, the structure further comprises at least one revolute joint interconnecting the compliant segment and the rigid segment.

[0014] In one embodiment, the structure further comprises an anchor for securing the wire to the rigid segment.

[0015] In one embodiment, the opening angle of the grippers is proportional to the pulling force applied to the wire.

[0016] In one embodiment, the structure further comprises a pivot on the cylindrical member that coincides with the revolute joint of the compliant segment.

[0017] In one embodiment, the structure further comprises a metal piece that passes through the pivot and revolute joint to maintain the member in place.

[0018] In one embodiment, the first and second members are made of plastic.

[0019] In one embodiment, the second member is diamond shaped.

[0020] In one embodiment, each compliant segment has a length-to-width ratio and a length-to-thickness ratio greater than 1, and the thickness of the bottom stiff segment is greater than the thickness of the compliant segment.

[0021] In one embodiment, the first member is an open-ended cylinder with two identical tongues on a flat surface.

[0022] In one embodiment, the structure further comprises a lead-in feature that is in contact with the groove in the bottom rigid segment and limits the angle of rotation.

[0023] In one embodiment, the compliant segments comprise living hinges.

[0024] In one embodiment, the rigid segment comprises a groove.

[0025] In one embodiment, the present invention provides an end effector for a robotic system, comprising: a) a first member; and b) a second member, the second member including: i) two compliant structures, each with a living hinge; ii) a rigid bottom beam for connecting to tendons; and iii) a pivot point contacting the first member, the second member housed within the first member, wherein pulling on the tendons operates to move the second member at the pivot point and to bend the two compliant structures at the living hinges.

[0026] In one embodiment, the first member includes a lead-in feature (110) that is in contact with a groove (109) in the rigid bottom beam (105) and limits the angle of rotation.

[0027] In one embodiment, the second member comprises: a) a first jaw comprising one of the two compliant structures, the rigid bottom beam, and a first revolute joint; and b) a second jaw attached to the first jaw, the second jaw comprising one of the two compliant structures and a second revolute joint, the first revolute joint and the second revolute joint being coupled to form the pivot point.

[0028] In one embodiment, the first member includes a hole for inserting a pin that passes through the second member to form the pivot point.

[0029] In one embodiment, each of the two compliant structures comprises a compliant beam (104) and a top compliant segment (107).

[0030] In one embodiment, the second member is diamond-shaped, where a) the top compliant segment is hairpin-shaped and has two ends, the top compliant segment connecting to the pivot point at one of the ends and to the compliant beam at the other of the ends, and b) the compliant beam has two ends, the compliant beam connecting to the rigid bottom beam at one of the ends and the top compliant segment at the other of the ends.

[0031] In one embodiment, the first member is an open-ended cylinder having two identical tongues.

[0032] In one embodiment, the living hinge is curved.

[0033] In one embodiment, the tendons are connected to hollow metal pieces at the rigid bottom beam and pass through the first member.

[0034] In one embodiment, each compliant structure comprises a length-to-width ratio and a length-to-thickness ratio greater than 1, and the rigid bottom beam comprises a thickness greater than each compliant structure.

[0035] The present invention provides a gripper structure for a robotic manipulator. In one embodiment, the gripper structure for a robotic manipulator is a grasping or retraction device for robotic endoscopic surgery, and includes a first member having a hollow cylindrical housing opening (100), as depicted in FIG. 1A. The second member has two separable compliant structures (101), (102), a gripper segment interconnecting top and middle revolute joints (103), and a compliant beam (104) interconnecting a rigid bottom beam (105). FIG. 1C shows the right jaw being pulled onto the compliant beam. FIG. 1D shows the left jaw being pulled onto the compliant beam and positioned opposite the right jaw. The three individual components are assembled by a metal pin, and the pivot point (106) of the second member is located on the first member. The tendons contact anchors for fixing to the bottom beam (105), tension is applied to the bottom rigid beam, and the first members are arranged to open and close in response to the force applied through the tendons, and the bottom rigid beam (105) is carried backward along the guide of the contacting first member.

[0036] In one embodiment, the first member and the second are made of a plastic material.

[0037] In one embodiment, the second member is diamond-shaped, with top compliant segments (107) interconnected with intermediate revolute joints (103), the top compliant segments being coupled to bottom rigid beams, each compliant segment having a width and a relatively thin thickness depending on its material properties, and the bottom rigid beam being thicker than the compliant segments.

[0038] In one embodiment, the first member is an open-ended cylinder with two identical tongues (108) on a flat surface.

[0039] In one embodiment, the tendons are secured to hollow metal pieces at the bottom rigid beam (105) and threaded through a circular housing.

[0040] In one embodiment, the compliant beam comprises a living hinge (111).

[0041] In one embodiment, the rigid beam comprises a groove (109) that is a curved surface.

[0042] In one embodiment, the revolute joint is a torus.

[0043] In one embodiment, the living hinge (111) is curved.

[0044] In one embodiment, the tongue includes a lead-in feature (110) that is in contact with a groove in the bottom rigid segment and limits the angle of rotation.

Claims

1. 1. An end effector for a robotic system, comprising: a. a first member; b. a second member, i. two compliant structures, each with a living hinge; ii. A rigid bottom beam for connecting to the tendons; iii. A pivot point that contacts the first member a second member comprising: wherein the second member is housed within the first member and tensioning of the tendons operates to move the second member at the pivot point and to bend the two compliant structures at the living hinge.

2. The end effector of claim 1 , wherein the first member comprises a lead-in feature (110) that is in contact with a groove (109) in the rigid bottom beam (105) to limit the angle of rotation.

3. The second member is a. a first jaw comprising one of the two compliant structures, the rigid bottom beam, and a first revolute joint; b. a second jaw attached to the first jaw, the second jaw comprising one of the two compliant structures and a second revolute joint; The end effector of claim 1 , comprising: a first revolute joint and a second revolute joint coupled to form the pivot point.

4. The end effector of claim 1 , wherein the first member includes a hole for inserting a pin through the second member to form the pivot point.

5. The end effector of claim 1 , wherein each of the two compliant structures comprises a compliant beam (104) and a top compliant segment (107).

6. the second member is diamond-shaped; a. the top compliant segment is hairpin shaped and has two ends, the top compliant segment connecting to the pivot point at one of the ends and connecting to the compliant beam at the other of the ends; 6. The end effector of claim 5, wherein the compliant beam comprises two ends, the compliant beam connecting the rigid bottom beam at one of the two ends and the top compliant segment at the other of the two ends.

7. The end effector of claim 1 , wherein the first member is an open-ended cylinder having two identical tongues.

8. The end effector of claim 1 , wherein the living hinge is curved.

9. The end effector of claim 1 , wherein the tendons are connected to hollow metal pieces at the rigid bottom beam and pass through the first member.

10. The end effector of claim 1 , wherein each compliant structure comprises a length-to-width ratio and a length-to-thickness ratio greater than 1, and the rigid bottom beam comprises a thickness greater than each compliant structure.

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