ROBOTIC DEVICE WITH COMPACT JOINT DESIGN AND AN ADDITIONAL DEGREE OF FREEDOM AND RELATED SYSTEMS AND METHODS
The embodiments disclosed herein relate to various robotic and/or in vivo medical devices having compact joint configurations and at least three degrees of freedom. Other embodiments relate to various medical device components, including forearms having grasper or cautery end effectors, that can be incorporated into certain robotic and/or in vivo medical devices.
1 . A robotic device comprising:
a) an elongate device body comprising a first driveshaft, a second driveshaft, and a third driveshaft nested coaxially within one another and independently rotatable;
b) a compact shoulder joint disposed at a distal end of the elongate device body, the compact shoulder joint comprising:
i) a conversion body coupled to at least one of the first, second, or third driveshafts;
ii) a rotation body rotatable relative to the conversion body;
iii) a differential coupling operably connecting the conversion body and the rotation body to both the first and third driveshafts such that coordinated rotation of the first and third driveshafts in a same rotational sense causes rotation of the conversion body about an axis generally parallel to a longitudinal axis of the elongate device body and coordinated rotation of the first and third driveshafts in opposite rotational senses causes rotation of the rotation body about an axis generally transverse to the longitudinal axis of the elongate device body; and
iv) an output member driven by the second driveshaft through a gear train; and
c) an arm coupled to the compact shoulder joint,
wherein the conversion body axis, rotation body axis, and output member axis intersect at a single point within the compact shoulder joint to provide three intersecting degrees of freedom for the arm.
2 . The robotic device of claim 1 , wherein the output member is an output bevel gear rotatable about an axis generally parallel to the longitudinal axis of the elongate device body.
3 . The robotic device of claim 1 , wherein a plurality of motors configured to drive the first, second, and third driveshafts are disposed in a proximal portion of the elongate device body
4 . The robotic device of claim 3 , wherein the plurality of motors being disposed in the proximal portion of the elongate device body result in a minimal radial dimension of the compact shoulder joint.
5 . The robotic device of claim 1 , further comprising absolute position sensors operably coupled to at least two of the first, second, or third driveshafts.
6 . The robotic device of claim 1 , wherein the compact shoulder joint comprises a yoke body having a yoke shaft with a longitudinal axis transverse to the longitudinal axis of the elongate device body, the rotation body being rotatable about the yoke shaft.
7 . The robotic device of claim 1 , wherein the compact shoulder joint comprises a shoulder housing configured to yaw about the longitudinal axis of the elongate device body in response to rotation of the first driveshaft.
8 . The robotic device of claim 1 , wherein the output member is configured to transmit torque through the arm to an elbow joint such that rotation of the output member actuates bending of the elbow joint.
9 . The robotic device of claim 1 , wherein the elongate device body comprises right and left compact shoulder joints and two nested driveshaft sets disposed in mirror symmetry in the elongate device body.
10 . An end effector interface comprising:
a) a coupling structure sized to couple to a forearm of a robotic arm, the coupling structure comprising a quick-release locking collar having locking protrusions mateable with notches in the coupling structure to retain an end effector with a twist-lock action;
b) a first rotatable drive member configured to transmit rotational motion to rotate the end effector; and
c) a second rotatable drive member nested within the first rotatable drive member, wherein the second rotatable drive member is configured to transmit rotational motion to actuate end effector graspers.
11 . The end effector interface of claim 10 , further comprising first and second sealing rings positioned to fluidically seal the coupling structure to the first rotatable drive member and to fluidically seal the first rotatable drive member to the second rotatable drive member.
12 . The end effector interface of claim 10 , further comprising an electrical contact spring positioned in a proximal lumen of the second rotatable drive member and configured to couple to a cautery wire accessible via a cautery wire opening in a forearm body. (New) The end effector interface of claim 10 , further comprising:
a) two motors disposed within the forearm and operably coupled via drive gears to the first rotatable drive member and the second rotatable drive member; and
b) a locking structure configured to frictionally retain the motors in position within the forearm.
14 . A method of operating a compact shoulder joint of a robotic device having first, second, and third driveshafts nested coaxially within an elongate device body, a conversion body, a rotation body, and an output member, the method comprising:
rotating the first and third driveshafts in a same rotational sense to yaw the conversion body about a longitudinal axis of the elongate device body;
rotating the first and third driveshafts in opposite rotational senses to pitch the rotation body about a transverse axis; and
driving the second driveshaft to rotate the output member about an axis generally parallel to the longitudinal axis of the elongate device body.
15 . The method of claim 14 , further comprising transmitting rotation of the output member through an upper arm gear train to actuate bending of an elbow joint positioned along a length of a forearm spaced from a proximal end of the forearm.
16 . The method of claim 14 , further comprising selectively counteracting coupled motion by coordinated control of the first and third driveshafts to nullify secondary rotation of the output member when a pure pitch or yaw is desired.
17 . The method of claim 14 , further comprising sensing absolute positions of at least two of the first, second, or third driveshafts and controlling motors positioned proximally along the elongate device body to reduce a radial dimension of the compact shoulder joint while maintaining three intersecting degrees of freedom at a single point within the compact shoulder joint.