Microsurgical tool for robotic applications
The disclosed technology includes improved microsurgical tools providing multiple degrees of freedom at the wrist level, including roll, pitch, and grasp DOFs, a tight articulation bending radius, low radial offset, and improved stiffness. Some implementations include an end effector platform moveable along a fixed trajectory on a fictional axle so as not to interfere with a central-axis aligned working channel; a crossed-arm mechanical linkage for articulating an end-effector platform throughout a pitch DOF with an amplified pitch angle; and a partial pulley system to articulate the arms while maximizing pulley radius to shaft diameter, and permitting a constant transmission efficiency to the arms throughout the range of articulation. In some implementations, a tool shaft outer diameter may be smaller than 3 mm; a pitch DOF range may be ±90°, a roll DOF range may be ±180°, and a grasp DOF range may be 30°.
1. A microsurgical tool, comprising:
an elongated body having a distal end;
a platform moveably coupled to the distal end of the elongated body; and
a linkage coupling the distal end of the elongated body to the platform to allow the platform to move relative thereto, wherein the linkage comprises:
a first arm directly operatively coupled to the distal end of the elongated body at a first proximal hinge and to the platform at a first distal hinge, the first arm having a first redirect surface,
a first force transfer element disposed around the first redirect surface before terminating at the first arm such that pulling the first force transfer element pivots the first arm about the first proximal hinge with a first amplified range of motion,
a second arm directly operatively coupled to the distal end of the elongated body at a second proximal hinge and to the platform at a second distal hinge, the second arm having a second redirect surface, and
a second force transfer element disposed around the second redirect surface before terminating at the second arm such that pulling the second force transfer element pivots the second arm about the second proximal hinge with a second amplified range of motion.
2. The microsurgical tool of claim 1 , wherein the first and second arms are crossed with respect to one another.
3. The microsurgical tool of claim 1 , wherein the first and second arms form a mechanical linkage for moving the first arm with a constant transmission efficiency between the mechanical linkage and the first arm throughout a range of movement of the first arm.
4. The microsurgical tool of claim 1 , wherein the first and second amplified ranges of motion are of the same magnitude in opposite directions.
5. The microsurgical tool of claim 1 , wherein the first proximal hinge and the second proximal hinge are co-axial.
6. The microsurgical tool of claim 1 , wherein the first distal hinge and the second distal hinge are coupled to diametrically opposite positions on the platform.
7. The microsurgical tool of claim 1 , wherein the first force transfer element comprises a pull wire.
8. The microsurgical tool of claim 1 , wherein the first force transfer element and the first redirect surface of the first arm form a partial pulley to provide the first amplified range of motion.
9. The microsurgical tool of claim 1 , wherein the first amplified range of motion is in a pitch degree of freedom.
10. The microsurgical tool of claim 1 , wherein the first redirect surface of the first arm comprises a first semicircular portion.
11. The microsurgical tool of claim 10 , wherein the first semicircular portion is concentric with the first proximal hinge.
12. The microsurgical tool of claim 1 , wherein the first force transfer element is coupled to a first bore of the first arm, wherein the first bore is offset from a first line formed between the first proximal hinge and the first distal hinge.
13. The microsurgical tool of claim 1 , further comprising an end effector operatively coupled to the platform.
14. The microsurgical tool of claim 13 , wherein the end effector comprises a grasper.
15. The microsurgical tool of claim 13 , wherein the end effector comprises at least one jaw, and further comprising a first tendon coupled to the at least one jaw and tensionable to move the at least one jaw, providing the at least one jaw with a grasping degree of freedom.
16. The microsurgical tool of claim 15 , wherein the tendon is disposed at least partially within the elongated body.
17. The microsurgical tool of claim 13 , further comprising a torque coil operatively coupled to the end effector to provide the end effector with a roll degree of freedom.
18. The microsurgical tool of claim 17 , wherein one or more of the elongated body and the platform comprise a channel through which the torque coil is disposed.
19. The microsurgical tool of claim 1 , wherein the elongated body has a centerline, and wherein the first proximal hinge is offset from the centerline.
20. A microsurgical tool, comprising:
an elongated body having a distal end;
a platform moveably coupled to the distal end of the elongated body; and
a linkage coupling the distal end of the elongated body to the platform to allow the platform to move relative thereto, wherein the linkage comprises:
a first arm directly operatively coupled to the distal end of the elongated body at a first proximal hinge and to the platform at a first distal hinge, the first arm having a first redirect surface,
a first pull wire disposed around the first redirect surface before terminating at the first arm such that pulling the first pull wire pivots the first arm about the first proximal hinge with a first amplified range of motion,
a second arm directly operatively coupled to the distal end of the elongated body at a second proximal hinge and to the platform at a second distal hinge, the second arm having a second redirect surface, and
a second pull wire disposed around the second redirect surface before terminating at the second arm such that pulling the second pull wire pivots the second arm about the second proximal hinge with a second amplified range of motion.