SYSTEMS, DEVICES, AND METHODS FOR A ROBOTIC JOINT
A robotic joint has a first portion that includes a first actuator and a second actuator, a first spherical linkage having a first end mechanically coupled to the first actuator and a second end mechanically coupled to a second portion of the robotic joint, and a second spherical linkage having a third end mechanically coupled to the second actuator and a fourth end mechanically coupled to the second portion. The first and second spherical linkages are segments of a spherical shell. The first and second actuators are operable in combination to control movement of the second portion relative to the first portion with two degrees of freedom. Each actuator causes a first respective movement in the same direction as each other to control a flexion or an extension, and a second respective movement in opposite directions to each other to control an abduction or an adduction.
1 . A robotic digit comprising:
a base portion; and
a proximal portion, the proximal portion mechanically coupled to the base portion via a first robotic joint, the first robotic joint comprising:
a first portion, the first portion comprising a first actuator and a second actuator;
a first spherical linkage having a first end mechanically coupled to the first actuator and a second end mechanically coupled to a second portion of the first robotic joint, the first spherical linkage comprising a first segment of a first spherical shell; and
a second spherical linkage having a third end mechanically coupled to the second actuator and a fourth end mechanically coupled to the second portion, the second spherical linkage comprising a second segment of the first spherical shell, wherein the first actuator and the second actuator are operable in combination to control movement of the second portion relative to the first portion with two degrees of freedom.
2 . The robotic digit of claim 1 , wherein the first spherical linkage and the second spherical linkage are positioned about a center of the first spherical shell.
3 . The robotic digit of claim 1 , wherein the first actuator is a first hydraulic actuator and the second actuator is a second hydraulic actuator.
4 . The robotic digit of claim 3 , wherein the first hydraulic actuator includes a first hydraulic cylinder and a first hydraulic piston, the first hydraulic piston movable along a first longitudinal axis of the first hydraulic cylinder, and the second hydraulic actuator includes a second hydraulic cylinder and a second hydraulic piston, the second hydraulic piston movable along a second longitudinal axis of the second hydraulic cylinder, the first longitudinal axis parallel to the second longitudinal axis.
5 . The robotic digit of claim 4 , wherein the movement of the second portion relative to the first portion in a first degree of freedom of the two degrees of freedom includes a rotation about a first axis of rotation, the first axis of rotation perpendicular to the first longitudinal axis and lying in a plane that includes the first longitudinal axis and the second longitudinal axis.
6 . The robotic digit of claim 5 , wherein the movement of the second portion relative to the first portion in a second degree of freedom of the two degrees of freedom includes a rotation about a second axis of rotation, the second axis of rotation perpendicular to the first longitudinal axis and perpendicular to the plane that includes the first longitudinal axis and the second longitudinal axis.
7 . The robotic digit of claim 4 , wherein the movement of the second portion relative to the first portion in a degree of freedom of the two degrees of freedom includes a rotation about an axis of rotation, the axis of rotation perpendicular to the first longitudinal axis and perpendicular to a plane that includes the first longitudinal axis and the second longitudinal axis.
8 . The robotic digit of claim 1 , wherein at least one of the first actuator and the second actuator is a double-acting actuator.
9 . The robotic digit of claim 1 , wherein a first degree of freedom of the two degrees of freedom includes at least one of a flexion or an extension, and a second degree of freedom of the two degrees of freedom includes at least one of an abduction or an adduction.
10 . The robotic digit of claim 9 , wherein the first actuator and the second actuator each cause a first respective movement in the same direction as each other to control the at least one of a flexion or an extension, and the first actuator and the second actuator each cause a second respective movement in opposite directions to each other to control the at least one of an abduction or an adduction.
11 . The robotic digit of claim 1 , the first portion of the robotic joint comprising:
a first input ring, the first end of the first spherical linkage mechanically coupled to the first actuator via the first input ring;
a second input ring, the third end of the second spherical linkage mechanically coupled to the second actuator via the second input ring, the plane of the second input ring parallel to the plane of the first input ring; and
a first axle oriented along a first axis perpendicular to the plane of the first input ring and the plane of the second input ring, wherein the movement of the second portion relative to the first portion includes a rotation about the first axis, the rotation causing at least one of a flexion or an extension.
12 . The robotic digit of claim 11 , the first robotic joint comprising a hinge, the hinge comprising a second axle oriented along a second axis perpendicular to a plane that passes through a first longitudinal axis of the first actuator and a second longitudinal axis of the second actuator, wherein the movement of the second portion relative to the first portion includes a rotation about the second axis, the rotation causing at least one of an abduction or an adduction.
13 . The robotic digit of claim 1 , the first robotic joint comprising a hinge, the hinge comprising an axle oriented along an axis perpendicular to a plane that passes through a first longitudinal axis of the first actuator and a second longitudinal axis of the second actuator, wherein the movement of the second portion relative to the first portion includes a rotation about the axis, the rotation causing at least one of an abduction or an adduction.
14 . The robotic digit of claim 1 , the first portion further comprising a spring wherein the spring is operable to return the second portion to a baseline relative configuration of the first and the second portion.
15 . The robotic digit of claim 14 , wherein the baseline relative configuration includes at least approximately zero flexion, at least approximately zero extension, at least approximately zero abduction, and at least approximately zero adduction of the robotic joint.
16 . The robotic digit of claim 1 , further comprising a passage to accommodate at least one of an electrical wire or a hydraulic hose that passes from the first portion to the second portion.
17 . The robotic digit of claim 1 , further comprising a passage, and at least one of an electrical wire or a hydraulic hose that passes from the first portion to the second portion via the passage.
18 . The robotic digit of claim 1 , wherein the robotic digit is a finger of a humanoid robot, the base portion is a metacarpal, the proximal portion is a proximal phalange, and the first robotic joint is a metacarpophalangeal (MCP) joint.
19 . The robotic digit of claim 1 , further comprising a distal portion, the distal portion mechanically coupled to the proximal portion via a second robotic joint, the second robotic joint comprising:
a third portion, the third portion comprising a third actuator and a fourth actuator;
a third spherical linkage having a fifth end mechanically coupled to the third actuator and a sixth end mechanically coupled to a fourth portion, the third spherical linkage comprising a third segment of a second spherical shell; and
a fourth spherical linkage having a seventh end mechanically coupled to the second actuator and an eighth end mechanically coupled to the fourth portion, the fourth spherical linkage comprising a fourth segment of the second spherical shell, wherein the third actuator and the fourth actuator are operable in combination to control movement of the fourth portion relative to the third portion with two degrees of freedom.
20 . The robotic digit of claim 19 , wherein the robotic digit is a finger of a humanoid robot, the base portion is a metacarpal, the proximal portion is a proximal phalange, the distal portion is a middle phalange, the first robotic joint is a metacarpophalangeal (MCP) joint, and the second robotic joint is a proximal interphalangeal (PIP) joint.