Robotic pronator

1 . An assembly comprising:

a frame;

a motor coupled to the frame and movable with respect to the frame about a pivot axis;

a screw rotationally driven by the motor;

a nut coupled to the screw and configured to translate along the screw in response to rotation of the screw; and

a crank configured to rotate relative to the frame about an output axis; wherein the nut is coupled to the crank and configured to drive the crank about the output axis; and

a carriage positioned between the nut and the crank, wherein the carriage translates along the screw with the nut; and wherein the carriage rotates relative to the crank about a carriage axis; and

wherein the motor is movable with respect to the output axis of the crank about the pivot axis.

2 . The assembly of claim 1 , wherein the carriage is coupled to the crank at an attachment positioned a distance from the output axis.

3 . The assembly of claim 1 , further comprising a linear guide rod coupled to the motor; wherein the linear guide rod is positioned spaced from and parallel to the screw.

4 . The assembly of claim 3 , further comprising an end bracket coupled to the linear guide rod and the screw.

5 . The assembly of claim 4 , further comprising a position sensor coupled to the end bracket and configured to detect a rotational position of the screw.

6 . The assembly of claim 1 , wherein the motor includes a stator, a rotor, and a housing, wherein the stator and the rotor are at least partially received within the housing and the housing is coupled to the frame to move about the pivot axis; and wherein the rotor rotates about a screw axis of the screw.

7 . The assembly of claim 1 , wherein the motor includes a stator and the stator is coupled to the frame to move about the pivot axis.

8 . The assembly of claim 1 , wherein the crank includes:

a first end portion aligned with the output axis;

an offset portion spaced from the output axis;

a drive portion; and

a second end portion aligned with the output axis;

wherein the drive portion includes an attachment coupled to the nut.

9 . The assembly of claim 1 , wherein the frame is cylindrical shape.

10 . The assembly of claim 9 , wherein the frame includes a rim that rotationally supports the crank and a plurality of longitudinal struts that are spaced unevenly around a circumference of the rim.

11 . The assembly of claim 1 , further comprising a gearbox positioned between the motor and the screw.

12 . The assembly of claim 1 , wherein the motor is a first motor, the screw is a first screw, and the nut and the carriage are part of a first nut assembly, and wherein the assembly further comprises:

a second motor configured to rotate a second screw; and

a second nut assembly configured to translate along the second screw in response to rotation of the second screw, the second nut assembly coupled to the crank;

wherein translation of the first nut assembly along the first screw is out of phase with translation of the second nut assembly along the second screw.

13 . The assembly of claim 12 , wherein the first nut assembly is coupled to the crank at a first attachment and the second nut assembly is coupled to the crank at a second attachment; wherein the first attachment and the second attachment are spaced a distance away from the output axis; wherein an angle about the output axis is defined between the first attachment and the second attachment, and wherein the angle is within a range of 70 degrees to 130 degrees.

14 . The assembly of claim 12 , wherein the pivot axis is a first pivot axis and the second motor moves about a second pivot axis.

15 . The assembly of claim 14 , wherein the second pivot axis is colinear with the first pivot axis;

wherein the first motor moves about the first pivot axis through a first range of motion of 20.5 degrees;

wherein the second motor moves about the second pivot axis through a second range of motion of 20.5 degrees; and

wherein the first motor pivots out of phase with the second motor.

16 . The assembly of claim 12 , wherein the first screw defines a first screw axis and the first screw axis moves with respect to the output axis.

17 . The assembly of claim 12 , wherein the first screw defines a first screw axis and the first screw axis is fixed relative to the output axis.

18 . The assembly of claim 12 , wherein the first screw defines a first screw axis and the first screw axis intersects the output axis.

19 . The assembly of claim 12 , further comprising a link positioned between the first nut assembly and the crank.

20 . The assembly of claim 1 , wherein the carriage axis is spaced from and parallel to the pivot axis.

21 . The assembly of claim 20 , wherein the carriage axis is spaced from and parallel to the output axis; and wherein the frame defines a longitudinal axis; and wherein the longitudinal axis is coaxial with the output axis.

22 . The assembly of claim 1 , wherein the carriage axis is spaced from and parallel to the output axis.

23 . The assembly of claim 1 , wherein the pivot axis and the output axis are spaced apart and parallel.

24 . The assembly of claim 1 , wherein the frame is fixed relative to the output axis of the crank.

25 . The assembly of claim 1 , wherein the motor rotationally drives the screw about a screw axis; and wherein the screw axis intersects the pivot axis.

26 . The assembly of claim 25 , wherein the carriage axis is spaced from and parallel to the pivot axis; and wherein the carriage axis is spaced from and parallel to the output axis; and wherein the frame defines a longitudinal axis; and wherein the longitudinal axis is coaxial with the output axis.

27 . The assembly of claim 25 , wherein the screw axis moves with respect to the output axis.