Robotic leg
A robotic leg includes a hip, a first pulley attached to the hip and defining a first axis of rotation, a first leg portion having a first end portion and a second end portion, a second pulley rotatably coupled to the second end portion of the first leg portion and defining a second axis of rotation, a second leg portion having a first end portion and a second end portion, and a timing belt trained about the first pulley and the second pulley for synchronizing rotation of the first leg portion about the first axis of rotation and rotation of the second leg portion about the second axis of rotation. The first end portion of the first leg portion is rotatably coupled to the hip and configured to rotate about the first axis of rotation. The first end portion of the second leg portion is fixedly attached to the second pulley.
1. A robotic leg assembly comprising:
a hip;
a first pulley attached and rotationally fixed relative to the hip and defining a first axis of rotation;
a first leg portion having a first end portion and a second end portion, the first end portion of the first leg portion rotatably coupled to the hip and configured to rotate about the first axis of rotation;
a second pulley rotatably coupled to the second end portion of the first leg portion, the second pulley defining a second axis of rotation;
a second leg portion having a first end portion and a second end portion, the first end portion of the second leg portion attached and rotationally fixed relative to the second pulley; and
a timing belt trained about the first pulley and the second pulley for synchronizing rotation of the first leg portion about the first axis of rotation and rotation of the second pulley about the second axis of rotation,
wherein rotation of the first leg portion about the first axis of rotation causes rotation of the second leg portion relative to the first leg portion about the second axis of rotation.
2. The robotic leg assembly of claim 1 , wherein the first leg portion defines a longitudinal axis, the first axis of rotation is perpendicular to the longitudinal axis, and the second axis of rotation is perpendicular to the longitudinal axis.
3. The robotic leg assembly of claim 1 , wherein the first axis of rotation is parallel to the second axis of rotation.
4. The robotic leg assembly of claim 1 , wherein the first pulley and the second pulley are sized to cause a 2:1 ratio of the rotation of the second leg portion about the second axis of rotation to the rotation of the first leg portion about the first axis of rotation.
5. The robotic leg assembly of claim 1 , wherein the first pulley has 60 teeth and the second pulley has 30 teeth.
6. The robotic leg assembly of claim 1 , wherein:
the first leg portion defines:
a proximal end at the first end portion of the first leg portion;
a distal end at the second end portion of the first leg portion; and
a first length between the proximal end of the first leg portion and the distal end of the first leg portion,
the second leg portion defines:
a proximal end at the first end portion of the second leg portion;
a distal end at the second end portion of the second leg portion; and
a second length between the proximal end of the second leg portion and the distal end of the second leg portion, and
the first length is substantially equal to the second length.
7. The robotic leg assembly of claim 1 , further comprising a rotary motor arranged to drive rotation of the first leg portion about the first axis of rotation.
8. The robotic leg assembly of claim 7 , wherein the rotary motor defines a rotary axis, and the rotary axis is arranged coincident with the first axis of rotation.
9. The robotic leg assembly of claim 8 , wherein the rotary motor comprises:
a rotor arranged to rotate about the rotary axis, the rotor attached to the first leg portion; and
a stator arranged concentrically around the rotor.
10. The robotic leg assembly of claim 1 , further comprising a linear actuator disposed on the hip and having a translatable actuator arm pivotally coupled to the first leg portion, wherein actuation of the translatable actuator arm of the linear actuator causes rotation of the first leg portion about the first axis of rotation.