Abstract
Disclosed herein is a knee joint assembly including a first link member having a first end mechanically coupled to an upper leg of a robot and configured to rotate around a first pivot relative to the upper leg, and a second link member having a first end mechanically coupled to a lower leg of the robot. The lower leg can be mechanically coupled to the upper leg and configured to rotate around a second pivot relative to the upper leg. A linear actuator device can be mechanically coupled to a second end of the first link member and a second end of the second link member, and when actuated can cause the first link member to rotate around the first pivot relative to the upper leg of the robot and cause the leg to rotate around the second pivot relative to the upper leg.