The monopod is a single-legged robot developed at MIT. It was developed keeping in mind the use of articulated legs. This is the monopod’s notable feature - it uses articulated legs unlike other robots that still use telescoping legs.
Through a series of investigations, the researchers at the MIT lab found out that this feature allows the monopod to execute a leaf spring unlike the air springs performed by other running robots. They found out that using articulated legs offers more mechanical advantages like lesser moment of inertia, lesser tendency for a mass not to bounce and a greater range of motion. It also allows the robot to have greater and better compression and ruggedness.
They also noted that articulated legs could be made stronger, lighter, faster and more efficient as compared to telescoping legs. Researchers still have to find a way to integrate the elastic storage elements important to excellent dynamic performance without having to make the leg too complex to use.