Legged robots at MIT: What's new since Raibert

The various techniques used for controlling the motion of legged robots are described. Low impedance electric drives were tested, but they have low torque and must run fast to deliver high power. By inserting elasticity into the actuator, and controlling the actuator's output force with a feedback loop based on the elasticity's strain, the actuator became better suited for natural tasks. Virtual motion control (VMC) algorithms were used to describe the behavior of the end-effector of a robot and a world reference frame.