Georgia Tech researchers have created what they say is the most efficient-walking humanoid ever created. While most current machines are hunched at the waist and plod along on flat feet, their DURUS robot strolls like a person. It lands on the heel of its foot, rolls through the step, and pushes off its toe. DURUS is outfitted with a pair of size-13 shoes as it walks under its own power on a treadmill in the team’s AMBER Lab. The robot is further equipped with springs between its ankles and feet, similar to elastic tendons in people, allowing for a walking gait that stores mechanical energy from a heel strike to be later reclaimed as the foot lifts off the ground. This natural gait makes DURUS very efficient. Robot locomotion efficiency is universally measured by a “cost of transport,” or the amount of power it uses divided by the machine’s weight and walking speed. Some of today’s best humanoids are approximately 3.0 whereas DURUS’s cost of transport is 1.4, all while being self-powered.