A “cheetah” robot designed by MIT researchers may soon outpace its animal counterparts in running efficiency. In treadmill tests, the researchers have found that the robot - about the size and weight of an actual cheetah - wastes very little energy as it trots continuously for up to an hour and a half at 8 kph.

The key to the robot’s streamlined stride is its lightweight electric motors, set into its shoulders, that produce high torque with very little heat wasted.

The motors can be programmed to quickly adjust the robot’s leg stiffness and damping ratio - or cushioning - in response to outside forces such as a push, or a change in terrain. The researchers will present the efficiency results and design principles for their electric motor at the International Conference on Robotics and Automation in May.

Sangbae Kim from Massachusetts Institute of Technology’s Department of Mechanical Engineering, says achieving energy-efficiency in legged robots has proven extremely difficult.