The average person has up to 4 million sweat glands acting as the body’s coolant system to protect it from overheating. However, humans aren’t the only things that can overheat. Machines, particularly humanoid robots, also generate heat as they perform tasks. Unfortunately, robots have never had the capacity to sweat it out like humans do — until now.

To combat this heat-generating problem, engineers typically use mechanical systems like fans and radiators. This kind of cooling infrastructure, unfortunately, takes up space and adds mass to a machine.

However, at last month’s IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS), Japanese researchers introduced a novel way to cool humanoid robots much more efficiently. They suggested that engineers design these robots to be able to sweat water out of their “bones.”

Led by Professor Masayuki Inaba from the University of Tokyo’s JSK Lab, the team of researchers had been trying to figure out a way to add a cooling system to their musculoskeletal humanoid robot named Kengoro. There was simply no room for all the tubes, fans, and radiators among all of Kengoro’s other structural components, gears, motors, and circuit boards. Instead of adding more mass to the five-and-a-half-foot, 123-pound robot, the researchers came up with the idea of using the metal frame as a coolant-delivery system.

If the researchers had simply run water channels through the frame, they would have still needed a radiator. This would not have solved their problem. Instead, they let the water seep out through the metal frame and around the motors to cool them by evaporation.

Basically, Kengoro sweats.

With just one cup of deionized water, Kengoro can function for a whole day. In fact, the robot can do push-ups for 11 minutes straight without overheating its motors. Just like humans, however, Kengoro needs to stay hydrated.

“Usually the frame of a robot is only used to support forces,” said the lead author of the study, Toyotaka Kozuki. “Our concept was adding more functions to the frame, using it to transfer water, release heat, and at the same time support forces.”