Want a 20 Metre Robot to Walk? Bend the Laws of Physics

At Japan’s Yamashita Pier, about 40 Km south of Tokyo, the world’s largest humanoid robot has taken shape. Modelled on the RX-78-2 Gundam – a fictional robot that has been the subject of some 50 namesake TV series and manga since 1979 – the giant towers nearly 20 m tall and features 24° of freedom, meaning that it can move in as many directions.

- By Courtney Linder

This beast of a bot appears to be the world’s largest bipedal walking robot, and has become an iconic fixture along the Yokohama skyline. Fans began touring the exhibit, which includes an on-site museum and cafe, on 19 December 2020.

But there is dissent among faculty from some of the most prominent robotics departments in the US about whether it qualifies as a walking robot at all. Because this Gundam appears to use a supporting structure to help it move, they consider it to be a kinetic sculpture, or an art installation that relies on motion to create some affect in the viewer. Gundam Factory Yokohama, the organisation that built the robot, did not return multiple interview requests for this story.

These US-based roboticists believe that nothing short of an engineering marvel for a size to really walk, run, and wreak havoc; the law would be pushed to their logical extremes. Specifically scaling rules would dictate a whole slew of changes to the actuators (or motors) that allow the Gundam legs and take strides.

‘By scaling rules, it means that if you make bigger, then different aspects of it get bigger o different ways,’ explains Andy Ruina, PhD, a mechanical engineering at Cornell Univers School of Mechanical and Aerospace Engineering.

Scaling rules are not just the stuff of robot law predicts that the number of transistors computer chip will double every two years as th advances. Allometry, the biological study of relationship between the size of a body part of the entire body, describes why ants can haul roughly 100 times their weight and humans can’t, Ruina says.