Boston Dynamics took the feet off its electric Atlas humanoid and bolted scooter wheels to its ankles. In a video released November 9, Atlas skates backwards, cuts sideways and jumps, spins once and lands on both wheels. The wheels are there to put a steady load on the motors that normally move its feet.

The team fitted off-the-shelf scooter rims to the existing ankle actuators using a custom adapter. “A wheeled Atlas isn’t a product. It’s a research testbed,” wrote Atlas controls engineer Xiaoyu (Andy) Wu. Driving on wheels lets the team keep the motors under load as they accelerate, turn and brake.

What Atlas learned on wheels

In simulation, the team modeled each wheel as an ankle joint that could turn continuously. For some moves, Wu started with motion capture of people sliding their feet. The controller found a way to do a side dash by steering and rolling through the move.

The spin jump followed a recording of a person doing the same jump. Wu says Atlas landed it on the first try. In the footage, the lower body rolls into position before the robot pushes off.

Boston Dynamics says it is already applying lessons from the experiment to Atlas with its feet back on. The test gave the team a way to compare what the simulator expected from the motors with what the hardware could deliver.