Optimus leg actuators move the Tesla Roadster's wing, according to a Tesla executive

Tesla uses Optimus leg actuators, which produce high torque, to move the Roadster's rear wing. A mechanical brake is added. According to the article, the wing switches within milliseconds from a setting that presses the car to the ground to one that reduces air resistance, and it stays locked despite the force of the wind.

The reason given is simple. At 200 mph, the wing is subject to forces of several thousand newtons, and the small motors of an ordinary car cannot move it quickly under such a load.

These actuators have a second use. They also open and close the high-pressure valves of the car's propulsion system, which must therefore control its gas jets precisely.

According to the article, this propulsion system was developed with SpaceX. It burns no fuel: high-pressure gas escapes through nozzles and pushes the car by reaction.

For Liangziwei, the choice makes sense. The leg joints of a humanoid must absorb heavy shocks when the robot walks or jumps. They are therefore powerful, compact and able to react within milliseconds.