Humanoid Robotics

A wheel never falls over on its own

A wheeled robot has a huge, boring advantage: it is always touching the ground across a wide, stable base. Push it sideways and it rolls or tips slightly, but it does not collapse. A warehouse robot with four wheels can stop dead in the middle of a task and just sit there indefinitely, stable, no computation required.

A humanoid robot has none of that for free. Standing on two feet means the robot's entire mass is balanced on a support area not much bigger than two shoe soles. Every joint from the ankle up affects whether the robot stays upright, and gravity is actively working against it every millisecond it's powered on. Humanoid engineers aren't just building a robot that moves, they're building one that has to actively fight to not fall down.