What is a humanoid robot?

A humanoid robot is a robot built in the shape of a person: typically a torso, a head, two arms and two legs. The idea is simple. The world is designed for human bodies, so a robot with a human shape can work in our spaces and use our tools.

What's inside

• Actuators (the "muscles"): most humanoids use electric motors. Some earlier designs used hydraulics, which are powerful but bulky. Boston Dynamics retired its hydraulic Atlas in 2024 and moved to an electric version.
• Sensors: internal sensors (accelerometers, tilt and force sensors) help the robot know its own position and balance. External sensors (cameras, microphones, touch arrays) let it perceive the world around it.

Notable examples

• Honda ASIMO (2000), an early milestone that could walk and run
• Boston Dynamics Atlas, relaunched as an electric robot in 2024
• Tesla Optimus, in development since 2022
• Figure AI, which has put robots to work at a BMW plant
• Unitree G1 (2024), a lower-cost humanoid starting around $16,000

The hard parts

• Balance: walking on two legs over uneven ground is a hard control problem.
• Cost: many motors and sensors make humanoids expensive to build.
• Power: batteries limit how long a robot can work between charges.
• Hands: matching human dexterity remains one of the toughest challenges.

That's why most humanoids today are in pilots and testing rather than everyday jobs. For robots that already work safely next to people on factory floors, see cobots.