What is a humanoid robot?

What makes a robot a humanoid

A humanoid robot is a robot that resembles the human body in shape. It may be designed to use human tools and spaces, to work alongside people, or to study how two-legged walking works.^[5]

Most humanoids have a torso, a head, two arms and two legs. Some have only some of these parts.^[5]

A common variation is an upper body mounted on a wheeled base. Rolling instead of walking greatly reduces the risk of falling that two-legged robots face.^[5]

Whether a humanoid counts as a robot is decided by the same test as any other machine, explained on the page about what a robot is. The human shape is a design choice.

Why build a robot in human shape?

The International Federation of Robotics says humanoids are built to tackle tasks in human-centric environments. The vision is a general-purpose robot that can do many tasks, not just one.^[6]

Its argument is about our surroundings: to the extent that our environments are optimized for the human body, a robot based on human form could have an advantage. It also points to labour shortages and ageing populations in most developed economies.^[6]

Makers say the same thing in their marketing. Agility Robotics says Digit's human form factor means industrial environments don't have to be redesigned, and Boston Dynamics tells customers to "stop restructuring your workspace for your robots".^{[1] [2]}

Not everyone is convinced the human shape is worth it. Honda, which built the humanoid ASIMO, now pursues several robots, each built for a specific purpose, instead of one humanoid that does everything.^[3]

What is inside a humanoid

Humanoids use proprioceptive sensorsA part that measures something about the world or the robot itself, such as light, distance, or joint angle. to track the position, orientation and speed of their body and joints. They use cameras to recognize objects and microphones to hear speech and other sounds.^[5]

Their joints are driven by actuators, which can be electric, pneumatic or hydraulic. Electric actuators are the most popular.^[5]

To make this concrete, here is how one maker describes one current model. Specifications change between versions, so the entry is dated.

A short history

Waseda University in Tokyo says its WABOT-1, built between 1970 and 1973, was the first full-scale anthropomorphic robot. It could hold a conversation in Japanese, judge distances and directions using artificial eyes and ears, walk, and grip and carry objects with touch-sensing hands.^[7]

Honda developed ASIMO as a humanoid robot meant to help people. Honda says it replicated some human functions through engineering, and that its work included how to keep people safe when ASIMO falls.^[3]

Honda also drew a lesson from it. It says a fully autonomous two-legged robot that can work safely around people still needs long-term research, social consensus and new laws. It now pursues several robots, each built for a specific purpose, instead of one humanoid that does everything.^[3]

Humanoids today

The IFR says generative AIComputer systems that do tasks which usually need human judgment, such as recognizing pictures or writing text. has changed how humanoids acquire skills: they can learn from demonstration and even figure out some tasks on their own.^[6]

Money is pouring in. The IFR says major tech companies such as NVIDIA, Tesla and Amazon have announced significant funding for humanoids, and that China has published detailed goals to mass-produce them.^[6]

Makers now pitch humanoids for factories and warehouses. Boston Dynamics, for example, says Atlas autonomously navigates to a charging station and swaps out its own battery. Claims like this come from the maker, not from independent testing.^[2]

Vision and reality

The IFR titled its position paper on humanoids "Vision and Reality". It says videos on social media of AI-powered humanoids have boosted public interest by suggesting an impending revolution in robotics.^[6]

A short video can show a single successful attempt, a sped-up clip, or a robot guided by a person off camera. The pages on teleoperationA person controlling a robot remotely instead of the robot acting on its own. and on the demo-versus-reality gap explain what to look for.