Hardware & control
Humanoid robot
A humanoid robot is a robot whose body is modelled on the human form, typically with a torso, head and limbs, so it can move through human spaces or use human-scale tools and interfaces. The term describes morphology, not intelligence or autonomy; wheeled, partial-body and simplified-hand designs are also sometimes classed as humanoids, so the robot's actual configuration should be stated.
Also known as: humanoid, humanoid robots
Updated
The form defines the category
ISO 8373:2021 describes a humanoid robot through its human-like body, head, limbs and movement. A common full-body design has a torso, head, two arms and two legs, but the useful boundary is functional as well as anatomical: the body is intended to interact with environments, tools and interfaces built around people.
The label does not establish how capable the robot is. A humanoid may be autonomous, supervised, teleoperated or moved through a fixed demonstration. It may use a learned policy or conventional control. Intelligence, reliability and task range must therefore be evaluated separately from body shape.
Why use a human-like body?
Human infrastructure assumes human reach and mobility. Shelves, stairs, doors, workbenches, vehicles, hand tools and controls are positioned for our bodies. A compatible robot may automate part of an existing site without rebuilding every station around a fixed arm or conveyor.
That advantage is conditional. The International Federation of Robotics notes that humanoids do not match established industrial robots for speed, precision, reliability or repeatability. The human form adds joints, balance constraints, energy use and fall risk. A humanoid is most useful when access to human infrastructure or movement between several tasks offsets that complexity.
The boundary is broader than two arms and two legs
The archetypal humanoid is bipedal, but industry usage is less strict. Some platforms retain a human-scale torso and two arms while using wheels for efficient movement on flat floors. Others omit a face, use two-finger grippers instead of hands or provide only an upper body. Apptronik, for example, offers Apollo 2 with bipedal and wheeled mobility.
For technical comparison, “humanoid” is not enough detail. A specification should state the mobility system, limb configuration, hands or other end effectors, degrees of freedom, payload, sensors and control mode. The article on applications of humanoid robots shows why those differences matter in factories, homes, hospitals and hazardous environments.
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Related terms
Hardware & control
Actuator
An actuator is a robot’s power mechanism that converts electrical, hydraulic, pneumatic or other supplied energy into controlled mechanical force, torque or motion. In a humanoid, actuators drive joints, often through transmissions; they are distinct from the joints and sensors, and their arrangement need not correspond one-to-one with the robot’s degrees of freedom.
Hardware & control
Degree of freedom
A degree of freedom (DoF) is one independent parameter needed to specify a robot’s configuration; equivalently, a robot’s DoF is the dimension of its configuration space. It describes possible motion, not the number of motors. Joint constraints, closed kinematic chains and environmental contacts can make joint count, actuator count and controllable motion differ.
Hardware & control
Whole-body control
Whole-body control coordinates a humanoid’s full multibody state, actuated joints and environmental contacts to pursue several motion or force objectives while respecting constraints such as balance, joint limits and friction. It is a family of hierarchical or optimisation-based methods, not one algorithm; implementations may output joint positions, accelerations or torques.
Hardware & control
Proprioception
Proprioception is sensing of a robot’s own internal configuration and motion rather than the external scene. For a humanoid it commonly includes joint positions and velocities, actuator effort or torque, and inertial measurements of body rotation and acceleration. These signals support state estimation and feedback control but do not, by themselves, directly describe nearby objects or terrain.
Hardware & control
End effector
An end effector is a task-specific device attached to a robot manipulator’s mechanical interface so the robot can act on its environment, such as a gripper, hand or welding tool. It is distinct from the wrist or mounting flange, and from the tool centre point, which is only a coordinate frame used to plan the device’s motion.