Hardware & control
Locomotion
Robot locomotion is the process by which a robot transports its body from one place to another through physical interaction with its environment. Robots may walk, roll, crawl, hop, fly, or swim. For a humanoid, locomotion usually means coordinated legged movement such as walking, turning, stepping, climbing, or recovering balance.
Also known as: robot locomotion, robotic locomotion
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Locomotion is physical movement, not navigation
Locomotion concerns how a robot generates motion through contact with its environment. Navigation concerns where the robot should go and how it plans a route. A navigation system may choose a destination while a locomotion controller turns that decision into wheel motion, footsteps or another mode of travel.
The MIT Press introduction to mobile robots treats locomotion mechanisms, sensing, localisation and planning as connected but distinct parts of mobility. Wheels are efficient on suitable ground; legs can place contacts across gaps, steps and uneven terrain at the cost of greater mechanical and control complexity.
Humanoid locomotion is a contact-switching problem
Bipedal walking repeatedly makes and breaks foot contact. Impacts, friction limits, centre-of-mass motion, angular momentum, joint limits and actuator capability all affect whether a step remains stable. The MIT notes on legged robots explain why humanoid control often uses simplified centre-of-mass dynamics and footstep planning despite the full body's complexity.
A gait describes a recurring pattern of contacts and body motion, such as walking or running. Locomotion is broader: it includes starting, stopping, turning, climbing, transition between gaits and recovery after a disturbance.
Useful locomotion data extends beyond joint angles
A motion clip can show the visible pose while omitting the forces and state that kept the robot upright. Training records may need joint position and velocity, commanded and measured torque, base pose, IMU data, foot contacts, ground reaction forces, terrain geometry, target velocity and intervention or fall labels.
The robot model, footwear, payload, control rate and support surface are also part of the context. Those fields help distinguish a reusable movement pattern from a trajectory that worked only under one embodiment and floor condition.
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Related terms
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.
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.
Data & collection
Trajectory
A trajectory is a time-ordered sequence of states or observations, actions and, where applicable, rewards generated as an agent or robot evolves. A complete episode or policy rollout often yields a trajectory, but the terms are not universally identical: trajectories may be partial, while episodes have dataset- or environment-defined boundaries.
Hardware & control
Loco-manipulation
Loco-manipulation is the integrated performance of locomotion and object manipulation, in which a robot moves its own body while reaching, carrying, pushing, pulling, or otherwise controlling something in the environment. In humanoids and other legged robots, the task couples contact planning, balance, whole-body motion, and manipulation rather than treating walking and arm control as independent stages.