Robotics
Configuration space
Definition
Configuration space is the set of all possible configurations of a robot or mechanical system. Each point specifies the entire modeled arrangement, and the space has as many local dimensions as the system has degrees of freedom.
Also known as: C-space, Configuration space of a robot
Updated
A point can describe a whole robot
For a two-joint arm, one configuration can be recorded as two joint angles. A path through configuration space then describes how both angles change together. It is not the path traced by the hand alone: different whole-arm configurations can place the hand at the same point.
Modern Robotics defines the configuration by the positions of all points on the modeled robot, compressed into independent coordinates where possible.
Angles make the space wrap around
The space need not behave like an ordinary flat coordinate grid. Two freely rotating joints have a configuration space shaped like a torus. Each angular coordinate wraps around after one revolution.
The configuration-space topology lesson shows why a smooth physical motion can cross a discontinuity in its numerical angle representation. Joint limits change the permitted set, so unrestricted circular coordinates should not be assumed for every joint.
Configuration space and workspace differ
Workspace describes reachable end-effector poses or positions. Configuration space describes the robot's complete arrangement, as the task-space comparison explains. Forward kinematics maps from the latter to the former, which is why several configuration-space points can correspond to one task-space target.
Sources
Related terms
Degrees of freedom
Degrees of freedom are the number of independent coordinates needed locally to describe a system configuration. In robotics, this count depends on the bodies, joints, and independent constraints in the model.
Workspace
A robot workspace is the set of positions or poses its end-effector can reach under specified geometric and joint constraints. Its meaning depends on whether orientation is included and which base and tool configuration are assumed.
Motion planning
Motion planning finds a robot movement from an initial state to a goal while satisfying constraints such as collision avoidance. A planner may produce a geometric path, a timed trajectory, or a sequence of controls.