Definition
Joint space (also called configuration space or C-space) represents the robot's state as a vector of joint angles (θ₁, θ₂, ..., θₙ). For a 7-DOF arm, joint space is 7-dimensional. Motion planning algorithms typically operate in joint space because collision checking and trajectory smoothness are well-defined there. Joint space interpolation produces predictable, smooth motions but may result in non-intuitive Cartesian paths. Conversely, Cartesian (task space) planning is intuitive for human operators but requires solving inverse kinematics at each step. Most practical systems combine both: plan in Cartesian for the end-effector, resolve IK, then smooth in joint space.
Why It Matters for Robot Teams
Understanding joint space is essential for teams building real-world robot systems. Whether you are collecting demonstration data, training policies in simulation, or deploying in production, this concept directly affects your workflow and system design.