Definition
Inverse kinematics (IK) solves the mapping from a desired end-effector pose (position + orientation in 3D space) back to the joint angles that achieve it. For redundant robots (more joints than the 6 DOF needed for full pose specification, like 7-DOF or 8-DOF arms), infinitely many solutions exist, and secondary objectives (joint limit avoidance, singularity avoidance, manipulability maximization) select among them. Analytical IK is fast but only available for specific kinematic structures. Numerical IK (Jacobian-based, optimization-based) is general but iterative. Libraries like IKFast, TRAC-IK, and Drake provide robust IK solvers.
Why It Matters for Robot Teams
Understanding inverse kinematics 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.