Robot Kinematics

What it is

Kinematics describes the geometric relationship between a robot's joint configuration and the position/orientation of its end effector (its hand, tool, or point of interest) — the math connecting "what the motors are doing" to "where the robot's arm actually is in space."

Key points

• Forward kinematics: given joint angles, compute the end effector's position — a direct, deterministic calculation.
• Inverse kinematics: given a desired end effector position, compute the joint angles needed to reach it — significantly harder, often has multiple valid solutions (or none, if the position is unreachable).
• Degrees of freedom: how many independent ways a robot can move — more degrees of freedom means more flexibility in reachable positions, but also a larger, more complex space of possible joint configurations to search for inverse kinematics.
• Kinematics is purely geometric — it doesn't account for forces, mass, or momentum, which is what dynamics (a related but distinct topic) handles.