Introducing Forward and Inverse Kinematics

Forward and inverse kinematics generally relate to a system of connected parts, such as a chain or a jointed arm. They have to do with how that system moves, and how each part moves in relation to the other parts and to the whole.

Often, a kinematics system has two ends: the base and the free end. A jointed arm is usually attached to something fixed at one end, and the other end moves around to reach and grab things. A chain might be attached to something on one or both ends, or not at all.

Forward kinematics(FK) deals with motion that originates at the base of the system and moves out to the free end. Inverse kinematics(IK) deals with the opposite: motion originating at, or determined by, the free end and going back to the base, if there is one.