KDL wiki
Skeleton of a serial robot arm with six revolute joints. This is one example of a kinematic structure, reducing the motion modelling and specification to a geometric problem of relative motion of reference frames. The Kinematics and Dynamics Library (KDL) develops an application independent framework for modelling and computation of kinematic chains, such as robots, biomechanical human models, computer-animated figures, machine tools, etc. It provides class libraries for geometrical objects (point, frame, line,... ), kinematic chains of various families (serial, humanoid, parallel, mobile,... ), and their motion specification and interpolation.