This is the API reference of the Kinematics and Dynamics Library (KDL), a sub-project of Orocos, but that can be used independently of Orocos. KDL offers different kinds of functionality, grouped in the following Modules:

Geometric Primitives
Kinematic Families : functionality to build kinematic chains and access their kinematic and dynamic properties, such as e.g. Forward and Inverse kinematics and dynamics.
Motion : functionality to specify motion trajectories of frames and kinematic chains, such as e.g. Trapezoidal Velocity profiles.
KDLTK : the interface code to integrate KDL into the Orocos Real-Time Toolkit (RTT).