Robot Operating System Cookbook

DoFs for manipulation

DoFs is the word used to refer to the Degrees of Freedom of a robot. And what does this mean? Well, it basically means the number of ways in which a robotic arm can move. A system has n DoFs if exactly n parameters are required to completely specify the configuration:

• In the case of a manipulator robot, the configuration is determined by the number of joints that the robot has. So, the number of joints determines the number of DoFs of the manipulator.
• A rigid object in a 3D space has six parameters, where there are three for positioning (x, y, z) and three for the orientation (roll, pitch, and yaw angles).

If a manipulator has fewer than six DoFs, the arm cannot reach every point in the workspace with arbitrary orientation, ...