“…The first category of neck is a rigid structure with 2, 3 or 4 joints, each with 1 DOF. Some examples of those configurations on humanoids robots are: with 2 DOF (Yaw and Pitch movement of the head), ASIMO humanoid [3], HUBO [4], HRP-4 [5], NAO [6], TORO [7], Pepper [8], Marko [9], Woody [10], a humanoid with a wheeled mobile base [11]; with 3 DOF (movements on the yaw, roll and pitch axes), Albert HUBO [12], HRP-4C [13], iCub [14]; with 4 DOF (movements of yaw, roll and upper and lower pitch), ROMAN [15], SAYA [16],…”