Kinematics of a new 2-DoF wrist with high angulation capability

This paper presents the synthesis and the analysis of the kinematics of a new robotic parallel wrist for laparoscopic surgery applications. The main properties of this new wrist are the wide singularity free orientation workspace and the capability of making large rotations of the end-effector with small rotation of the actuators. First, it is shown how these features suit the application of minimally invasive surgery. Secondly, the kinematics is described showing its working principle that allows the achievement of rotation multiplication. The forward kinematics problem is solved geometrically. Afterwards, a methodology based on screw theory for the solution of the differential kinematics is proposed. Finally a workspace representation is presented making a comparison with another known parallel wrist