Conceptual design and dimensional synthesis of “MicroHand”

A master–slave surgical robotic system can make the best use of both a doctor’s experience and the characteristics of precise positioning, stable performance and dexterous manipulability of a robot. A new surgical robotic system “MicroHand” is presented in this paper with a master–slave isomerous mechanism to provide more design freedoms. The master of “MicroHand” is a Phantom Desktop device and the slave manipulator is a system designed using a position mechanism and an orientation mechanism. The position mechanism implements the kinematic characteristics of a double parallelogram mechanism driven by a cable, which can decouple the position and posture of the slave manipulator. The orientation mechanism applies three rotating axes intersecting at one point to ensure that the surgical tools have enough dexterity at any position in the workspace. The position mechanism and its parameters are designed based on kinematic analysis of two cable-driven linkage structures and kinematic conditioning index. The suitable positions are analyzed in the workspace of a single arm and also in the coworkspace of the two arms. The optimal results show that the “MicroHand” system can enhance the ability of the surgeon in a blood vessel (1 mm in diameter) suturing and knotting experiment.