Design and Evaluation of a Teleoperated Surgical Manipulator with an Additional Degree of Freedom for Laparoscopic Surgery

This paper describes a teleoperated surgical manipulator with an additional degree of freedom (d.o.f.). If the surgical manipulator has the same number of d.o.f. as a human arm, intuitive movements of the surgical manipulator will be achieved and the movements of the surgical manipulator will be easily predictable. The proposed surgical manipulator affords 7-d.o.f. joints using a cable–pulley mechanism. The surgical manipulator has upper and lower arms akin to a human arm, and has an elbow joint as an additional d.o.f. joint. In addition, a remote controller was developed to measure the human arm position and deliver the angle data of the 7-d.o.f. joints to the surgical manipulator by TCP/IP communication. The calculated joint angles from the remote controller have a linear relationship with the measured angles from a human arm. The tracking experiment was performed and an approach angle to the surgical site was measured using a liver model. The proposed manipulator has a wider angle range compared to that of a conventional surgical tool. The surgical manipulator can also perform surgical tasks near the bottom of the liver model.