6-DoF Surgical Robot Arm Capable of Accessing Behind Organs

Abstract

This paper presents the redesign and validation of a modular 6-DOF robotic surgical instrument for Robot-Assisted Minimally Invasive Surgery (RMIS) through sub-2 cm incisions. To address torsional compliance, backlash, and unreliable distal actuation from fully flexible shafts, a rigid–flexible–rigid transmission is introduced, localizing compliance to the elbow while increasing overall torsional stiffness. Modeling and FEA show reduced angular twist and improved torque transmission. A redesigned cable-driven system, modular docking interface, and internal cable management enhance decoupling, durability, and assembly. Testing confirms independent 6-DOF control, 360° shoulder and wrist rotation, and improved grip reliability without spring-like distal motion