Design of a Modular Continuum-Articulated Laparoscopic Robotic Tool With Decoupled Kinematics

Robot-assisted laparoscopic minimally invasive surgery has gained significant attentions due to its enhanced dexterity, improved precision, natural eye-hand coordination, etc. In these procedures, stick-like surgical tools with distal wrists are usually maneuvered by multiple patient-side manipulators to perform an operation. These patient-side manipulators shall realize remote center of motion movements and are subject to risks of mutual collisions during motion. On the other hand, the continuum surgical manipulators, often with multiple segments, usually have several degrees of freedom (DoFs) for the movements in a patient's cavity, and only need a lockable bedside stand, rather than a manipulator. However, the continuum segments inherently have limited bending curvature such that large orientation changes of the surgical end effector around confined anatomical features can be challenging. This letter, hence, proposes a modular continuum-articulated laparoscopic robotic tool design with simple and decoupled kinematics. An inverted dual-continuum mechanism is used in the tool to realize pure translations, while a 2-DoF cable-driven distal wrist is incorporated for orientations. The utilized dual-continuum mechanism maintains a constant length across its entire cross section to significantly facilitate maintaining tensions for the actuation cables of the distal wrist. Design concept, kinematics, system descriptions, actuation calibration, and experimental characterizations are reported, demonstrating effectiveness of the proposed idea.