Closed-Loop Cooperative Manipulation of Deformable Tissue via Visual Feedback Using Multiple Continuum Surgical Manipulators

Continuum surgical manipulators exhibit promising potential in single-port laparoscopy due to their dexterity and design compactness. However, it is challenging for one continuum surgical manipulator to handle heavy tissues during a procedure. This letter hence proposes a closed-loop pose control framework that allows cooperative manipulation of deformable tissues using multiple continuum manipulators, leveraging the inherent visual feedback of a surgical robotic system. In the proposed control framework, the continuum manipulators and the deformable tissues that are gripped by the manipulators are firstly treated as a parallel continuum kinematic chain. The deformable tissues are simplified as elastic tissue rods to facilitate the derivation of a kinetostatics model for the parallel continuum kinematic chain based on the Cosserat rod theory. A stiffness and external wrench estimator and an inverse kinetostatics solver are then developed and utilized alternatively and iteratively in each control cycle. The effectiveness of the proposed control framework is verified through multiple experimental studies on a single-port endoscopic surgical system.