Single-port multichannel multi-degree-of-freedom robot with variable stiffness for natural orifice transluminal endoscopic surgery

Abstract Natural orifice transluminal endoscopic surgery (NOTES) emerges with advantages of less scar, less pain or bleeding, and better anesthesia, in comparison with open or laparoscopic surgery. Current surgical instruments for NOTES lack stiffness tuning capability and require high-level surgical skills, as the natural orifice is long and narrow. The conventional robots with constant stiffness are not ideal for NOTES, because variable stiffness of the manipulator is desirable for satisfactory dexterous operation and navigating through transluminal trajectories. Flexibility is essential for safe curvilinear access, while rigidity is essential for dexterity. As a result, we are addressing the stiffness modulation needs by developing a robotic endoscopy system with variable stiffness and flexible manipulators for NOTES. A single-port multichannel multi-degree-of-freedom robot with variable stiffness in this work is composed of a camera and two manipulators based on the endoscopic platform. The manipulators are compliant with variable stiffness, and the wrist joints are flexible. The stiffness of the compliant manipulator tunes in real-time during the operation to fulfill the accuracy and safety requirements of the surgery environment. The mechanism and experiments validate the variation of the stiffness. Results show that the stiffness of the manipulator is variable, which can be tuned by the tension of the wires.