A Soft Robot Attachment with Variable Stiffness Effector for Advanced Endoscopic Surgical Tasks

Abstract

This paper presents a soft Cable-Driven Parallel Robot for gastrointestinal surgery. The robot consists of an inflatable scaffold and a hydraulic variable stiffness end-effector and features six degrees of freedom. Experiments involving passage through a colon model, knot tying, and retraction have demonstrated its flexibility and the concept of navigating through the colon in a soft configuration, then increasing rigidity at the lesion site to collaborate with the endoscope in performing surgery. Meanwhile, the robot can sense the contact force through hydraulic pressure variations within the end-effector shaft, providing haptic feedback, which reduces the effects of Coulomb friction. When using the robot to calculate pressing forces, it achieved accuracy with a mean error of 0.051 N and a standard deviation (STD) of 0.066 N. For lifting forces, it achieved a mean error of 0.066 N and a STD of 0.083 N. These results demonstrate the potential of the robot for tissue palpation applications.