A Radial Folding Mechanism to Enable Surgical Continuum Manipulators to Fit Through Smaller Ports

Tendon driven continuum robots promise tentacle-like dexterity in minimally invasive surgical applications. These robots are subject to conflicting design goals. It is desirable for the robot to fit through the smallest port possible, yet it is also desirable for the robot's diameter to be large, so that for a given tension, tendons can apply larger actuation moments to the robot. To satisfy both goals simultaneously, we propose a new radial folding mechanism that facilitates a 2.5x diameter change along the robot. We show that our folding tendon manipulator can be modeled by existing mechanics-based models. Comparing at consistent tendon tensions, the robot has a larger range of motion and larger stiffness than a non-folding continuum robot that fits through the same sized entry port.