Characterization of a Screw-Based Bending Actuator for Continuum Robots

Abstract

Long, thin continuum robots may be useful in a wide variety of inspection and maintenance tasks and medical applications as robotic endoscopes and minimally invasive surgical devices. To facilitate improved aspect ratios, high total accumulated bending angles, and high stiffness and mechanical stability of the active section, we propose the use of a flexible screw-driven mechanism to facilitate the combination of proximally mounted actuators and distal bending sections. In comparison to tendon-based designs and push-pull rods, the design avoids the capstan-like buildup of friction. In this work, we model and experimentally characterize a single degree-of-freedom, screw-based, multi-backbone bending actuator for continuum robots. In comparison to a tendon-based actuator, the prototype is stiffer in the active bending direction by a factor of 2.75. The maximum bending angle at failure is also measured by hand actuation and the factors that contribute to performance limits and model inaccuracy are discussed.