Doctor of Philosophy (PhD)
Mechanical and Industrial Engineering
Continuum robots offer many advantages for use in miniature diagnostic and interventional surgical devices. However, the creation of snake-like devices with extremely high slenderness ratios, those with great length and small diameter, remains challenging from a device design perspective. To facilitate improved slenderness ratios, high total accumulated bending angles, and high stiffness and mechanical stability of the active section, we propose the use of a long flexible screw-driven mechanism to generate distal motion while still locating motors and other bulky system components at the base of the device. In comparison to tendon-based designs and push-pull rods, the design avoids the capstan-like buildup of friction. In this work, we present design, fabrication, kinestatic modeling, and experimental validation for a three-degree-of freedom, screw-based, multi-backbone continuum robot with soft exterior. The model that compensates the friction in the system most accurately predicts the behavior of the robot and eliminates most of the hysteresis in the input-output behavior. A screw-driven actuator with long passive section is also investigated. Closed-loop control demonstration shows tracking error in sub-mm region for the long robot. To effectively support the screw-driven end-effector a tendon-driven bracing mechanism is also described. A design, proof-of-concept and characterization of a physically intelligent soft robot that can be integrated with the long continuum robot is also presented here. The proposed soft robot may ensure soft contact at each contact of the continuum robot with the tissue of the inner wall of highly tortuous lumen.
Ahmed, Shahrior, "A Long Screw-Driven Continuum Robot with Soft Exterior" (2023). LSU Doctoral Dissertations. 6046.
Gilbert, Hunter B.
Available for download on Monday, January 28, 2030