Modular tendon routing for continuum manipulators

Tendon-driven continuum manipulators (TDCMs) exhibit inherent compliance akin to biological structures such as an elephant trunk or a octopus tentacle. Despite these advantages, TDCMs commonly struggle in providing the necessary strength to lift heavy loads, and reach a large number of end-effector positions in multiple different orientations. New workspace and deformation profiles can be achieved through alternative tendon-routing configurations: parallel, helical, hybrid. However, such configurations require predefined routing prior to deployment and are strictly limited to their defined metrics. In this thesis, two novel TDCMs are presented featuring subsequent modular disks capable of rotation and locking prior to (a priori) or following manipulator deformations (automated reconfigurable). Rotating one, two or multiple disk angles leads to various non-continuous segmented deformation of the backbone, leading to regions of unique curvatures. Analysis of the curvature is done through both multiple camera reconstruction of the backbone, or through manually recording each position of the disk. A nth-dimensional polynomial is fit through these points and Frenet-Serret theorem is utilized to extract bending, $\kappa$ and torsion, $\tau$ values for a dataset of values rotated to a maximum of $\pm{}90\si{\degree}$. This provides the insight of which modular disks provides the biggest change to curvature. Multiple applications on the a priori manipulator are shown, in which the manipulator achieves common routing paradigms, obstacle avoidance, and taking multiple pictures from different 3D quadrants. The automated reconfigurable manipulator showcases other possibilities such as alternating between specific configurations while held at a fixed tendon displacement. Through the increase of the actuation space through localized modular disk, a larger amount of unique curvatures can be achieved thus improving metrics.

Name thesis:degree_name

M.S.

Level thesis:degree_level

Thesis

Discipline thesis:degree_discipline

Mechanical Engineering

Grantor

University of Illinois Urbana-Champaign

Year dc:date

2025

Author dc:creator

• Golden, John

Contributors dc:contributor

• Krishnan, Girish

• Continuum
• Tendon
• Workspace
• Tendon-driven
• Manipulator
• Modular

Statement dc:rights

• © 2025 John Golden

Language dc:language

en, eng

Handle dc:identifier

https://hdl.handle.net/2142/130217

OAI record oai:identifier

https://www.ideals.illinois.edu/oai-pmh?verb=GetRecord&metadataPrefix=etdms&identifier=oai%3Awww.ideals.illinois.edu%3A2142%2F130217