Modular tendon routing for continuum manipulators

Golden, John

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

Description

Title

Modular tendon routing for continuum manipulators

Author(s)

Golden, John

Issue Date

2025-07-22

Director of Research (if dissertation) or Advisor (if thesis)

Krishnan, Girish

Department of Study

Mechanical Sci & Engineering

Discipline

Mechanical Engineering

Degree Granting Institution

University of Illinois Urbana-Champaign

Degree Name

M.S.

Degree Level

Thesis

Keyword(s)

• continuum
• tendon
• workspace
• tendon-driven
• manipulator
• modular

Abstract

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.

Graduation Semester

2025-08

Type of Resource

Thesis

Handle URL

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

Copyright and License Information

© 2025 John Golden

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