Soft 3D-Printed Endoskeleton for Precise Tendon Routing in Soft Robotics
Emanuele Solfiti, Alessio Mondini, Emanuela Del Dottore, Barbara Mazzolai, Alberto Parmiggiani
Abstract
This paper presents the design, development, and testing of a soft 3D-printed endoskeleton for arbitrary cable routing in tendon-driven soft actuators. The endoskeleton is embedded in a silicone body, and it is fixed to the mold prior to the casting process. It enables tendons to be placed through predefined eyelets, ensuring accurate positioning within the soft body. To minimize its impact on the overall stiffness of the soft body, the endoskeleton was designed with a slim profile, flexible connections, and 3D-printed with elastic material (Shore A hardness 50), selected to roughly match the mechanical properties of the surrounding silicone matrix (typically with Shore 00 hardness 20–30). Key features of the proposed solution include a 3D-printable guide for tendon routing that is (1) fully soft, (2) easy to place, (3) rapidly reconfigurable for arbitrary tendon paths, (4) adaptable to variable soft body geometries, and (5) easy to fabricate with single-step casting. The current work describes the design, manufacturing, simulation, and testing of a simplified case study in which the endoskeleton is employed to reproduce a target pose predicted by FE analysis with good matching, demonstrating the effectiveness of the approach.
BibTeX
@inproceedings{ral2026_soft3dprintedend,
title = {Soft 3D-Printed Endoskeleton for Precise Tendon Routing in Soft Robotics},
author = {Emanuele Solfiti and Alessio Mondini and Emanuela Del Dottore and Barbara Mazzolai and Alberto Parmiggiani},
booktitle = {RA-L 2026},
year = {2026}
}