Design of Trimmed Helicoid Soft-Rigid Hybrid Robots

TL;DR

This paper introduces a novel soft-rigid hybrid robot design using trimmed helicoid structures, along with a new mechanical model, manufacturing method, and closed-loop demonstrations to advance soft robot capabilities.

Contribution

It combines soft-rigid hybrid design with architectured geometries, provides a mechanical stiffness model, and offers a new manufacturing process with practical demonstrations.

Findings

Successful fabrication of the hybrid robot using injection molding.

Validated the mechanical model with experimental data.

Demonstrated closed-loop control of the robot in practice.

Abstract

As soft robot design matures, researchers have converged to sophisticated design paradigms to enable the development of more suitable platforms. Two such paradigms are soft-rigid hybrid robots, which utilize rigid structural materials in some aspect of the robot's design, and architectured materials, which deform based on geometric parameters as opposed to purely material ones. In this work, we combine the two design approaches, utilizing trimmed helicoid structures in series with rigid linkages. Additionally, we extend the literature on wave spring-inspired soft structures by deriving a mechanical model of the stiffness for arbitrary geometries. We present a novel manufacturing method for such structures utilizing an injection molding approach and we make available the design tool to generate 3D printed molds for arbitrary designs of this class. Finally, we produce a robot using the above methods and operate it in closed-loop demonstrations.