A Labriform-Inspired Multi-Stable Soft Robotic Swimmer
Jiaqiao Liang, Zefeng Xu, Peiyu Liu, Qiaosong Fan, Linjun Liu, Bin Xie, Ye Chen, Yitong Zhou
Abstract
Pectoral-fin-based (labriform) swimming combines high-speed propulsion with agile maneuverability through rigid-flexible fin partitioning. Inspired by this principle, we present a multi-stable soft robotic swimmer composed of two wedge-shaped bistable actuators integrated with fin-like rigid-flexible morphologies. The bistable actuators generate large, rapid deformations for thrust production, while the compliant fin membranes enable drag-reducing feathering during recovery. An analytical model is developed to predict the shape of bistable actuators and is validated experimentally with a minimum prediction accuracy of 97.74%. Computational fluid dynamics (CFD) analysis reveals that bistable switching induces vortex dipole ejection, contributing to thrust generation. The proposed robot attains a maximum speed of 17.53 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\text{cm.s}^{-1}$</tex-math></inline-formula> (1.10 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\text{BL.s}^{-1}$</tex-math></inline-formula>), a turning radius of 0.58 per body length, and a turning speed of 31.51<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$^\circ$</tex-math></inline-formula>/s, highlighting our design in shaping both swimming speed and maneuverability. By integrating bistable actuation with bio-inspired fin morphologies, this work offers a principled design strategy for achieving fast and maneuverable swimming in robotic systems.
BibTeX
@inproceedings{ral2026_alabriforminspir,
title = {A Labriform-Inspired Multi-Stable Soft Robotic Swimmer},
author = {Jiaqiao Liang and Zefeng Xu and Peiyu Liu and Qiaosong Fan and Linjun Liu and Bin Xie and Ye Chen and Yitong Zhou},
booktitle = {RA-L 2026},
year = {2026}
}