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Main Authors: Chen, Zhiheng, Wang, Wei
Format: Preprint
Published: 2025
Subjects:
Online Access:https://arxiv.org/abs/2509.16145
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author Chen, Zhiheng
Wang, Wei
author_facet Chen, Zhiheng
Wang, Wei
contents Fish-inspired aquatic robots are gaining increasing attention in marine robot communities due to their high swimming speeds and efficient propulsion enabled by flexible bodies that generate undulatory motions. To support the design optimization and control of such systems, accurate, interpretable, and computationally tractable modeling of the underlying swimming dynamics is indispensable. In this letter, we present a full-body dynamics model for motor-actuated robotic fish, rigorously derived from Hamilton's principle. The model captures the continuously distributed elasticity of a deformable fish body undergoing large deformations and incorporates fluid-structure coupling effects, enabling self-propelled motion without prescribing kinematics. Preliminary open-loop simulations examine how actuation frequency and body stiffness influence the swimming speed and energy efficiency of the robotic fish. Closed-loop simulations further assess how stiffness distribution impacts the controller's velocity-tracking performance and energy efficiency. The results demonstrate the model's potential for performance evaluation and control optimization of soft robotic swimmers when stiffness is treated as a design variable.
format Preprint
id arxiv_https___arxiv_org_abs_2509_16145
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Modeling Elastic-Body Dynamics of Robotic Fish Using a Variational Framework
Chen, Zhiheng
Wang, Wei
Robotics
Fish-inspired aquatic robots are gaining increasing attention in marine robot communities due to their high swimming speeds and efficient propulsion enabled by flexible bodies that generate undulatory motions. To support the design optimization and control of such systems, accurate, interpretable, and computationally tractable modeling of the underlying swimming dynamics is indispensable. In this letter, we present a full-body dynamics model for motor-actuated robotic fish, rigorously derived from Hamilton's principle. The model captures the continuously distributed elasticity of a deformable fish body undergoing large deformations and incorporates fluid-structure coupling effects, enabling self-propelled motion without prescribing kinematics. Preliminary open-loop simulations examine how actuation frequency and body stiffness influence the swimming speed and energy efficiency of the robotic fish. Closed-loop simulations further assess how stiffness distribution impacts the controller's velocity-tracking performance and energy efficiency. The results demonstrate the model's potential for performance evaluation and control optimization of soft robotic swimmers when stiffness is treated as a design variable.
title Modeling Elastic-Body Dynamics of Robotic Fish Using a Variational Framework
topic Robotics
url https://arxiv.org/abs/2509.16145