# Development of a Cuttlefish-Inspired Amphibious Robot with Wave-Motion Propulsion and Rigid–Flexible Coupling

## TL;DR

This paper describes a new amphibious robot inspired by cuttlefish movements that can efficiently move on land and in water.

## Contribution

The novel rigid–flexible coupling mechanism with wave-motion propulsion for amphibious locomotion is introduced.

## Key findings

- The robot successfully demonstrated efficient movement in both terrestrial and aquatic environments.
- Kinematic modeling and simulations validated the wave-like motion and coordination of the propulsion system.
- Experimental testing confirmed the feasibility of the bio-inspired design for amphibious robots.

## Abstract

Amphibious robots require efficient locomotion strategies to enable smooth transitions between terrestrial and aquatic environments. Drawing inspiration from the undulatory movements of aquatic organisms such as cuttlefish and knifefish, this study introduces a bio-inspired propulsion system that emulates natural wave-based locomotion to improve adaptability and propulsion efficiency. A novel mechanism combining crank–rocker and sliding components is proposed to generate wave-like motions in robotic legs and fins, supporting both land crawling and aquatic paddling. By adopting a rigid–flexible coupling design, the system achieves a balance between structural integrity and motion flexibility. The effectiveness of the mechanism is systematically investigated through kinematic modeling, animation-based simulation, and experimental validation. The developed kinematic model captures the principles of wave propagation via the Crank–Slider–Rocker structure, offering insights into motion efficiency and thrust generation. Animation simulations are employed to visually validate the locomotion patterns and assess coordination across the mechanism. A functional prototype is fabricated and tested in both terrestrial and aquatic settings, demonstrating successful amphibious locomotion. The findings confirm the feasibility of the proposed design and underscore its potential in biomimetic robotics and amphibious exploration.