2025 IEEE International Conference on Robotics and Automation (ICRA)

The phenomenon of the “traveling wave,” com- monly observed in various organisms, involves a wave that propagates along the body, serving as a locomotion mechanism. Particularly, in aquatic environments, organisms such as fish and cetaceans utilize traveling waves to propel themselves through water, minimizing fluid drag and maximizing move- ment efficiency. Inspired by nature, robotics has extensively explored replicating such locomotion strategies. This work presents a fish robot with an innovative magnetic transmission system. The mechanism transforms the unidirectional rotation of a single motor into an oscillatory, phase-shifted movement across the modules of the kinematic chain, generating a travel- ing wave along the body. The robot’s design and functionality are detailed, highlighting advancements in bio-inspired robotics for underwater applications, such as efficient and non-invasive monitoring and exploration of marine ecosystems. The fish robot achieved a swimming speed of approximately 2 body lengths per second (BL/s) with a tail-beat frequency of 3.24 Hz and a minimum Cost of Transport (CoT) of 5.33 J/(kg·m). Biomimetic robotics can play a key role in sustainable aqua- farming, biodiversity conservation, and animal-robot interac- tion research, offering the potential to minimize ecosystem disruption and advance marine science.