Colonial Architectures for Centimeter-Scale Underwater Robot Swarms
Pascal Spino, Marc Bäckert, Lianhao Yin, Daniela Rus
AI summary
Problem
Micro underwater robots are limited by severe communication constraints, onboard power limits, and low propulsion efficiency, which restrict their operational range and capability. This paper addresses the gap of identifying swarm morphologies that scale performance with the number of robots in underwater environments.
Approach
The authors developed a modular, centimeter-scale underwater robot with magnetic docking interfaces and onboard sensing, then experimentally tested how physically connecting these units into chain aggregates affects collective propulsion, efficiency, and task performance.
Key results
- Autonomous self-assembly and disassembly using only onboard vision and magnetic docking
- Chain aggregates achieve up to 80% higher swimming speeds and over 86% lower cost of transport than individuals
- Rear-only thrust strategy yields highly efficient collective locomotion with gradual speed reduction as chains lengthen
- Connected groups achieve superior station-keeping accuracy without inter-robot communication
Why it matters
This bioinspired modular architecture overcomes fundamental limitations of micro underwater robots, enabling more capable, efficient, and scalable aquatic exploration and monitoring.
Abstract
Micro underwater robots offer scalable and low- cost access to environments that are difficult to study with conventional vehicles, but severe communication constraints, limited onboard power, and low swimming speed restrict the capability of these miniature systems. Inspired by colonial organisms such as salps and siphonophores, this work explores physically connected swarms of small underwater robots that form larger structures with improved collective performance. We present a modular platform of centimeter-scale robots capable of three-dimensional propulsion, onboard sensing, and autonomous behavior, with magnetic interfaces that enable reversible connections into prescribed morphologies. Exper- iments demonstrate autonomous assembly and disassembly, quantify the propulsive benefits of chain aggregates, and show that mechanically coupled robots can distribute sensing, actu- ation, and control across the collective. Results indicate that certain colonial architectures can greatly improve swimming speed, locomotion efficiency, and task performance compared to individual robots, suggesting a path toward more capable centimeter-scale underwater swarms.