Pleobot: a modular robotic solution for metachronal swimming

Metachronal propulsion is widespread in aquatic swarming organisms to achieve performance and maneuverability at intermediate Reynolds numbers. Studying only live organisms limits our understanding of the mechanisms driving these abilities. Thus, we present the design, manufacture, and validation of the Pleobot-a unique krill-inspired robotic swimming appendage constituting the first platform to study metachronal propulsion comprehensively. We combine a multi-link 3D printed mechanism with active and passive actuation of the joints to generate natural kinematics. Using force and fluid flow measurements in parallel with biological data, we show the link between the flow around the appendage and thrust. Further, we provide the first account of a leading-edge suction effect contributing to lift during the power stroke. The repeatability and modularity of the Pleobot enable the independent manipulation of particular motions and traits to test hypotheses central to understanding the relationship between form and function. Lastly, we outline future directions for the Pleobot, including adapting morphological features. We foresee a broad appeal to a wide array of scientific disciplines, from fundamental studies in ecology, biology, and engineering, to developing new bio-inspired platforms for studying oceans across the solar system.

Automated summary

Metachronal propulsion is a common method used by aquatic swarming organisms to achieve performance and maneuverability. This study presents the design and validation of Pleobot, a krill-inspired robotic swimming appendage, which is the first platform to comprehensively study metachronal propulsion. By combining a multi-link 3D printed mechanism with active and passive actuation, natural kinematics are generated. The study shows the link between the flow around the appendage and thrust, as well as the contribution of a leading-edge suction effect to lift. The Pleobot's repeatability and modularity allow for independent manipulation of specific motions and traits for testing hypotheses. The study has implications for various scientific disciplines and the development of bio-inspired platforms for studying oceans.