Imagine a group of underwater robots working together to explore the mysterious depths of the ocean and assist in scientific research or rescue missions. In a recent study published in Scientific Reports, researchers from Brown University have made significant progress in creating these types of underwater navigation robots. The study introduces Pleobot, a small robotic platform that mimics the swimming movements of krill. This design not only helps researchers understand krill-like swimming, but also serves as a foundation for building highly maneuverable underwater robots.
The Design of Pleobot
Inspired by the agility and mastery of swimming displayed by krill, Pleobot consists of three articulated sections that replicate the metachronal swimming technique. By studying the fluid-structure interactions needed for steady forward swimming in krill, the researchers demonstrate the capabilities of Pleobot to imitate these swimming movements. This small robotic platform has the potential to unlock valuable insights and allow scientists to engineer more efficient ocean navigation robots.
Understanding Krill-like Swimming
Pleobot provides unparalleled resolution and control for investigating the various aspects of krill-like swimming. Sara Oliveira Santos, a Ph.D. candidate at Brown’s School of Engineering and lead author of the study, explains that the goal was to design a comprehensive tool to understand the athleticism of krill’s swimming techniques. These experiments with Pleobot allow researchers to study the mechanisms of swimming that enable krill to excel underwater.
The Significance of Metachronal Swimming
The study aims to understand how metachronal swimmers, such as krill, navigate complex marine environments and perform vertical migrations. These swimmers can travel over 1,000 meters vertically, equivalent to stacking three Empire State Buildings, twice a day. The researchers built Pleobot to precisely emulate the essential movements of krill’s legs, enabling measurements and comparisons that would be challenging with live animals.
Furthermore, the researchers believe that swarm systems inspired by krill’s metachronal swimming technique could be utilized for ocean mapping, search-and-recovery missions, or exploring oceans on other celestial bodies like Europa.
“Krill aggregations demonstrate remarkable underwater maneuverability and serve as an excellent example of swarms in nature,” says Monica Martinez Wilhelmus, Assistant Professor of Engineering at Brown University. This study lays the foundation for developing the next generation of autonomous underwater sensing vehicles by understanding fluid-structure interactions at the appendage level.
Pleobot’s capabilities include active control of two leg segments and passive control of biramous fins. The researchers proudly highlight that Pleobot is the first robotic platform to replicate the opening and closing motion of these fins. This multi-year project involved a multidisciplinary team in fluid mechanics, biology, and mechatronics.
Unveiling the Mechanisms of Krill Swimming
The researchers built their model of Pleobot at a larger scale than actual krill, which are typically the size of a paperclip. This 3D printable platform was designed to answer various questions about metachronal swimming not only in krill but also in other organisms like lobsters. Through their study, the team discovered how krill generate lift to avoid sinking while swimming forward. By observing Pleobot in action, they identified a low-pressure region at the backside of the swimming legs that contributes to lift force enhancement during the power stroke.
The Future of Pleobot and Research
Building on their initial success, the researchers plan to continue developing and testing the designs presented in the study. Their next objective is to incorporate morphological characteristics of shrimp, such as flexibility and bristles, into the Pleobot platform. This would further enhance its functionality and versatility. The work was partially funded by a NASA Rhode Island EPSCoR Seed Grant.