Convergent Science Network » Robojelly

Wings and fins bend…in the same way

Dmitry Malkov — Tue, 04 Mar 2014 08:26:17 +0000

What do a bat, a jellyfish and a humpback whale have in common? For one thing, these animals use their natural propulsors, such as wings, bells and flukes, to move through their environment, be it air or water. Last week a group of researchers published a study in Nature Communications that indicates that these and many other animals from distantly related groups seem to have attended the same school of propulsion. And one of the subjects they studied there was all about being flexible.

By analysing videos of 59 animals in steady motion, the researchers have discovered that most animal propulsive structures are surprisingly finely tuned as they bend at the tip in a way that shows very little variation across taxonomic groups, fluid medium and size – with the bending angle ranging from about 15° to 40°. No matter whether it is an insect, a bird, a fish, a mollusk or a cetacean, these newly discovered bending rules of propulsion apply to practically all of them.

The study suggests that this unique kinematic property of natural propulsors was independently reinvented again and again through evolutionary processes in entirely different groups of animals – a phenomenon that the authors of the study attribute to the advantages that bending propulsors imply for energy efficient thrust production.

The results of the study may open new possibilities in the design of biologically inspired propulsion systems, such as Robojelly, a Navy-funded robot jellyfish we featured in one of our previous posts, or its big brother Cyro, both of which have already confirmed the importance of flexible propulsors in underwater vehicles.

Robojelly

Michelle Wilson — Thu, 12 Apr 2012 07:20:00 +0000

This robot’s not snacking on shrimp or plankton to get its energy

Many of us consider jellyfish a nuisance when we’re walking along the beach or swimming in salty waves. While some species are highly hazardous, and others are nothing but harmless, for a bunch of (essentially) brainless animals, they sure do have some moves!

Researchers at The University of Texas at Dallas and Virginia Tech have created an underwater robot inspired by the moon jellyfish. The robot’s structure includes a double layered bell-shaped silicon umbrella attached to artificial muscles that contract when heated. These mock-muscles put this bot ahead of the game! As the water’s hydrogen and oxygen contacts the pseudo-jelly’s platinum coated carbon nanotubes, heat and water vapor are naturally created. The heat causes a contraction that moves the muscles of the machine while pumping out the water and initiating the cycle again.

Since this bot feeds off water’s natural elements, it’s never in need of any refueling. Likewise, water is all it releases back into the environment so it gets itself around in an environmentally friendly fashion!

Research for the development of Robojelly was funded by the USA’s Office of Naval Research which is particularly interested in the robot’s ability to monitor the seas however, researchers suggest it could also be used to measure levels of pollutants in large bodies of water.

The combination of new materials and creative engineering are paving the way for all sorts of green energy solutions. Click HERE to check out a European initiative which believes in the importance of creating helpful machines in a sustainable way.