Multimodal Robots, AKA Transformers

The cool thing about biomimetic or bioinspired robots is how we learn to understand both natural evolution and fundamentals of the problems. For example, making a robot that moves like a snake gives us an understanding of how snakes might evolve, and also an appreciation of an interesting way to get around the world.

Humans being humans, designers are not content with only a single inspiration at a time. We want to mash them up. Flying snakes! Swimming birds! You get the picture.

And, as it happens, we can learn even more about evolution and the world from this kind of exploration.

Evan Ackerman comments on two recent papers that explore “multimodal” locomotion, robots that combine more than one way of moving.

One idea from Jacob S. Izraelevitz, and Michael S. Triantafyllou  mashes up aerial and aquatic “flapping”, looking the different naturally evolved strategies and trying to create a robot that can do either style as needed. The design is realized in a complex two part wing that can emulate a bird wing or a turtle flipper.

Image: MIT Comparison of backwards downstroke (A) and forwards downstroke (B). Various animals are able to change the direction of fluid force, denoted in red, by changing the stroke angle β relative to oncoming flow.

I would just comment that this general purpose wing is probably not going to give the highest performance for either environment, especially compared to optimized “specialist” wings. If nothing else, the natural systems imitated are scarcely the highest performers in the natural world themselves. (I mean, turtles swim fine, but: Tuna!)

The second idea from Robert Siddall, Mathieu de Launay, and Mirko Kova,  is a “flying squid” concept, an aerial robot that dives into water (“a controlled crash landing”), collects water, and then flies powered by a water jet. As far as I can tell, this is a one-shot flight. So you might drop the device into the water, collect info, and then zoom up in the air to rapidly return to the base ship. Or something.  (It’s a little unclear what this would actually be used for.)

Again we learn about naturally evolved systems (flying squids), as well as the inherent challenges of jet propelled flight.  For starters, it takes a lot of reaction mass to lift even a tiny weight.  This device  is not likely to carry passengers or even water samples.  Just information, which is real light.

We all know where this is going. Multimodal flapping, with water jet propulsion! Because we can!

(Actually, we really can.)


  1. Izraelevitz, Jacob S. and Michael S. Triantafyllou, A Novel Degree of Freedom in Flapping Wings Shows Promise for a Dual Aerial/Aquatic Vehicle Propulsor. Preprint arXiv:1412.3843 [physics.flu-dyn], 2014.
  2. Siddall, Robert, Mathieu de Launay, and Mirko Kova, Design of a Robotic Jet Thruster for an Aquatic Micro Air Vehicle. Pre print, 2014.


Robot Wednesday

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