looking towards robotic undulatory locomotion

August 23, 2009

Have you ever been walking in the woods and come upon a snake (startling both you and it), only to see it slither away with incredible speed? I know I have. How is it possible for the massive bulk of a whale to travel thousands of miles underwater without eating? As is often the case, the efficiency (and beauty) of nature’s solutions to common problems far supersede those we’ve developed ourselves.

A recent review by Netta Cohen and Jordan Boyle of the University of Leads (UK) to be published in Contemporary Physics has a nice discussion of the fluid mechanics involved in different models of undulatory locomotion, as presented by various organisms. What becomes clear to someone (me) not in the field, is that for something seemingly as simple as getting around in a fluid, we know pretty much exactly how the most efficient organisms do it but are a good ways from being able to replicate it well ourselves.

Towards the end of the paper, the authors discuss the emerging technologies of undulatory robotics, on both the meter scale (robotic snakes for searching for people in building rubble) and on the micrometer scale (robotic worms to swim through an artery to image tissue injury or healing progress). These applications are an interesting glimpse at an area of research ripe for development.

The propeller (which itself is of biological origin) on the back of a boat has gotten us a good, long way, but it has a number of limitations. For one, it’s quite inefficient compared to biological undulation; although, it’s significantly simpler to implement mechanically. As our material science and coordination of many mechanical movements (think how many independent muscles a fish must move to flap its body once) continues to improve, our ability to implement this form of locomotion will improve. (Perhaps in 100 years I’ll be able to take a ride in a flagella-powered boat.

A tangent
At the risk of being cliche, I’m again struck by the resourcefulness of evolution in using the tools it has available to perform a task, rather than trying to reinvent the wheel every time. So, the cells in your bronchiole tubes would like a way to move mucus and dirt up and out of the lungs? Well, why not just use oar-like cilia that many paramecium use? A less practical builder (us, perhaps) would expensively go about designing an entire new apparatus. In fact, many of the tools used by evolution (if random chance can be given some agency) are imperfect (for example, the skeletal structure of bat wings vs. bird wings), but they work well enough. This imperfect-but-good-enough usage of biological tools, by the way, is one of the best arguments (if you entertain the argument at all) against so-called intelligent design.

Advertisements

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s

%d bloggers like this: