A team at MIT has published work demonstrating a soft robot designed after the humble earthworm. Earthworm locomotion occurs by alternately contracting and extending in waves along the length of their bodies. The MIT folks were able to mimic this using a coil of shape memory alloy wire and pulses of current as actuation. The result is a squishy but rugged robot writhing its way across the floor:
Of course, the most pressing question about this research is can we now also call this dance “The Robot”?
Some cool work out of my old group wasjust published in Advanced Materials. Scientists have been trying to understand the principles underlying the remarkable adhesion of geckos for some time, but the focus had always been on the hierarchical fibrillar microstructure on the gecko’s toe. This new work shows that this microstructure may not be necessary for strong, yet reversible adhesion. Instead, the authors develop a model for adhesion based on the compliance of the mechanisms which lie behind the adhesive pad. Using the model as a guide, they constructed a device based on an adhesive pad attached to a strip of inextensible fabric, capable of holding 700 lbs using a 4″ x 4″ square of dry adhesive. The pad can be unstuck by pulling on the strip in a way which lets the pad peel. This structure echoes the gecko’s own anatomy, where the adhesive skin pads are connected directly to its skeleton using a network of inextensible (but bendable) tendons. This is the first time it’s been shown that such a high load can be supported by a reversible, reusable dry adhesive device. Of course, since this research brings us one step closer to being able to Spider-Man our way up walls, itreceivedquitealotofpress.
It seems like scientists are generally portrayed as the stereotype of the “mad scientist”: male, glasses, lab coat, frizzy hair, etc. Just look at the Google image results for “scientist”. Do you know anyone who’s actually like that? I sure don’t. If this is the image that people have of what a scientist is, then it’s hardly surprising that we have such a disconnect in this country between what science says and how we approach important issues such as health care and the environment. If people think they can’t relate to us scientists as normal human beings, it’s difficult for them to trust our findings, and easy to write us off as “elitists” or “nerds”. How many kids forgo an interest in science because it makes them feel weird or because they don’t feel like they fall into the stereotype of what a scientist is? A while back, Fermilab asked 7th graders to draw pictures of a scientist before and after getting a tour of the facilities. The effect of simply seeing the faces behind all the research was pretty drastic.
It’s easy enough to get people to believe that science is cool (everyone likes explosions, right?), but we still have a problem getting people to believe that scientists are normal. That’s why I love this project by Allie Wilkinson and her team. It shows scientists as everyday people having fun, sporting tattoos, having families, doing cool things, and basically looking like someone kids might want to grow up to be. [Check it out!]
Crafting a good title for your research can be difficult. You need it to sound intriguing, yet still be firmly rooted in the reality and scope of your work. For this reason, research talks are quite often more interesting that you might be led to believe from the title alone, as the speaker has the chance to put their work into context and to communicate its true significance. In addition, titles generally highlight the broader scope of your research rather than making specific claims, which often come across as something of a sales pitch — not the greatest idea in a community that takes pride in its skepticism. What this can mean is that it may be hard to judge exactly what a research presentation is about, and whether or not it is interesting enough to attend.
Magnetic cilia?
This was the case two weeks ago, when Dr. Igor Aronson gave a seminar in my department. From the title of his talk, “Active Magnetic Colloids: from Self-Assembled Swimmers to Simple Robots“, I inferred that his research involved magnetically activated cilia on the surface of microparticles — a neat idea, but one that I had read about before and which did not seem like a terribly promising research avenue. I guess it didn’t help that the image printed on the flyer basically looked like a ciliated particle.
I’m glad I decided not to skip the talk, because the actual research was way cooler than my preconception. Basically, it consists of floating magnetic particles on a fluid surface in the presence of a magnetic field. When the field is static, each particle aligns itself with the field, and the aligned dipoles repel each other, spacing themselves out on the surface of the fluid. When the field is an alternating field, the rapid flipping of the floating particle dipoles allows for some attractive interactions between particles, and they form ordered assemblies of particles which writhe and motor rapidly around the surface of the liquid. (Check out a video here.)
The locomotion of these “snakes” seems to derive from a collective impelling of the liquid at both its ends, due to the oscillatory motions of the particles. If the snake is symmetric, the flows from either end offset, creating a rather efficient-looking pump:
This symmetry can be broken by placing a larger glass bead on one end, which results in roughly straight (OK, at least non-chaotic) locomotion:
When the magnetic particles are positioned at the interface between oil and water, both fluids are impelled by their oscillation, which leads to the formation of “asters”, single annular assemblies of particles. Due to the nature of the flow, larger particles will become trapped at the center of the aster, whose position can be remotely controlled using additional local magnetic fields. (This is what the image on the flyer was actually depicting.)
Looking back, Dr. Aronson’s title was certainly adequate, and not at all inaccurate, but my assumptions about the content of his talk almost led me to skip it to get some work done. However, I’m glad that I attended the talk, as I was able to learn about the really cool phenomenon of magnetic snakes.
