Robots use all sorts of clever techniques to climb. They use
magnets, grippers, gecko feet, electrostatics, and even supersonic jets of
air. It's sort of surprising, then, that the idea of using the most
stereotypically sticky thing in the universe to climb has been (more or
less) ignored until now. Yes, this robot sticks to surfaces with glue.
Technically, what this robot uses is hot-melt adhesive, or HMA. This
is the stuff that comes out of hot glue guns, and it goes from a solid to a
sticky liquid when it's passed through a heating element.As it cools, it
solidifies again. The robot uses this property to temporarily bond its limbs to a vertical surface one by one and hoist
itself up, unsticking itself as it goes by re-heating the blobs of glue that it sets down.
You've probably already thought of several issues that this robot has to deal with. First, it's very, very slow since it
has to wait for the adhesive to cure every time it takes a step — a 90 second process. Second, it leaves a trail of sticky
little glue spots along every surface that it climbs, making its usefulness questionable in many environments. So yes, a few
things need to be addressed, but this technique has a bunch of upsides, too. The biggest one is that glue — being glue —
sticks to just about anything. It doesn't have to be especially rough, especially smooth, or especially magnetic, which
makes it more versatile than the current generation of just about every other robot adhesion system you can think of.
Also, the hot melt adhesive can support a lot of weight, and it can do it completely passively. You don't need to
expend energy once the adhesive sets to keep from falling. The bonding strength of the HMA in its solid state is such
that a four square centimeter little patch can hold a staggering 60 kilograms — easily enough to hold this robot plus a
fairly gigantic payload, most of which is likely going to have to consist of extra sticks of glue.
Robots are quite good at doing very specific tasks.Arguably, doing
very specific tasks are what robots are best at. When you put a robot
into an unknown situation, however, odds are you're not going to have
a design that's optimized for whatever that situation ends up being. This
is where modular robots come in handy, since they can reconfigure
themselves on-the-fly to adapt their hardware to different tasks.
However, Modular Robotics Lab at the University of Pennsylvania has
come up with a wild new way of dynamically constructing robots based
on their CKBot modules: spray foam.
The process starts with a "foam synthesizer cart" that deploys
several CKBot clusters, each consisting of a trio of jointed CKBot
modules. The CKBot clusters can move around by themselves, sort of,
Having a robot that shoots foam is good for lots more than just building other robots. For example, Modlab has
used it to pick up hazardous objects and to quickly deploy permanent doorstops. There's still some work to be done
with foam control and autonomy, but Modlab is already thinking ahead.
"By carrying a selection of collapsible molds and a foam generator, a robot could form end effectors on a task-by-task basis — for example, forming wheels for driving on land, impellers and oars for crossing water, and high aspect
ratio wings for gliding across ravines. Molds could also be made of disposable material (e.g., paper) that forms part of
the final structure. Even less carried overhead is possible by creating ad-hoc molds: making a groove in the ground or
placing found objects next to each other."
With this kind of capability, you could send a bunch of modules and foam to Mars, and then create whatever kind of
robots you need once you get there. With foam that dissolves or degrades, you could even recycle your old robots into
new robots if the scope of the mission changes. Modular robots were a brilliant idea to begin with, but this foam stuff
definitely has the potential to make them even more versatile.
26 SERVO 12.2011