Tag Archives: mechanics

Bots That Build Themselves


Wouldn’t it be a glorious breakthrough if your next furniture purchase could assemble itself? No more sifting though stepwise Scandinavian manuals describing your next “Fjell” or “Bestå” pieces from IKEA; no more looking for a magnifying glass to decipher strange text from Asia; no more searches for an Allen wrench that fits those odd hexagonal bolts. Now, to set your expectations, recent innovations at the macro-mechanical level are not yet quite in the same league as planet-sized self-assembling spaceships (from the mind of Iain Banks). But, researchers and engineers are making progress.

From ars technica:

At a certain level of complexity and obligation, sets of blocks can easily go from fun to tiresome to assemble. Legos? K’Nex? Great. Ikea furniture? Bridges? Construction scaffolding? Not so much. To make things easier, three scientists at MIT recently exhibited a system of self-assembling cubic robots that could in theory automate the process of putting complex systems together.

The blocks, dubbed M-Blocks, use a combination of magnets and an internal flywheel to move around and stick together. The flywheels, running off an internal battery, generate angular momentum that allows the blocks to flick themselves at each other, spinning them through the air. Magnets on the surfaces of the blocks allow them to click into position.

Each flywheel inside the blocks can spin at up to 20,000 rotations per minute. Motion happens when the flywheel spins and then is suddenly braked by a servo motor that tightens a belt encircling the flywheel, imparting its angular momentum to the body of the blocks. That momentum sends the block flying at a certain velocity toward its fellow blocks (if there is a lot of it) or else rolling across the ground (if there’s less of it). Watching a video of the blocks self-assembling, the effect is similar to watching Sid’s toys rally in Toy Story—a little off-putting to see so many parts moving into a whole at once, unpredictably moving together like balletic dying fish.

Each of the blocks is controlled by a 32-bit ARM microprocessor and three 3.7 volt batteries that afford each one between 20 and 100 moves before the battery life is depleted. Rolling is the least complicated motion, though the blocks can also use their flywheels to turn corners, climb over each other, or even complete a leap from ground level to three blocks high, sticking the landing on top of a column 51 percent of the time.

The blocks use 6-axis inertial measurement units, like those found on planes, ships, or spacecrafts, to figure out how they are oriented in space. Each cube has an IR LED and a photodiode that cubes use to communicate with each other.

The authors note that the cubes’ motion is not very precise yet; one cube is considered to have moved successfully if it hits its goal position within three tries. The researchers found the RPMs needed to generate momentum for different movements through trial and error.

If the individual cube movements weren’t enough, groups of the cubes can also move together in either a cluster or as a row of cubes rolling in lockstep. A set of four cubes arranged in a square attempting to roll together in a block approaches the limits of the cubes’ hardware, the authors write. The cubes can even work together to get around an obstacle, rolling over each other and stacking together World War Z-zombie style until the bump in the road has been crossed.

Read the entire article here.

Video: M-Blocks. Courtesy of ars technica.

Biological Gears

We humans think they’re so smart. After all, we’ve invented, designed, built and continuously re-defined our surroundings. But, if we look closely at nature’s wonderful inventions we’ll find that it more often than not beat us to it. Now biologists have found insects with working gears.


From New Scientist:

For a disconcerting experience, consider how mechanical you are. Humans may be conscious beings with higher feelings, but really we’re just fancy machines with joints, motors, valves, and a whole lot of plumbing.

All animals are the same. Hundreds of gizmos have evolved in nature, many of which our engineers merely reinvented. Nature had rotating axles billions of years ago, in the shape of bacterial flagella. And weevil legs beat us to the screw-and-nut mechanism.

The insect Issus coleoptratus is another animal with an unexpected bit of machinery hidden in its body. Its larvae are the first animals known to have interlocking gears, just like in the gearbox of a car.

In high gear

I. coleoptratus is a type of planthoppers – a group of insects known for their prodigious jumping. It takes off in just 2 milliseconds, and moves at 3.9 metres per second. “This is a phenomenal performance,” says Malcolm Burrows of the University of Cambridge. “How on earth do they do it?”

Burrows first ran into the larvae of I. coleoptratus in a colleague’s garden. “We were poking around and there were these bugs, jumping around like crazy.” He took a closer look, and noticed that each larva had meshing gears connecting its two hind legs. The gears had been seen before, by a German biologist called K. Sander, but his 1957 paper isn’t even on the internet.

The bulb at the top of each hind leg has 10 to 12 teeth, each between 15 and 30 micrometres long. Effectively, each hind leg is topped by a biological cog, allowing the pair to interlock, and move in unison.

Working with Gregory Sutton of the University of Bristol, UK, Burrows filmed the gears at 5000 frames per second and confirmed that they mesh with each other (see video, top).

Great timing

The two hind legs moved within 30 microseconds of each other during a jump. Burrows and Sutton suspect that the gears evolved because they can synchronise the leg movements better and faster than neurons can.

Other animals have gears, but not gears that mesh, says Chris Lyal of the Natural History Museum in London. “When you look at [I. coleoptratus‘s gears], you wonder, why can’t anything else do that?” he says.

The German study from 1957 claims that all 2000-odd planthoppers have gears. “I’ve looked at about half a dozen, and they all have them,” says Burrows. “I’d be hesitant to say no other animal has them,” says Burrows. “But they haven’t been described.”

Read the entire article here.

Video courtesy of New Scientist.