It makes sense considering evolution, but nature comes up with lots of different ways to do things. Consider moving. Land animals walk on four feet or two, some jump, and some use peristalsis or otherwise slither. Oddly, though, mother nature never developed the wheel (although the mother-of-pearl moth’s caterpillar will form its entire body into a hoop and roll away from attackers). Human-developed robots which, on the other hand, most often use wheels. Even a tank track has wheels within. [Joesinstructables] latest robot still uses wheels, but it emulates the slithering motion of a snake, He calls it the Lake Erie Mamba.
The most interesting thing about the robot is that it can reconfigure and move in several different modalities. Like the caterpillar, it can even form a wheel like an ouroboros and roll. You can see that at the end of the video, below.
The base configuration slithers and uses 12 segments, each containing a servo motor. [Joe] uses a key fob remote to drive the snake, although it can move by itself, too. The brains are — what else — an Arduino. In some configurations, the snake carries its own brain and power. In others, there’s a scary-looking wiring harness necessary when the snake becomes a wheel because it has no room in that configuration for the extra items.
Real snakes have different ways they move, and so does the Lake Erie Mamba. In the slithering configuration, passive wheels convert a sine or cosine wave motion into linear motion. [Joe] explains the math behind the motion. If you take off the passive wheels, the snake can move like an inch worm. Turning is complicated in this mode since it can only go forward or backward without some changes. The segments can reconfigure to put a drive wheel in play to introduce the desired lateral motion.
Real snakes can combine the two kinds of motion to “sidewind” and the Mamba can do that too. This does require reconfiguration of the segments and driving some segments with a sine wave and others with a cosine wave.
This isn’t the first time we’ve seen the ouroboros trick. If you think robotic snakes couldn’t possibly be useful, think again. Of course the modular robot that captured our hears is Dtto, which claimed the Grand Prize in last year’s Hackaday Prize.