Scientists have turned dead spiders into ‘necrobots’

This robot based on a deceased insect could well provide ideas for researchers working on soft robotics.

What’s the first thing that goes through your mind when you come across a dead spider? If you answered” use it to design a new kind of robotic component you get along perfectly with the researchers at Rice University in the USA.

This is indeed the slightly crazy idea that sprouted in the mind of Faye Yap, a young mechanical engineering graduate. Along with her colleagues, she managed to transform the remains of a wolf spider into a claw of sorts that can be controlled at will. They called this concept “necrobotics”, a contraction of “robotics” and the Greek term νεκρός (death).

A new kind of flexible robot

At first glance, the concept seems far-fetched. Why on earth would we bother recycling the corpses of spiders when engineers are already achieving real-world feats? The answer is in two words: flexible robotics technology.

When we talk about robots, our imagination most often refers us to large metal machines, heavy, cumbersome and clumsy. But since the late 2000s, thanks to the dazzling advances of robotics and materials science, we’ve witnessed the emergence of another archetype; the future now belongs to soft robots (see our article).

They can use the flexibility of their materials to perform tasks that are both varied and, above all, very delicate. For example, industry already has manipulators based on flexible parts that enable machines handle very fragile items such as eggs.

This is just an isolated example; most specialists agree that this approach has enormous and still largely unexplored potential, for example in space exploration (see the NASA video below). The researchers behind this work pursue more or less the same goal; and it turns out that the anatomy of these spiders is surprisingly well-suited to this scenario.

The spider, a marvel of biological engineering

Spindles are not actually equipped with the same muscles as fish, mammals or birds. They do not have extensor muscles to “loosen” their legs. Instead, they control their appendages with one hydraulic system which is found in many industrial machine tools.

By contracting a certain structure called the cephalothorax, they can send fluid under pressure into the legs. The latter therefore behaves like a series of stamps.

And this is a very interesting detail for researchers. Because in theory it means that it is possible control the appendages by playing on a simple mechanical principlewithout having to master all the intricacies of the spider’s nervous system.

To test their idea, the researchers therefore chose the most obvious path. They have merely stuck a needle into what was left of the cephalothorax. After sealing the assembly, a simple push of the syringe was enough to fold and then unfold the legs of the dead spider; in fact, they managed to turn it into a real squeeze.

They estimated that she could develop a strength of approx 35 millinewtons ; a very low number, as one would expect. But that doesn’t mean this concept is devoid of interest.

A line of research full of potential

As it stands, their system already develops enough force to lift small objects like electronic components. Thanks to the spider’s anatomical specificities, he can also grab it with extreme delicacy. And above all, it’s a biodegradable system and extremely simple to set up – much more so than designing such a delicate robotic manipulator, in any case.

The concept of necrobotics proposed in this work takes advantage of nature’s unique inventions that may be complicated or even impossible to replicate artificially. “, the researchers explain in their paper.

It is clear that this concept also suffers from many limitations, especially with regard to sustainability and some reliability — two essential factors for considering an industrial application. Suffice it to say, it’s not tomorrow the day before a company will sort out nails or resistors using a dead spider.

But on the other hand, this exploratory work could identify and replicate some of the mechanisms that make the spider’s anatomy work so well, even after they die. Researchers will thus be able to try to apply these concepts to the current work in soft robotics in the hope of taking this discipline to a new dimension. And all thanks to a simple dead spider!

The text of the study is available here.

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