Researchers have turned dead spiders into 'necrobots'

Researchers have turned dead spiders into ‘necrobots’


This robot based on a deceased insect could well give ideas to 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 will get along perfectly with the researchers at Rice University in the United States.

It is indeed the slightly crazy idea that germinated in the mind of Faye Yap, a young graduate in mechanical engineering. Together with her colleagues, she managed to transform the remains of a wolf spider into a sort of claw 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 excessively far-fetched. Why on earth would we bother to recycle the corpses of spiders, when engineers are already achieving real feats? The answer is in two words: flexible robotics.

When we talk about robotics, our imagination most often refers us to large metal machines, heavy, cumbersome and clumsy. But since the very end of the 2000s, thanks to dazzling progress in robotics and materials science, we have 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 accomplish tasks that are both varied and above all very delicate. For example, the industry already has manipulators based on flexible parts that allow machines to handle very fragile objects, 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 objective; and it turns out that the anatomy of these spiders is surprisingly well suited to this scenario.

The spider, a marvel of biological engineering

Indeed, arachnids are not equipped with the same muscles as fish, mammals or birds. They don’t have extensor muscles to “unbend” their legs. Instead, they control their appendages with a hydraulic system as found in many industrial machine tools.

By contracting a particular structure called the cephalothorax, they can send pressurized liquid into the legs. The latter therefore behave like a succession of pistons.

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

To test their idea, the researchers therefore chose the most obvious route. They have simply inserted a needle into what was left of the cephalothorax. After sealing the assembly, a simple pressure on the syringe was enough to fold, then to unfold the legs of the dead spider; in fact, they managed to convert it into a real clamp.

They estimated that she could develop a strength of approximately 35 millinewtons ; a very low figure, as one would expect. But this does not mean that 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 anatomical specificities of the spider, he can also grasp it with extreme delicacy. Above all, it is 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, which may be complicated or even impossible to replicate artificially. “, explain the researchers in their paper.

Obviously, as it stands, this concept also suffers from many limitations, particularly at the level of sustainability and some reliability — two essential factors for considering an industrial application. Suffice to say that it is not tomorrow the day before that a company will sort nails or resistors using a dead spider.

But on the other hand, this exploratory work may identify and replicate some of the mechanisms that make spider anatomy work so well, even after death. Researchers will thus be able to try to apply these concepts to current work on 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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