The science of necrobotix: When scientists turn dead spiders into "robots"

Although the lifespan of this type of robot is short, this work is not without an environmental benefit, which is that spiders are biodegradable, so using them as robotic parts will reduce the amount of waste generated by the robots.

At a time of increasing concern about robots as a result of a robot recently breaking the finger of a 7-year-old child during a chess match in Moscow, researchers from the American "Rice University" presented new research showing a robot whose design is based primarily on a dead spider.

According to the study , published in the journal "Advanced Science" on July 25, the dead spider robot moves and grabs things like a "zombie" just out of a science fiction movie.

Turning dead spiders into robots might be a terrifying scenario idea, but in fact the trend could have tangible benefits. For example, spiders' legs can grip large, delicate, and irregular objects firmly and gently without breaking them.

The science of "necrobotie"

The story began when Fei Yap, a graduate student in mechanical engineering at Rice University, saw a dead spider in the hallway, and made her think about whether it could be used as a robotic element. So, I teamed up with mechanical engineer Daniel Preston, and they figured out a way to make a dead wolf spider's legs cling to things. They called this new type of robotics "Necrobotics".

Lupus spiders have a huge body and thin legs, and they catch the prey with the front feet and then smash their prey with two front dogs covered with hair. Oddly enough, their legs do not have muscles to stretch, but instead move their legs by means of hydraulic pressure, because the spider has a so-called "cephalothorax" and consists of the head and chest fused together, and it contracts and sends internal body fluids to the legs, making it stretch.

So, the team inserted a needle into the vertical thorax chamber and closed the tip of the needle with a spool of glue. The pressure with a small puff of air through the syringe was enough to activate the spider's legs, achieving full range of motion in less than one second.

"We took the spider and put the needle in it without knowing what was going to happen," Yap says in a video. "We had an estimate of where we wanted to put the needle in. And when we did, we got it right the first time," she says.

The team was able to make the dead spider grab a small ball and used this experiment to determine the peak grip strength. Next, the team members used a dead spider to pick up the tiny objects. They also showed that the spider could bear the weight of another spider of roughly the same size.

Necrobotics applications and disadvantages

Preston's lab specializes in soft robotic systems that often use unconventional materials, as opposed to hard plastics, metals and electronics. "These soft robots are so much fun because we use previously untapped types of machining and materials," Preston said.

While most components of human-made robots are very complex, spiders are also complex, but they are abundant. "The concept of necrobotics proposed in this work takes advantage of unique designs found in nature that can be complex or even impossible to artificially replicate," the researchers say in their paper.

"One of the applications where we could see this work used is micromanipulation, and that could include things like microelectronic devices," Preston says.

But one of the drawbacks of a dead spider's clutch is that it begins to wear out after two days or after a thousand open and close cycles. The researchers experimented with coating tarantulas with beeswax and found that their mass drop was 17 times less than that of an uncoated spider over 10 days, which means it retains more water and its hydraulic system may operate for longer.

"We think this is related to issues with dry joints," Preston explains. "And we think we can overcome that by applying polymeric coatings."

Although the use of this type of robots is short, this work is not without an environmental benefit, which is that spiders are biodegradable, so using them as robotic parts will reduce the amount of waste generated by the robots.

"Although it looks like it has come back to life, we're pretty sure it's not alive, and in this case we're using it strictly as a substance derived from a once-living spider... It gives us something really useful," Preston said.