Researchers teach spider to jump with one eye on the robots of the future
This is Kim. Kim is a Regal Jumping Spider or Phidippus regius. As the name suggests, that species of spider is particularly adept at jumping, able to leap six times its body length. This is something that researchers from the University of Manchester were particularly interested in studying when they visited a pet shop to purchase a number of female arachnids for a study.
If the researchers had told the pet shop staff of their plans that day – to train spiders to jump on command – they may have been politely directed to the dog section instead. Or even shown a cat for that matter: pretty much anything is more trainable than a spider. But Kim was an exception, showing spider smarts beyond her species – the only one of the spiders purchased that learned to jump on command, using a custom-made takeoff and landing platform.
“She will jump at the optimal angle, which means that she can understand the challenge that she is presented with,” study researcher, Dr Mostafa Nabawy told the BBC. “And then she can time her jumping performance at take-off to execute a jump that is optimal in terms of energy demand.” High praise indeed.
Filming their own arachnid Olympics on high-tech cameras, the researchers found that the Regal Jumping Spider – or Kim, at least – had a number of distinct jumping styles to suit the occasion. When the platform was nearby, Kim would favour a faster lower trajectory for maximum accuracy. For the full six-body-length jump, Kim switched to an energy efficient leap, and she was quite capable of angling the jump to go higher or lower – though the researchers found her more confident when pouncing downwards.
If you’re watching the GIF above wondering if you could imitate the form and enter the long jump at the 2020 Olympics, it’s worth noting that Kim also fired a silk safety line to the platform before jumping as a form of stablisation, which would likely result in disqualification.
Of course, biologically we’re at a disadvantage too. We already know that spiders can use hydraulic pressure from fluid within their legs to extend their limbs, so one theory was that this hydraulic power was being used to boost muscle power. But 3D CRT scans revealed that Kim was likely using her regular leg muscles with no additional help.
“Our results suggest that whilst Kim can move her legs hydraulically, she does not need the additional power from hydraulics to achieve her extraordinary jumping performance,” said aerodynamics researcher Bill Crowther, a member of the Manchester University team. “Thus, the role of hydraulic movement in spiders remains an open question.”
Interesting – but why the interest in spider jumps?
While interesting from a biological perspective, the researchers’ main interest lies in what spider biology can teach us in the field of robotics. Some robots can jump in terrifying ways, but could they be even more effective with a few tips from the Regal jumping spider?
Potentially. “A jumping spider can leap up to six times its body length from a standing start. The best a human can achieve is about 1.5 body lengths, said Nabawy. “The force on the legs at take-off can be up to five times the weight of the spider – this is amazing and if we can understand these biomechanics we can apply them to other areas of research.”
That’s a big if, and the team’s first attempts and making a simple jumping robot – visible at the end of the video above – was nowhere near as competent as Kim. “Our engineering structural materials are good enough, but it is very difficult to manufacture at this scale,” the video explains. “Furthermore, power and control electronics cannot compete with nature at this scale yet.”
“Yet” is the key word there, and this research will certainly help with the challenge. But for now, at least, nature has the upper hand on robotics.
Image: Dr Mostafa Nabawy, University of Manchester