Inflating Spider Corpse Creates Robotic Claw Game Of Nightmares

Preston Innovation Lab

Shortly after the Preston Innovation Lab was established at Rice University, graduate student Faye Yap was rearranging some things when she noticed a dead spider curled up in the hallway. Curious to know why spiders curl up when they die, she did a quick search to find the answer. And that answer - essentially, internal hydraulics - led to a deliciously morbid inspiration: why not use the bodies of dead spiders as tiny pneumatic grippers to grab and maneuver tiny electronic parts?

Yap and his colleagues, including councilman Daniel Preston, did just that. They turned a dead wolf spider into a grasping tool in one assembly step, essentially starting a new area of ​​research they cheekily dubbed "necrobotics." They described the process in detail in a new paper published in the journal Advanced Science. The authors suggest that the gripper could be ideal for delicate repetitive "pick-and-place" tasks and could possibly be used one day in microelectronics assembly.

Preston's lab specializes in so-called soft robotics, which eschews the usual hard plastics, metals and electronics in favor of more non-traditional materials. Hydrogels and elastomers, for example, can serve as actuators powered by chemical reactions, pneumatics, or even light. Roboticists have also long found inspiration for their designs in nature, studying the locomotion of animals such as cheetahs, snakes, insects, starfish, jellyfish and octopuses. (See, for example, our article on the development of the OctaGlove, designed to grip slippery objects underwater.)

Enlarge / An illustration shows the process by which mechanical engineers at Rice University transform dead spiders into necrobotic claws, capable of grasping objects when triggered by hydraulic pressure. Preston Innovation Lab

Count spiders among these creatures that continue to fascinate and inspire robotics, thanks to the way their bodies incorporate both rigid and soft components. There's also the unique way they control their legs. "Spiders don't have pairs of antagonistic muscles, like biceps and triceps in humans," Yap said. “They only have flexor muscles, which allow their legs to bend, and they extend them outwards by hydraulic pressure. When they die, they lose the ability to actively pressurize their bodies. That's why they cower. We wanted to find a way to take advantage of this mechanism."

Ancient researchers have designed spider-inspired tires, joints, and muscles, but manufacturing these components on such a small scale usually requires several painstaking steps. There are also biohybrid systems based on living or active biological materials, but Yap et al. note that these require meticulous and precise maintenance. A memorable article reported controlling a live spider with electrical stimulation, and scientists found uses for spider silk and molted spider exoskeletons. But overall, "the incorporation of biotic materials derived from the spider's body itself has yet to be explored," the authors wrote.