It is a well-known fact that an octopus can easily grasp anything that slips out of our hands in the water. In order to transfer the abilities of the bizarre aquatic animals to humans, researchers have now developed a biologically inspired glove. It is equipped with suction cups whose holding power is automatically controlled by a sensor system. Tests show that wet objects can be gripped safely and gently with the “Octa-glove”. The concept has numerous possible applications, say the developers.
Humans are land creatures, so in order to cope in the underwater world, we have to equip ourselves with technology: scuba tanks allow us to breathe, neoprene suits keep us warm and goggles enable us to see. To compensate for another weakness under water, however, there are hardly any effective solutions so far: our hands usually have difficulty gripping wet objects. However, this ability is in demand: rescue divers, underwater archaeologists and many other “aquatic craftsmen” have to handle slippery objects or living beings. In order to hold them tight, the gripping pressure often has to be greatly increased. But sensitive objects or living beings can of course be damaged.
Eight-arm role models in sight
The research team led by Michael Bartlett from Virginia Tech in Blacksburg has therefore now devoted itself to developing a concept that should enable people to be more sensitive in the water. As is so often the case in technology, the scientists were inspired by nature. Specifically, the focus was on the masters of grasping in Poseidon’s kingdom: the octopuses. The key elements of their abilities are known to be suction cups, which are under the control of a sophisticated muscular and nervous system. After the broad outer rim of a suction cup makes contact with a surface, doing so activates the muscles in the cupped area behind the rim. In this way, the suction cups can provide negative pressure with adhesive force. “What is interesting is that the octopuses control their numerous suction cups by processing information from various sensors. So the octopus combines adhesion technology, sensors and controls to manipulate underwater objects,” says Bartlett.
In order to convert the model into a glove concept, the researchers first designed a powerful suction cup system: These are flexible rubber handles fitted with soft membranes that can be activated pneumatically. The developers came very close to the octopus version: The suction cup concept can be attached to flat and curved surfaces. After developing this adhesive system, the scientists addressed the challenge of giving the glove sensitivity. To do this, they equipped it with a series of so-called micro-LIDAR proximity sensors. These optical sensors can detect how close an object is.
Artificial suction cup and nervous system
The suction cups and the LIDAR were then connected via a microcontroller to link object detection to activation of the suction cups, mimicking the nervous and muscular systems of a squid. The scientists then integrated all the elements into a neoprene glove. On each fingertip of this “Octa-glove” there is a suction cup with sensors. “You only have to move your hand in the direction of an object and the glove then automatically takes over the gripping work: the electronics can quickly activate and release the adhesion. This allows you to grab wet or submerged objects without crushing them. And all without the user having to press a single button,” explains Bartlett.
The researchers were able to demonstrate this ability of their concept in a series of tests: the glove can be used to gently lift or grasp objects with many different characteristics. They do not necessarily have to be held: Smaller objects can be picked up with just one finger using the suction cup – more units are then used for larger ones. “These abilities mimic the complex manipulation, perception, and control abilities of cephalopods,” says co-author Ravi Tutika of Virginia Tech. However, the scientists emphasize that further development work is necessary in order to come ever closer to the highly complex performance of the natural models. “Our approach is certainly a step in the right direction, but we still have a lot to learn about the squid before we can reach nature’s full grasping abilities,” said Tutika.
Nevertheless, according to the scientists, interesting potential for the technology is already emerging: An octopus glove could help “craftsmen” in the water to be more sensitive, to make their work easier and to protect sensitive objects or living beings during handling. There could also be potential applications in robotics: the scientists say that technical systems – for example in healthcare or in manufacturing – could use the octopus concept to get a better grip on wet objects.
Source: Virginia Tech, technical article: Science Advances, doi: 10.1126/sciadv.abq1905
Video © Virginia Tech