Ant jaws revolutionise our robots

This work was carried out with the support of UK Research and Innovation.

Robots are already revolutionising our world, from medical procedures to construction. But there is one aspect in particular that dextrous robots currently struggle with: a strong and steady grip. In a bid to resolve this, a group of scientists in Edinburgh have taken inspiration from one of nature’s most resilient and ubiquitous inhabitants: the ant. Marushka Soobben travelled to the Scottish capital to get to grips with this breakthrough…

Marushka - I've always been amazed by ants. Not just the marching, it's what they carry. A single ant can grasp and lift objects many times its own weight, with nothing but two tiny jaws. But what if a robot could do the same? Today's story takes us from the forest floor to the robotics lab, where researchers are turning ant anatomy into cutting-edge gripping technology. It's called AntGrip, and it could be the future of robotic hands. It's all happening at the University of Edinburgh's biorobotics lab, part of a wider push through UKRI to rethink how machines interact with the world around them. To understand the inspiration behind AntGrip, I spoke with Professor Barbara Webb, the scientist who spent decades looking to insects for engineering insight.

Barbara - There are many, many robotics applications that we could have if we could get them to successfully grasp objects. Robots have improved and are being used in a lot more contexts, but it still tends to be a very controlled environment, such as a factory. Or they've improved a lot for their navigation, so they're used for inspection tasks. But if the robots could actually interact with objects, they could do a lot more things. You can think of mining. You can think of environmental clean-up, agriculture. There are a lot of different areas where flexible and robust ability to grasp objects could be useful.

Marushka - Why ants specifically and not any other type of insect?

Barbara - Partly because we already studied ants, so we're familiar with them. But also because ants do handle a huge variety of objects. Many ants are generalists in what they eat, so they'll collect and take back to the nest a huge range of things - from seeds, to bits of other insects, to water, lots of different objects. Within the nest they handle their own larvae and eggs, so they have to deal with soft objects and not damage them. They also build their nests by moving lots of dirt and other structures around. So there are lots of different things they can interact with using the same mandibles as their grasping tools.

Marushka - It's a pretty compelling case, I would say. So how does the tech actually work? Well, if you were brave enough to put your eyes close enough to an ant's jaw, you would spot tiny hairs in its mandibles. Like how the zigzags of a snowshoe allow for better grip on the ice, a thermoplastic polyurethane version of these hairs could hold the key to a better robotic grip. To find out more, I met with the researcher who built it, Mohamed, a postdoc in Barbara's lab.

Mohamed - The usual two-fingered grippers are usually a bit bulky because in order to grasp really, you need to have soft pads. And these soft pads are usually very thick, because you have to have some interaction with the object you're grasping. What we have here is a bit different. Thanks to the hairs inspired by the ants, we can have those pads, but very thin, because the hairs are increasing the friction with the object. But at the same time, it doesn't make the gripper bulky, so it can fit into very tight spaces. Here we're targeting warehouse automation and grasping from shelves and stuff like that.

Marushka - Okay, so it's specifically a two-finger gripper. So if you could explain to me, how does this piece of tech work?

Mohamed - So basically, it's like any other two-finger gripper. It opens and closes on the object that you'd like to grasp. But the whole idea is that, as you can see here, we have very slim fingers, which is very favourable in certain types of automation industries - like picking objects from boxes, and stuff like that, like in Amazon. But then since we have all these hairs inspired by ants, we now don’t have to make a very thick pad. The hairs can do the performance of a thick pad, but without being bulky. So an object, for example, can go inside, while deforming the hairs, but the hairs can actually go inside. Instead, for example, if you have a pad here, it won't be able to do that and the robot will get stuck and it will stop.

Marushka - What are these hairs made out of?

Mohamed - They're made of plastics, basically - a material we call TPU. I won't go into the details now, because that would be too boring. But the idea is that it's flexible, but at the same time it is hard enough so it can support cylindrical objects like this. So when you do some manipulation, it doesn't fall out or dislodge from the gripper itself.

Marushka - And are there different sizes of this gripper?

Mohamed - We can make it big or small, as much as we wish. So it can really work in either case just by adding hairs.

Marushka - Before I left, I asked Barbara one final question about where she saw AntGrip or this kind of bio-inspired robotics going in the future.

Barbara - We have various ideas. So indeed, we think it should work at different scales, and we're exploring what angle the hairs should be at or whether to have a distribution of hairs. What happens if you do thousands of grips? How robust it is. There are various things like that we could test, even with this design. The hairs on the ant itself are actually sensory hairs, so they get tactile information from the hairs as well. So that's something we're also quite interested in, whether we can do some kind of modification that maybe not all the hairs, but at least some of the hairs, give us information about tactile contact. And then we’re just looking at the ant more generally to see, when it does interact with objects, what else is it doing? How is it positioning itself to do the grasp? What information is it getting from its antennae? Is it using its front legs? There's a lot else going on that makes its grasping really robust and flexible.

Marushka - Ants might be tiny, but they're powerful, precise and efficient. And thanks to AntGrip, robots are starting to learn a few of their tricks. I'm Marushka Sooben, and the future of robot grip is looking pretty… ant-astic!