Why is ants lifting heavy objects many times the body?

(For a special neck, ants don't need 'extreme hopes' to lift heavy objects.

Researchers have found that the neck joints of a popular American field ant can resist the incredible pressure. Such joints can be promoted, future robots simulate the ability to lift heavy ants on both the ground and in space.

These high hopes can help move a rubber tree (like in the song High Hope in The Hold in the Head in 1959, this song won an Oscar for best film song. ), but the real mystery of the legendary power of ant is probably in the tiny neck of this tiny insect.

"Ants are mechanical systems that are really impressive," said Carlos Castro, an assistant professor of aeronautics and aerospace engineering at Ohio State University. ' Before we started the trials, we were subjectively estimated that they could withstand about 1,000 times their body weight, but the truth is much more than that.'

Engineers are studying whether such joints can make future robots capable of lifting heavy objects like ants on the ground and in space.

Other researchers have observed ants in the field for a long time and they guess that they can lift objects that are hundreds of times more than their body weight or can be even heavier, judging based on weight. of leaves or prey they transport. However Castro and his colleagues use a different approach.

They made broken ants into individual parts.

'Like you have to do with any machine system, if you want to know how they work, you have to separate each part,' Castro said. 'In this case it sounds cruel, but we have anesthetized them before doing it.'

Engineers reviewed Allegheny mound (Formica exsectoides) to see if it was like a device they wanted to re-design: They tested the moving parts of this ant species and materials. structure that part.

They chose this particular ant species because this species is widespread in the Eastern United States and can easily acquire this ant species from the university's insect research lab. It is a medium-sized ant species and is not special about the ability to lift things.

They photographed ants with electron microscopes and tomography X-rays. First, ants are placed in a refrigerator to anesthetize, then are placed face down on a specially designed centrifuge to measure the necessary force to deform the neck and eventually break the head off the body. .

The centrifuges work on the same principle as a game called Rotor. In this game, a circular room will rotate until the centrifugal force pins the body into the wall and the player swings out of the stand on the floor. In the case of ants, their heads are glued to the floor of the centrifuges, so when the centrifuges are turned, the part of the ant can be pulled out until their necks are broken.

The centrifuges spin at a rate of hundreds of cycles per second, and are increasing the pressure on ants. At the rotational force corresponding to about 350 times the body weight of ants, ants' neck joints begin to stretch and the body is stretched out. Ants are broken when the force is about 3,400 to 5,000 times their average body weight.

CT scans found, soft tissue structure of the neck and connection of the neck with hard armor of the head and ant body. Electron micrographs show each part of the head joint - neck - chest covered in a strange texture, structures that look like bumps or feathers spreading from different positions.

"Other insects have similar microstructures, and we think they can play some mechanical role ," Castro said. "These microstructures can adjust the way that Soft tissue and exoskeleton are in contact with each other, in order to minimize pressure and optimize mechanical function, they can create friction or brace a moving part against other parts. "

Another important property of the design seems to be the common surface between the soft material of the neck and the hard material of the head. Such a transition often creates a place to focus large pressure, but ants have a gradual transition and classification between materials that increases efficiency - another design feature that may be useful for Artificial design.

'Now that we understand the tolerance limits of these ants and how to react mechanically when it is under a load, we want to find out how it moves. What has kept its head? What changes when ants carry loads in different directions? '.

Someday, this study could lead to the invention of micro-robots that combine hard and soft parts, like the body of ants. Many of today's work involves assembling small robots, individual devices that can work together. However, a difficult problem will appear if researchers try to create large robots based on the same design, Castro explained.

Ants are super strong species on a small scale because their bodies are too light. Inside their hard outer bones, their muscles do not need to support much, so they can freely use all their strength to lift other objects. People are the opposite, carrying relatively heavy loads due to their own body weight. With human muscles adding body weight, we don't have much strength to lift other objects.

On a scale of human size, though, the ants won with basic physics. Their body weight increases with their overall volume, while their muscular strength only increases with surface area. So a person is as small as ant, if it is true, not in a horror movie, it may not be possible to carry heavy things like ants.

"A large-sized robot based on that design can move and pull goods in a gravityless state, so one day we can design a giant ant robot in space, or at least most is something inspired by ants , "Castro said.

Meanwhile, engineers will study the mechanics of ants thoroughly - perhaps using magnetic resonance images. Computer simulations will also help answer the question of how to scale up similar structures.

Blaine Lilly, a professor of mechanical and aerospace engineering, began this research work with Vienny Nguyen alumni. Nguyen earned a master's degree with this project, and now Nguyen is a robot engineer at Johnson Space Center, where she is helping to design the Valkyrie robot for NASA's DARPA Robotics Challenge. Nguyen is a Ohio State University student Hiromi Tsuda recently joined Castro's research team, and she is in charge of analyzing the surface texture of ants in more detail. Castro and Lilly also began collaborating with Noriko Katsube, also a professor of mechanical and aerospace engineering, and an expert on the mechanical model of biological materials.