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July 15, 2020
In the movie “Ant-Man”, the main character can reduce his size and travel by flying on the back of an insect. Now researchers at the University of Washington have developed a small, steerable wireless camera that can also be mounted aboard an insect, giving everyone a chance to see a world view of Ant-Man.
The camera, which streams video to a smartphone at a rate of 1 to 5 frames per second, sits on a mechanical arm that can rotate 60 degrees. This allows the viewer to capture a high resolution panoramic shot or track a moving object while expending a minimal amount of energy. To demonstrate the versatility of this system, which weighs about 250 milligrams, about a tenth the weight of a game card, the team mounted it on top of live beetles and insect-sized robots.
The results were published July 15 in Science Robotics.
“We have created a low power, low weight wireless camera system that can capture a first-person view of what is happening from a real live insect or create vision for small robots,” said lead author Shyam Gollakota, associate professor from the University of Washington. at the Paul G. Allen School of Computer Science & Engineering. “Vision is very important for communication and navigation, but it is extremely difficult to do it on such a small scale. As a result, prior to our work, wireless vision was not possible for small robots or insects. “
Typical small cameras, such as those used in smartphones, use a lot of power to capture high-resolution and wide-angle photos, and that doesn’t work at insect scale. While the cameras themselves are lightweight, the batteries they need to support them make the overall system too big and heavy for bugs, or bug-sized robots, to charge. So the team took a biology lesson.
“Like cameras, animal vision requires a lot of power,” said co-author Sawyer Fuller, an assistant professor of mechanical engineering at UW. “It is less important in larger creatures like humans, but flies are using 10-20% of their energy at rest just to feed their brains, most of which is devoted to visual processing. To help reduce the cost “Some flies have a small high-resolution region of their compound eyes. They turn their heads to go where they want to see more clearly, such as chasing prey or a mate. This saves power by having high resolution across their entire field of vision.” .
To mimic an animal’s vision, the researchers used a small ultra-low-power black-and-white camera that can traverse a field of view with the help of a mechanical arm. The arm moves when the equipment applies a high voltage, causing the material to bend and move the camera to the desired position. Unless the team applies more power, the arm remains at that angle for about a minute before relaxing back to its original position. This is similar to how people can keep their heads turned in one direction for only a short period of time before returning to a more neutral position.
“An advantage of being able to move the camera is that you can get a wide-angle view of what’s going on without consuming a large amount of energy,” said co-author Vikram Iyer, a doctoral student in electrical and computer engineering. “We can track a moving object without having to expend energy to move an entire robot. These images also have a higher resolution than if we used a wide angle lens, which would create an image with the same number of pixels divided into a much larger area. “
The camera and arm are controlled via Bluetooth from a smartphone from a distance of up to 120 meters away, just slightly more than a soccer field.
The researchers attached their removable system to the back of two different types of beetles: a pretend death beetle and a Pinacate beetle. Similar beetles are known to carry loads heavier than half a gram, the researchers said.
“We made sure that the beetles could still move properly when they were transporting our system,” said co-author Ali Najafi, a doctoral student in electrical and computer engineering at UW. “They were able to freely navigate the gravel, climb a slope, and even climb trees.”
The beetles also lived for at least a year after the experiment ended.
“We added a small accelerometer to our system to detect when the beetle moves. So it only captures images during that time, “Iyer said. “If the camera is continuously transmitting without this accelerometer, we could record an hour or two before the battery runs out. With the accelerometer, we could record for six hours or more, depending on the activity level of the beetle. “
The researchers also used their camera system to design the world’s smallest powered autonomous ground robot with wireless vision. This insect-sized robot uses vibrations to move and consumes almost the same power that low-power Bluetooth radios need to function.
However, the team found that the vibrations shook the camera and produced distorted images. The researchers solved this problem by causing the robot to stop momentarily, take a picture, and then resume its journey. With this strategy, the system was still able to move 2 to 3 centimeters per second, faster than any other small robot that used vibrations to move, and had a battery life of approximately 90 minutes.
While the team is excited about the potential of lightweight, low-power mobile cameras, the researchers acknowledge that this technology comes with a new set of privacy risks.
“As researchers, we firmly believe that it is really important to put things in the public domain so that people are aware of the risks and so that they can begin to find solutions to address them,” Gollakota said.
Applications could range from biology to exploring new environments, the researchers said. The team hopes that future versions of the camera will require even less power and be battery-free, potentially solar-powered.
“This is the first time that we have a first-person view from the back of a beetle while walking. There are so many questions you could explore, such as how does the beetle respond to the different stimuli it sees in the environment? Iyer said. “But also, insects can traverse rocky environments, which is really challenging for robots on this scale. So this system can also help us by allowing us to view or collect samples of hard-to-navigate spaces. “
Johannes James, a PhD student in mechanical engineering at UW, is also a co-author of this article. This research was funded by a grant from Microsoft and the National Science Foundation.
For more information, contact [email protected].
Label (s): Faculty of Engineering • Department of Electrical and Computer Engineering • Department of Mechanical Engineering • Paul G. Allen School of Computer and Engineering • Sawyer Fuller • Shyam Gollakota