Tag Archives: South Korea
#437741 CaseCrawler Adds Tiny Robotic Legs to ...
Most of us have a fairly rational expectation that if we put our cellphone down somewhere, it will stay in that place until we pick it up again. Normally, this is exactly what you’d want, but there are exceptions, like when you put your phone down in not quite the right spot on a wireless charging pad without noticing, or when you’re lying on the couch and your phone is juuust out of reach no matter how much you stretch.
Roboticists from the Biorobotics Laboratory at Seoul National University in South Korea have solved both of these problems, and many more besides, by developing a cellphone case with little robotic legs, endowing your phone with the ability to skitter around autonomously. And unlike most of the phone-robot hybrids we’ve seen in the past, this one actually does look like a legit case for your phone.
CaseCrawler is much chunkier than a form-fitting case, but it’s not offensively bigger than one of those chunky battery cases. It’s only 24 millimeters thick (excluding the motor housing), and the total weight is just under 82 grams. Keep in mind that this case is in fact an entire robot, and also not at all optimized for being an actual phone case, so it’s easy to imagine how it could get a lot more svelte—for example, it currently includes a small battery that would be unnecessary if it instead tapped into the phone for power.
The technology inside is pretty amazing, since it involves legs that can retract all the way flat while also supporting a significant amount of weight. The legs work sort of like your legs do, in that there’s a knee joint that can only bend one way. To move the robot forward, a linkage (attached to a motor through a gearbox) pushes the leg back against the ground, as the knee joint keeps the leg straight. On the return stroke, the joint allows the leg to fold, making it compliant so that it doesn’t exert force on the ground. The transmission that sends power from the gearbox to the legs is just 1.5-millimeter thick, but this incredibly thin and lightweight mechanical structure is quite powerful. A non-phone case version of the robot, weighing about 23 g, is able to crawl at 21 centimeters per second while carrying a payload of just over 300 g. That’s more than 13 times its body weight.
The researchers plan on exploring how robots like these could make other objects movable that would otherwise not be. They’d also like to add some autonomy, which (at least for the phone case version) could be as straightforward as leveraging the existing sensors on the phone. And as to when you might be able to buy one of these—we’ll keep you updated, but the good news is that it seems to be fundamentally inexpensive enough that it may actually crawl out of the lab one day.
“CaseCrawler: A Lightweight and Low-Profile Crawling Phone Case Robot,” by Jongeun Lee, Gwang-Pil Jung, Sang-Min Baek, Soo-Hwan Chae, Sojung Yim, Woongbae Kim, and Kyu-Jin Cho from Seoul National University, appears in the October issue of IEEE Robotics and Automation Letters.
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#437735 Robotic Chameleon Tongue Snatches Nearby ...
Chameleons may be slow-moving lizards, but their tongues can accelerate at astounding speeds, snatching insects before they have any chance of fleeing. Inspired by this remarkable skill, researchers in South Korea have developed a robotic tongue that springs forth quickly to snatch up nearby items.
They envision the tool, called Snatcher, being used by drones and robots that need to collect items without getting too close to them. “For example, a quadrotor with this manipulator will be able to snatch distant targets, instead of hovering and picking up,” explains Gwang-Pil Jung, a researcher at Seoul National University of Science and Technology (SeoulTech) who co-designed the new device.
There has been other research into robotic chameleon tongues, but what’s unique about Snatcher is that it packs chameleon-tongue fast snatching performance into a form factor that’s portable—the total size is 12 x 8.5 x 8.5 centimeters and it weighs under 120 grams. Still, it’s able to fast snatch up to 30 grams from 80 centimeters away in under 600 milliseconds.
Image: SeoulTech
The fast snatching deployable arm is powered by a wind-up spring attached to a motor (a series elastic actuator) combined with an active clutch. The clutch is what allows the single spring to drive both the shooting and the retracting.
To create Snatcher, Jung and a colleague at SeoulTech, Dong-Jun Lee, set about developing a spring-like device that’s controlled by an active clutch combined with a single series elastic actuator. Powered by a wind-up spring, a steel tapeline—analogous to a chameleon’s tongue—passes through two geared feeders. The clutch is what allows the single spring unwinding in one direction to drive both the shooting and the retracting, by switching a geared wheel between driving the forward feeder or the backward feeder.
The end result is a lightweight snatching device that can retrieve an object 0.8 meters away within 600 milliseconds. Jung notes that some other, existing devices designed for retrieval are capable of accomplishing the task quicker, at about 300 milliseconds, but these designs tend to be bulky. A more detailed description of Snatcher was published July 21 in IEEE Robotics and Automation Letters.
Photo: Dong-Jun Lee and Gwang-Pil Jung/SeoulTech
Snatcher’s relative small size means that it can be installed on a DJI Phantom drone. The researchers want to find out if their system can help make package delivery or retrieval faster and safer.
“Our final goal is to install the Snatcher to a commercial drone and achieve meaningful work, such as grasping packages,” says Jung. One of the challenges they still need to address is how to power the actuation system more efficiently. “To solve this issue, we are finding materials having high energy density.” Another improvement is designing a chameleon tongue-like gripper, replacing the simple hook that’s currently used to pick up objects. “We are planning to make a bi-stable gripper to passively grasp a target object as soon as the gripper contacts the object,” says Jung.
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#435793 Tiny Robots Carry Stem Cells Through a ...
Engineers have built microrobots to perform all sorts of tasks in the body, and can now add to that list another key skill: delivering stem cells. In a paper published today in Science Robotics, researchers describe propelling a magnetically-controlled, stem-cell-carrying bot through a live mouse.
Under a rotating magnetic field, the microrobots moved with rolling and corkscrew-style locomotion. The researchers, led by Hongsoo Choi and his team at the Daegu Gyeongbuk Institute of Science & Technology (DGIST), in South Korea, also demonstrated their bot’s moves in slices of mouse brain, in blood vessels isolated from rat brains, and in a multi-organ-on-a chip.
The invention provides an alternative way to deliver stem cells, which are increasingly important in medicine. Such cells can be coaxed into becoming nearly any kind of cell, making them great candidates for treating neurodegenerative disorders such as Alzheimer’s.
But delivering stem cells typically requires an injection with a needle, which lowers the survival rate of the stem cells, and limits their reach in the body. Microrobots, however, have the potential to deliver stem cells to precise, hard-to-reach areas, with less damage to surrounding tissue, and better survival rates, says Jin-young Kim, a principle investigator at DGIST-ETH Microrobotics Research Center, and an author on the paper.
The virtues of microrobots have inspired several research groups to propose and test different designs in simple conditions, such as microfluidic channels and other static environments. A group out of Hong Kong last year described a burr-shaped bot that carried cells through live, transparent zebrafish.
The new research presents a magnetically-actuated microrobot that successfully carried stem cells through a live mouse. In additional experiments, the cells, which had differentiated into brain cells such as astrocytes, oligodendrocytes, and neurons, transferred to microtissues on the multi-organ-on-a-chip. Taken together, the proof-of-concept experiments demonstrate the potential for microrobots to be used in human stem cell therapy, says Kim.
The team fabricated the robots with 3D laser lithography, and designed them in two shapes: spherical and helical. Using a rotating magnetic field, the scientists navigated the spherical-shaped bots with a rolling motion, and the helical bots with a corkscrew motion. These styles of locomotion proved more efficient than that from a simple pulling force, and were more suitable for use in biological fluids, the scientists reported.
The big challenge in navigating microbots in a live animal (or human body) is being able to see them in real time. Imaging with fMRI doesn’t work, because the magnetic fields interfere with the system. “To precisely control microbots in vivo, it is important to actually see them as they move,” the authors wrote in their paper.
That wasn’t possible during experiments in a live mouse, so the researchers had to check the location of the microrobots before and after the experiments using an optical tomography system called IVIS. They also had to resort to using a pulling force with a permanent magnet to navigate the microrobots inside the mouse, due to the limitations of the IVIS system.
Kim says he and his colleagues are developing imaging systems that will enable them to view in real time the locomotion of their microrobots in live animals. Continue reading