오징어와 가리비에서 영감얻은 생태 모방 로봇 VIDEO: Robot Squid and Robot Scallop Showcase Bio-inspired Underwater Propulsion
Robot Squid and Robot Scallop Showcase Bio-inspired Underwater Propulsion
Animals have lots of creative ways of moving through the water, and robots are stealing them
By Evan Ackerman
Illustration showing the flying robot squid using a water jet to propel itself out of the water, glide in mid-air, and dive back into the water.
Illustration showing the flying robot squid using a water jet to propel itself out of the water, glide in mid-air, and dive back into the water. Image: Beihang University
오징어와 가리비에서 영감얻은 생태 모방 로봇 'ICRA 2019'에서 로봇 오징어와 로봇 가리비 발표 오징어와 가리비에서 영감을 얻은 로봇 오징어(Robot Squid)와 로봇 가리비(Robot Scallop)가 개발됐다. ‘IEEE 스펙트럼‘은 지난달 캐나다에서 열린 ’ICRA 2019‘에서 발표된 논문 가운데 오징어와 가리비에서 아이디어를 얻어 개발된 로봇 오징어와 로봇 가리비를 소개했다. 일반적으로 수중에서 동작하는 로봇들은 프로펠러나 지느러미와 같은 장치를 이용해 물속에서 움직인다. 하지만 오징어나 가리비는 제트 엔진처럼 압축된 공기를 분사하는 방식으로 물속에서 뛰쳐나와 공중으로 비상하거나 물속에서 앞으로 전진한다.
하단 첫번째 사진 설명: 로봇 오징어.오른쪽은 지느러미와 팔 부분을 접은 모습 로봇 오징어는 중국 ‘북경항공항천대학(Beihang University,北京航空航天大学)‘ 연구팀이 개발했다. 이 로봇은 오징어처럼 워터젯(waterjet) 방식으로 추진력을 얻어 점프하면서 물밖으로 빠져나온다. 물밖으로 나오면 지느러미와 팔을 펴는 동작으로 비상하는 거리를 늘릴 수 있다. 로봇 오징어의 워터젯은 로봇 앞부분에 있는 실린더에 압축공기를 저장하는 방식으로 힘을 비축하고 있다. 지느러미와 팔은 공기압 액추에이터에 의해 제어된다. 로봇 오징어가 물속에서 실린더의 밸브를 열면 압축 공기가 한꺼번에 분출된다. 물속에서 나와 10~20m의 거리를 날아갈 수 있다. 물속에서 한번 분출하면 10m 정도 이동할 수 있다. 연구팀은 앞으로 밀도가 높은 액체 Co2를 사용해 여러 번의 점프가 가능하도록 한다는 계획이다. 하단 두번째 사진 설명: 로봇 가리비의 작동 방식 로봇 가리비는 스위스 EPFL의 ‘제이미 백(Jamie Paik)’ 교수팀이 개발했다. 가리비는 껍데기를 열었다 닫는 방식으로 앞으로 전진하는 힘을 얻는다. 실제 가리비의 움직에서 아이디어를 얻은 로봇 가리비는 무게 65g이며 초당 16cm의 속도로 이동할 수 있다. 실제 가리비는 물을 분사하는 양과 방향을 조절하는 방식으로 방향을 바꿀 수 있지만 아직 로봇 가리비는 그 정도까지는 아니다. 앞으로 방향을 전환하는 기술을 구현한다는 계획이다. 장길수 ksjang@irobotnews.com 로봇신문사 |
edited by kcontents
Most underwater robots use one of two ways of getting around. Way one is with propellers, and way two is with fins. But animals have shown us that there are many more kinds of underwater locomotion, potentially offering unique benefits to robots. We’ll take a look at two papers from ICRA this year that showed bioinspired underwater robots moving in creative new ways: A jet-powered squid robot that can leap out of the water, plus a robotic scallop that moves just like the real thing.
Robot squid Image: Beihang University
Prototype of the squid robot in (a) open and (b) folded states. The soft fins and arms are controlled by pneumatic actuators.
This “squid-like aquatic-aerial vehicle” from Beihang University in China is modeled after flying squids. Real squids, in addition to being tasty, propel themselves using water jets, and these jets are powerful enough that some squids can not only jump out of the water, but actually achieve controlled flight for a brief period by continuing to jet while in the air. The flight phase is extended through the use of fins as arms and wings to generate a little bit of lift. Real squids use this multimodal propulsion to escape predators, and it’s also much faster—a squid can double its normal swimming speed while in the air, flying at up to 50 body lengths per second.
The squid robot is powered primarily by compressed air, which it stores in a cylinder in its nose (do squids have noses?). The fins and arms are controlled by pneumatic actuators. When the robot wants to move through the water, it opens a value to release a modest amount of compressed air; releasing the air all at once generates enough thrust to fire the robot squid completely out of the water.
The jumping that you see at the end of the video is preliminary work; we’re told that the robot squid can travel between 10 and 20 meters by jumping, whereas using its jet underwater will take it just 10 meters. At the moment, the squid can only fire its jet once, but the researchers plan to replace the compressed air with something a bit denser, like liquid CO2, which will allow for extended operation and multiple jumps. There’s also plenty of work to do with using the fins for dynamic control, which the researchers say will “reveal the superiority of the natural flying squid movement.”
“Design and Experiments of a Squid-like Aquatic-aerial Vehicle With Soft Morphing Fins and Arms,” by Taogang Hou, Xingbang Yang, Haohong Su, Buhui Jiang, Lingkun Chen, Tianmiao Wang, and Jianhong Liang from Beihang University in China, was presented at ICRA 2019 in Montreal.
The EPFL researchers studied the morphology and function of a real scallop (a) to design their robot scallop (b), which consists of two shells connected at a hinge and enclosed by a flexible elastic membrane. The robot and animal both swim by rapidly, cyclicly opening and closing their shells to generate water jets for propulsion. When the robot shells open, water is drawn into the body through rear openings near the hinge. When the shells close rapidly, the water is forced out, propelling the robot forward (c).
RoboScallop, a “bivalve inspired swimming robot,” comes from EPFL’s Reconfigurable Robotics Laboratory, headed by Jamie Paik. Real scallops, in addition to being tasty, propel themselves by opening and closing their shells to generate jets of water out of their backsides. By repetitively opening their shells slowly and then closing quickly, scallops can generate forward thrust in a way that’s completely internal to their bodies. Relative to things like fins or spinning propellers, a scallop is simple and robust, especially as you scale down or start looking at large swarms of robots. The EPFL researchers describe their robotic scallop as representing “a unique combination of robust to hazards or sustained use, safe in delicate environments, and simple by design.”
And here’s how the real thing looks:
As you can see from the video, RoboScallop is safe to handle even while it’s operating, although a gentle nibbling is possible if you get too handsy with it. Since the robot sucks water in and then jets it out immediately, the design is resistant to fouling, which can be a significant problem in marine environments. The RoboScallop prototype weighs 65 grams, and tops out at a brisk 16 centimeters per second, while clapping (that’s the actual technical) at just over 2.5 Hz. While RoboScallop doesn’t yet steer, real scallops can change direction by jetting out more water on one side than the other, and RoboScallop should be able to do this as well. The researchers also suggest that RoboScallop itself could even double as a gripper, which as far as I know, is not something that real scallops can do.
“RoboScallop: A Bivalve-Inspired Swimming Robot,” by Matthew A. Robertson, Filip Efremov, and Jamie Paik, was presented at ICRA 2019 in Montreal.
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