It’s a bird, it’s a plane … it’s a robo-puffin?

Title: It’s a bird, it’s a plane … it’s a robo-puffin? 标题：是鸟，是飞机……是机器海鹦？

Given that water is 1,000 times denser than air, moving through those two mediums requires very different mechanics—or so one might assume. Yet birds like gulls and puffins can plunge into the sea, swim underwater, and leap back into the air to fly away. And now engineers at MIT and EPFL in Lausanne, Switzerland, have designed a robot that can do likewise. 鉴于水的密度是空气的1000倍，人们或许会认为在两种介质中穿行需要截然不同的力学原理。然而，海鸥和海鹦等鸟类却能潜入海中、在水下游泳，并跃回空中飞走。如今，麻省理工学院（MIT）和瑞士洛桑联邦理工学院（EPFL）的工程师们设计出了一款能够实现同样功能的机器人。

The “flapping-wing aerial-aquatic vehicle,” or FAAV, weighs less than 300 grams (about half a pound) and is equipped with a central fuselage, two flexible wings, and a steerable tail. The body contains a battery and a waterproof electric motor that drives a crankshaft, which pumps the wings up and down at preset frequencies. The wings are made of thin membranes that are coated with hydrophobic nanoparticles to help wick away water. And the tail is motorized, enabling it to change its angle to help the robot fly up or dive down. 这种“扑翼式水空两栖飞行器”（FAAV）重量不到300克（约半磅），配备了中央机身、两片柔性机翼和一个可操纵的尾部。机身内装有电池和防水电机，用于驱动曲轴，使机翼以预设频率上下扇动。机翼由薄膜制成，表面涂有疏水纳米颗粒，有助于排开水分。尾部配有电机，可以通过改变角度来帮助机器人向上飞行或向下俯冲。

In experiments carried out in a water tank and at Lake Geneva, a team led by Raphael Zufferey, an assistant professor of mechanical engineering at MIT, identified combinations of wing size, flapping frequency, and tail angle that enable the robot to smoothly transition from swimming to flying. The best results came with medium-size wings that were flexible enough to minimize flapping amplitude in water and also firm enough to keep the robot aloft in the air. 在水箱和日内瓦湖进行的实验中，由麻省理工学院机械工程助理教授拉斐尔·祖弗雷（Raphael Zufferey）领导的团队确定了机翼尺寸、扑动频率和尾部角度的最佳组合，使机器人能够平稳地从游泳过渡到飞行。实验结果表明，中等尺寸的机翼效果最好，它们既足够灵活以减小在水中的扑动幅度，又足够坚固以维持机器人在空中的飞行。

The speeds and flapping frequencies were similar to those used by actual birds, and a pitch of 70 degrees—a relatively steep angle—allowed the robot to make the leap from water to air. Interestingly, although many diving birds paddle their feet to help them take off from the water’s surface, the team found that the bot didn’t need feet at all. 其速度和扑动频率与真实鸟类相似，70度的俯仰角（一个相对陡峭的角度）使机器人能够实现从水面到空中的跃升。有趣的是，尽管许多潜水鸟类依靠双脚划水来帮助它们从水面起飞，但研究团队发现，该机器人根本不需要脚。

The engineers’ results could help pave the way for a new class of drones and vehicles that could fly to and sample from aquatic regions too dangerous for traditional vessels to access. “Our dream vision is for oceanographers, marine biologists, and members of coastal communities to launch this robot from a boat, or from shore, and it would fly close to the area of interest, such as an iceberg or a port facility, or over a pod of whales,” says Zufferey. 工程师们的研究成果可能为研制新型无人机和交通工具铺平道路，这些设备能够飞往传统船只难以进入的危险水域并进行采样。祖弗雷表示：“我们的愿景是让海洋学家、海洋生物学家和沿海社区成员能从船上或岸边发射这种机器人，让它飞近感兴趣的区域，比如冰山、港口设施或鲸群上方。”

“It would dive into the water to take a measurement or collect a sample, and fly back to deliver the data at a fraction of the cost of traditional methods. Then it could go back out to dive for more.” The researchers are now trying to design wings that can turn as well as flap. They will also test the robot’s performance under turbulent conditions, such as swimming in choppy waters and flying through wind. “它能潜入水中进行测量或采集样本，然后飞回并传输数据，成本仅为传统方法的一小部分。之后，它还可以再次出发进行更多潜水任务。”研究人员目前正尝试设计既能扑动又能转向的机翼。他们还将测试机器人在湍流条件下的性能，例如在波涛汹涌的水中游泳和在风中飞行。

Then they hope to deploy the vehicle to help answer questions in ocean science. “One of the major challenges in ocean science is collecting data both frequently and across many locations, which is something this robot could do in the future,” Zufferey says. “You could send this out not just every week, but every hour. It could fly out at high speeds, dive in, fly back, deliver its data, and go back out, multiple times.” 他们希望未来能部署这种飞行器，以帮助解答海洋科学中的问题。祖弗雷说：“海洋科学的主要挑战之一是频繁且多点地收集数据，而这正是该机器人未来能够实现的功能。你可以不只是每周，而是每小时都派它出去。它可以高速飞出、潜入水中、飞回、传输数据，然后多次往返。”