By Evan Ackerman30 Sep 2015 15:40 GMTHarvard's Robot Bee Is Now Also a Submarine Image: Wyss Institute/Harvard University Gone swimmin'.

For the last several years, Harvard has been developing a robot bee. They’ve done some impressive work: their sub-paper-clip-sized, 100-milligram flapping-wing micro aerial vehicle is fully controllable down to a stable autonomous hover. It’s still tethered for power, and there’s no onboard autonomous control, but the robot flaps its wings and flies like an insect, which is awesome.

Tiny robotic bugs have lots of potential for search and rescue, surveillance, and exploration, but what’s been all the rage recently is adaptive multi-modal robotics: robots that can creatively handle a combination of terrains, making them much more versatile. With some exceptions, robots are usually pretty bad at this, and with some exceptions, humans and animals are too. There are ground robots that can handle water, and a few flying robots that aren’t totally helpless on the ground, but so far, we haven’t seen much in the way of flying robots that are good swimmers. 

Yesterday at IROS, Harvard researchers presented a paper describing how they managed to get their robotic bee to swim, which I’m pretty sure is not a thing that even real bees are known for doing. With no hardware modifications at all, Harvard’s RoboBee can fly through the air, crash land in the water, and turn into a little submarine. You know what that means: nowhere is safe from robot bees.

Photo: Wyss Institute/Harvard UniversityHarvard’s RoboBee.

Things to keep in mind about these videos: RoboBee is small enough to sit on the tip of your finger, and light enough that you’d barely feel it if it was. When it flies (or swims), it’s doing so under full control: a motion capture system tracks its position, and sends trajectory commands to the robot. This works in both air and water, and RoboBee’s method of entry (a pitch over, dive, crash, and sink) is deliberate. Also, the hovering at the beginning of the first video below looks a little bit wonky, but that’s because RoboBee still has some water on its wings from previous tests (a more stable hover is shown in that same video, after the diving sequence, and the second video below has more details about the experiments).

The key realization here is that swimming is actually a lot like flying: in both cases, you’re trying to propel yourself through a fluid by moving a wing (or fin) back and forth. To fly (and particularly to hover) you need to do this very quickly, but to swim, it’s a much more relaxed motion. It’s fundamentally the same motion, though, and you can achieve it with the same basic hardware. In the case of RoboBee, to fly in air it flaps its wings at 120 Hz, while to swim in water it flaps its wings at just 9 Hz. Otherwise, three axis torque control is very similar, meaning that the robot can be steered around in the water, too.

One unique problem that RoboBee has with the water entry is that it’s so small that the surface tension of the water is enough to keep it from submerging. This is part of the reason that it has to crash land in water [right] (it also needs to have its wings treated with a surfactant to help it sink). A fully loaded RoboBee (with a battery on board) might be heavy enough to avoid this problem, but at this point, it’s still an issue. Also still an issue is the whole water-air transition, which seems like it’s significantly more difficult than going from air to water, but we’ve been assured that the researchers will be tackling this in future work.

“Hybrid Aerial and Aquatic Locomotion in an At-Scale Robotic Insect,” by Yufeng Chen, E. Farrell Helbling, Nick Gravish, Kevin Ma, and Robert J. Wood from the Wyss Institute for Biologically Inspired Engineering at Harvard University was presented this week at IROS 2015 in Hamburg, Germany.

哈佛大学的机器蜜蜂现在还能潜水

harvard机器人蜜蜂现在也是一个submarine图像：威斯研究所/哈佛大学去游泳和# 39；。在过去的几年里，哈佛一直在开发一个机器人蜜蜂。他们都做了一些令人印象深刻的工作；其子回形针大小，100毫克的扑翼微型飞行器是完全可控的下降到一个稳定的自主悬停。我仍然拴权力；有&rsquo；没有星上自主控制，但机器人拍打着翅膀像昆虫，这是真棒。

微型机器人的错误有很多潜在的搜索和救援，监控，和探索，但与rsquo；的风靡最近的自适应多模态机器人：机器人能创造性地处理相结合的地形，使它们更加灵活。在一些例外情况下，机器人通常是很不好的，并且有一些例外，人类和动物都是如此。有地面机器人可以处理水，和一些飞行机器人是&rsquo；不完全无助于地面，但到目前为止，我们还没有看到太多的&ldquo；飞行机器人是好的游泳方式。 ；< / P >

昨天在IROS，哈佛研究人员发表了一篇论文，描述他们如何设法得到他们的机器人蜜蜂游泳，我在其中；肯定不是一件真正的蜜蜂被称为做。没有在所有的硬件修改，哈佛&rsquo；的robobee可以在空中飞行，在水上迫降，而变成了一个小潜艇。你知道这意味着什么：没有安全从机器人蜜蜂。

photo： ；Wyss研究所/哈佛universityharvard &rsquo；的robobee。<记住这些视频P的事情：robobee是足够小，坐在你的指尖，光照充足，你我几乎感觉不到它；如果它是D。当它飞行（或游泳），真的这样做；完全的控制之下：运动捕捉系统跟踪其位置，并发送指令到机器人轨迹。这部作品在空气和水，和robobee &rsquo；入门的方法（一个音调，跳水，崩盘，沉）是故意的。同时，徘徊在下面 第一视频的开始；看起来有点不靠谱，但那是因为robobee；还有一些水在它的翅膀从以前的测试（一个更稳定的悬停显示在相同的视频，在潜水的序列，和下面的第二个视频 ；有更多的细节 ；关于实验）。

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实现的关键是，游泳其实是很多像飞一样：在这两种情况下，你正在试图推动自己；通过流体的运动机翼（或尾翼）来回。飞（特别是悬停）你需要很快地做到这一点，但游泳，这是一个更宽松的运动。这是从根本上相同； ；运动，虽然，你可以用相同的基本硬件实现。在robobee案例，飞在空气中扇动的翅膀在120赫兹，而在水中游动，它扇动的翅膀在9赫兹。否则，三轴转矩控制是非常相似的，这意味着机器人可以把周围的水，太。

一个独特的问题，robobee与入水是&rsquo；太小，水的表面张力，足以让它淹没。这是一部分的原因，它已经崩溃的土地，水，[权利]（它也和需要有它的翅膀处理与表面活性剂，以帮助它下沉）。一辆满载robobee（船上有一个电池）可能足以避免这个问题，但在这一点上，这仍然是一个问题。还一个问题是整个气水过渡，这似乎&rsquo；的比从空气水更困难，但是我们一直放心；研究人员将解决这个在以后的工作中。

&ldquo；混合气和水的运动在一个规模机器昆虫，&rdquo；由鱼峰陈，E.法瑞尔Helbling gravish，尼克，凯文，和罗伯特J.木材从威斯生物工程研究院的哈佛大学在本周去2015在汉堡，德国。