April 24, 2013 02:47pm ETBaby Sea Turtles Inspire Flippered Robot Georgia Tech associate professor Daniel Goldman and researcher Nicole Mazouchova watch FlipperBot move through a bed filled with poppy seeds. Credit: Georgia Tech/ Gary Meek View full size image

Flippered robots inspired by sea-turtle hatchlings could shed light on how the ancestors of terrestrial animals first evolved to crawl on land, researchers say.

Such research could also lead to amphibious robots that can tackle both land and sea, investigators added.

Scientists are designing robots that can go where humans cannot or should not go, and often rely on inspiration from nature to do so. For instance, snakelike robots could, in principle, slither into crevices to help find disaster victims.

Challenging environments for robots to cross include sand, gravel, soil, mud and other unstable granular surfaces that can deform around legs in complex ways. To learn new ways to navigate such ground, Daniel Goldman, a physicist at the Georgia Institute of Technology in Atlanta, and his colleagues investigated sea-turtle hatchlings.

"These little turtles are remarkably effective at moving over solid ground, with limbs designed for moving in fluid," Goldman told TechNewsDaily.

The researchers analyzed 25 baby loggerhead sea turtles from nests on Jekyll Island, one of Georgia's coastal islands, at night. They investigated how the turtles crawled on tracks of beach sand housed in a truck parked near the beach, video-recording them as they moved in the darkness toward a light that simulated the moon. [See also: 10 Animal-Inspired Robots]

Goldman and his colleagues Nicole Mazouchova and Paul Umbanhowar were surprised to learn the hatchlings moved about as quickly on soft sand as they did on hard sand.

"The turtles insert their flippers just deep enough into soft sand so that the material does not yield behind the flipper as they move," Goldman said. "That means the sand doesn't flow around the flippers, and they don't slip — so they can propel themselves."

The key to performing well, regardless of the conditions of the sand, seemed to lie in how the turtles controlled their wrists.

"On hard ground, their wrists locked in place, and they pivoted about a fixed arm," Goldman said. "On soft sand, they put their flippers into the sand, and the wrist would bend as they moved forward. We decided to investigate this using a robot model."

These findings led to the development of FlipperBot, the first robot to employ flippers against malleable surfaces. The small droid is about 7.5 inches (19 centimeters) long, weighs 2 lbs. (970 grams), and has two motor-driven flippers with flexible wrists similar to sea turtle wrists

In experiments involving a bed of poppy seeds that simulated sand, the flexible wrist helped FlipperBot minimize slipping while moving forward. The flexible wrist also helped keep the robot's body angled away from the ground, minimizing drag from belly friction that could slow it down.

"It was surprising how sensitive this locomotion was to small changes in how the flippers move," Goldman said. "If you change things — even by a millimeter — it could be enough to make the thing move either well or poorly."

The robot and the turtles often did poorly when their limbs encountered sandy ground that had already been disturbed.

"If the ground the flippers go into was disturbed already, the flippers penetrate more deeply, and that causes the body to not lift as high and the belly to drag more," Goldman said. Successful flipper-based movement may depend on having flexible wrists that allow them to move without disturbing too much sand.

"Very small changes in gait or body structure can cause dramatic decreases in speed," Umbanhowar added.

These findings might help scientists better understand how turtle flippers work — which, in turn, could help build robots designed to both swim through water and walk on land.

"This work can provide fundamental information on what makes flippers good or bad," Goldman said.

In future studies, the robots could also help researchers understand how turtles, and other creatures with limbs designed for swimming, evolved to walk on land.

"We are now working with paleontologists on studying what the first animals moving on land were like with more paleontologically realistic robots," Goldman said. "These animals were not moving on concrete, on hard rock, but likely encountered materiallike sand and mud — which can flow and yield upon footsteps —and their limbs were likely flipperlike."

The robots could also help conserve endangered sea turtles.

"The natural beach habitat of hatchling sea turtles is endangered by human activity," Mazouchova said. "Robot modeling can provide us with a tool to test environmental characteristics of the beach and implement efforts for conservation."

Goldman, Mazouchova and Umbanhowar detailed their findings April 24 in the journal Bioinspiration & Biomimetics.

小海龟激发Flippered机器人创作灵感

2013年4月24日下午2时47分ETBaby海龟启发Flippered Robot 佐治亚理工学院副教授丹尼尔·戈德曼和尼科尔研究员看Mazouchova移动FlipperBot通过一层充满了罂粟种子。图片来源：佐治亚理工学院

加里·米克查看原图

Flippered机器人的灵感来自海小海龟能阐明如何陆生动物的祖先首先进化到爬行的土地上，研究人员说.

这样的研究也导致两栖机器人可以解决陆地和海洋，研究人员添加.

科学家们正在设计的机器人，能去的地方人不能或不应该，常常依赖于大自然的灵感这样做。例如，蛇形机器人可以在原则上，滑行到缝里帮助寻找受灾群众.

挑战性的环境机器人穿越包括沙子，碎石，泥土，泥浆等不稳定颗粒的表面，可变形的腿周围以复杂的方式。要学习新的方法来导航等地，丹尼尔·戈德曼，一个物理学家在乔治亚技术研究所在亚特兰大，和他的同事研究了海小海龟.

u0026 QUOT;这些小龟是非常有效的，在动过坚实的基础，有四肢专为移动流体，与QUOT;高盛告诉TechNewsDaily .

研究人员分析了25宝宝蠵海龟从杰基尔岛，格鲁吉亚沿海岛屿之一的巢，在夜间。他们调查了龟爬在沙滩上的沙子装在停在附近的海滩上货车曲目，视频记录他们，因为他们在朝着光模拟月球的黑暗移动。 [参见：10动物的启发机器人See also: 10 Animal-Inspired Robots只是深足进松软的沙滩使物料不挡板后面产生，因为他们移动，＆QUOT;高盛说。 ＆QUOT;这意味着沙不流周围的??脚蹼，并且它们不打滑＆mdash;这样他们就可以推动自己＆QUOT;

的关键表现良好，无论沙的条件，似乎在于如何海龟控制自己的手腕.

u0026 QUOT;在硬地上，手腕锁定到位，他们绕一固定臂，＆QUOT;高盛说。 ＆QUOT;在柔软的沙滩上，他们把自己的脚蹼进沙，和手腕会弯曲，因为他们前进。我们决定使用机器人模型，以探讨这个＆QUOT;

这些发现导致了FlipperBot的发展，第一台机器人采用对延展性表面的鳍状肢。小机器人是关于7.5英寸（19厘米）长，重2磅（970克），并有两个电机驱动的脚蹼灵活手腕类似于海龟手腕

在涉及床罂粟籽该模拟砂的实验中，挠性腕式帮助FlipperBot最小化滑动而前进。灵活的手腕也有助于保持机器人的身体倾斜离开地面，尽量减少腹部摩擦阻力，可以慢下来.

u0026 QUOT;令人惊讶的这一运动的敏感程度是在怎样的鳍状肢移动的微小变化，与QUOT;高盛说。 ＆QUOT;如果你改变的东西和mdash;甚至一毫米＆mdash;它可能是足以让事物移动或者好或不好＆QUOT;

机器人和龟往往表现不佳时，他们的四肢遇到了已经不安.

u0026 QUOT沙地，如果地面的鳍状肢进入了已经不安的鳍状肢渗透越深，而且会使身体抬不高和肚拖越多，与QUOT;高盛说。成功的鳍型机芯可能取决于其灵活的手腕，让他们不会干扰太多沙子.

u0026 QUOT动;步态或身体结构非常小的变化会引起剧烈的下降速度，与QUOT; Umbanhowar加.

这些发现可能有助于科学家更好地了解海龟的鳍状肢的工作原理和mdash;这反过来，可能有助于建立机器人设计均通过水游泳和在陆地上行走.

u0026 QUOT;这项工作可以提供基本的信息是什么让脚蹼的好坏，与QUOT;高盛表示，.

在未来的研究中，机器人还可以帮助研究人员了解海龟和其他动物肢体专为游泳，演变为在陆地上行走.

u0026 QUOT;我们现在在研究什么，第一动物正与古生物学家移动在陆地上就像有更多的古生物逼真的机器人，＆QUOT;高盛说。 ＆QUOT;这些动物不动了混凝土，在坚硬的岩石，但可能遇到materiallike砂泥＆mdash;它可以流动并且在脚步＆mdash产量和四肢有可能鳍状＆QUOT;

机器人还可以帮助保护濒危的海龟.

u0026 QUOT;对幼体海龟的天然海滩栖息地被人类活动，与QUOT危害; Mazouchova说。 ＆QUOT;机器人模型可以为我们提供一个工具来测试海滩的环境特点和实施保护工作＆QUOT;

高盛，Mazouchova和Umbanhowar在杂志Bioinspiration和放大器详细介绍了他们的发现4月24日;仿生学

,,"Yīng'ér hǎiguī qǐfā Flippered jīqìrén