{"550391":{"#nid":"550391","#data":{"type":"news","title":"Robot Helps Study How First Land Animals Moved 360 Million Years Ago","body":[{"value":"\u003Cp\u003EWhen early terrestrial animals began moving about on mud and sand 360 million years ago, the powerful tails they used as fish may have been more important than scientists previously realized. That\u2019s one conclusion from a new study of African mudskipper fish and a robot modeled on the animal.\u003C\/p\u003E\u003Cp\u003EAnimals analogous to the mudskipper would have used modified fins to move around on flat surfaces, but for climbing sandy slopes, the animals could have benefitted from using their tails to propel themselves forward, the researchers found. Results of the study, reported July 8 in the journal \u003Cem\u003EScience\u003C\/em\u003E, could help designers create amphibious robots able to move across granular surfaces more efficiently \u2013 and with less likelihood of getting stuck in the mud.\u003C\/p\u003E\u003Cp\u003ESponsored by the National Science Foundation, the Army Research Office and the Army Research Laboratory, the project involved a multidisciplinary team of physicists, biologists and roboticists from the Georgia Institute of Technology, Clemson University and Carnegie Mellon University. In addition to a detailed study of the mudskipper and development of a robot model that used the animal\u2019s locomotion techniques, the study also examined flow and drag conditions in representative granular materials, and applied a mathematical model incorporating new physics based on the drag research.\u003C\/p\u003E\u003Cp\u003E\u201cMost robots have trouble moving on terrain that includes sandy slopes,\u201d said Dan Goldman, an associate professor in the Georgia Tech School of Physics. \u201cWe noted that not only did the mudskippers use their limbs to propel themselves in a kind of crutching motion on sand and sandy slopes, but that when the going got tough, they used their tails in concert with limb propulsion to ascend a slope. Our robot model was only able to climb sandy slopes when it similarly used its tail in coordination with its appendages.\u201d\u003C\/p\u003E\u003Cp\u003EBased on fossil records, scientists have long studied how early land animals may have gotten around, and the new study suggests their tails \u2013 which played a key role in swimming as fish \u2013 may have helped supplement the work of fins, especially on sloping granular surfaces such as beaches and mudflats.\u003C\/p\u003E\u003Cp\u003E\u201cWe were interested in examining one of the most important evolutionary events in our history as animals: the transition from living in water to living on land,\u201d said Richard Blob, alumni distinguished professor of biological sciences at Clemson University. \u201cBecause of the focus on limbs, the role of the tail may not have been considered very strongly in the past. In some ways, it was hiding in plain sight. Some of the features that the animals used were new, such as limbs, but some of them were existing features that they simply co-opted to allow them to move into a new habitat.\u201d\u003C\/p\u003E\u003Cp\u003EWith Ph.D. student Sandy Kawano, now a researcher at the National Institute for \u0026nbsp;Mathematical and Biological Synthesis, Blob\u2019s lab recorded how the mudskippers (\u003Cem\u003EPeriopthalmus barbaratus\u003C\/em\u003E) moved on a variety of loose surfaces, providing data and video to Goldman\u2019s laboratory. The small fish, which uses its front fins and tail to move on land, lives in tidal areas near shore, spending time in the water and on sandy and muddy surfaces.\u003C\/p\u003E\u003Cp\u003EBenjamin McInroe was a Georgia Tech undergraduate when he analyzed the mudskipper data provided by the Clemson team. He applied the principles to a robot model known as MuddyBot that has two limbs and a powerful tail, with motion provided by electric motors. Information from both the mudskipper and robotic studies were also factored into a mathematical model provided by researchers at Carnegie Mellon University.\u003C\/p\u003E\u003Cp\u003E\u201cWe used three complementary approaches,\u201d said McInroe, who is a now a Ph.D. student at the University of California Berkeley. \u201cThe fish provided a morphological, functional model of these early walkers. With the robot, we are able to simplify the complexity of the mudskipper and by varying the parameters, understand the physical mechanisms of what was happening. With the mathematical model and its simulations, we were able to understand the physics behind what was going on.\u201d\u003C\/p\u003E\u003Cp\u003EBoth the mudskippers and the robot moved by lifting themselves up to reduce drag on their bodies, and both needed a kick from their tails to climb 20-degree sandy slopes. Using their \u201cfins\u201d alone, both struggled to climb slopes and often slid backward if they didn\u2019t use their tails, McInroe noted. Early land animals likely didn\u2019t have precise control over their limbs, and the tail may have compensated for that limitation, helping the animals ascend sandy slopes.\u003C\/p\u003E\u003Cp\u003EThe Carnegie Mellon University researchers, who have worked with Goldman on relating the locomotion of other animals to robots, demonstrated that theoretical models developed to describe the complex motion of robots can also be used to understand locomotion in the natural world.\u003C\/p\u003E\u003Cp\u003E\u201cOur computer modeling tools allow us to visualize, and therefore better understand, how the mudskipper incorporates its tail and flipper motions to locomote,\u201d said Howie Choset, a professor in the Robotics Institute at Carnegie Mellon University. \u201cThis work also will advance robotics in those cases where a robot needs to surmount challenging terrains with various inclinations.\u201d\u003C\/p\u003E\u003Cp\u003EThe model was based on a framework proposed to broadly understand locomotion by physicist Frank Wilczek \u2013 a Nobel Prize winner \u2013 and his then student Alfred Shapere in the 1980s. The so-called \u201cgeometric mechanics\u201d approach to locomotion of human-made devices (like satellites) was largely developed by engineers, including those in Choset\u2019s group. To provide force relationships as inputs to the mudskipper robot model, Georgia Tech postdoctoral fellow Jennifer Rieser and Georgia Tech graduate student Perrin Schiebel measured drag in inclined granular materials.\u003C\/p\u003E\u003Cp\u003EInformation from the study could help in the design of robots that may need to move on surfaces such as sand that flows around limbs, said Goldman. Such flow of the substrate can impede motion, depending on the shape of the appendage entering the sand and the type of motion.\u003C\/p\u003E\u003Cp\u003EBut the study\u2019s most significant impact may be to provide new insights into how vertebrates made the transition from water to land.\u003C\/p\u003E\u003Cp\u003E\u201cWe want to ultimately know how natural selection can act to modify structures already present in organisms to allow for locomotion in a fundamentally different environment,\u201d Goldman said. \u201cSwimming and walking on land are fundamentally different, yet these early animals had to make the transition.\u201d\u003C\/p\u003E\u003Cp\u003EThe project also represents a combination of physics, biology and engineering.\u003C\/p\u003E\u003Cp\u003E\u201cProfessor Goldman and his collaborators are combining physics and engineering prototyping approaches to understand the physical principles that allow animals to move in different environments,\u201d said Krastan Blagoev, program director in the National Science Foundation\u2019s Division of Physics. \u201cThis novel approach to living organisms promises to bring to biological sciences higher predictive power and at the same time uncover engineering principles that we have never imagined before.\u201d\u003C\/p\u003E\u003Cp\u003EIn addition to those already mentioned, the project also included co-first author Henry Astley, a Georgia Tech postdoctoral researcher when the project was done, and Chaohui Gong, a postdoctoral researcher at Carnegie Mellon University.\u003C\/p\u003E\u003Cp\u003E\u003Cem\u003EThis research was supported by the National Science Foundation and the NSF Physics of Living Systems program through grants PHY-1205878, PHY-1150760, CMMI-1361778; the Army Research Office through grant W911NF-11-1-0514, and the Army Research Laboratory MAST CTA program. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation, the Army Research Office or the Army Research Laboratory. The Robotics Collaborative Technology Alliance also supported this work.\u003C\/em\u003E\u003C\/p\u003E\u003Cp\u003E\u003Cstrong\u003ECITATION\u003C\/strong\u003E: Benjamin McInroe, et al., \u201cTail use improves soft substrate performance in models of early vertebrate land locomotors,\u201d (Science, 2016).\u003C\/p\u003E\u003Cp\u003E\u003Cstrong\u003EResearch News\u003C\/strong\u003E\u003Cbr \/\u003E\u003Cstrong\u003EGeorgia Institute of Technology\u003C\/strong\u003E\u003Cbr \/\u003E\u003Cstrong\u003E177 North Avenue\u003C\/strong\u003E\u003Cbr \/\u003E\u003Cstrong\u003EAtlanta, Georgia 30332-0181 USA\u003C\/strong\u003E\u003C\/p\u003E\u003Cp\u003E\u003Cstrong\u003EMedia Contacts\u003C\/strong\u003E: John Toon (404-894-6986) (\u003Ca href=\u0022mailto:jtoon@gatech.edu\u0022\u003Ejtoon@gatech.edu\u003C\/a\u003E) or Ben Brumfield (404-385-1933) (\u003Ca href=\u0022mailto:ben.brumfield@comm.gatech.edu\u0022\u003Eben.brumfield@comm.gatech.edu\u003C\/a\u003E).\u003C\/p\u003E\u003Cp\u003E\u003Cstrong\u003EWriter\u003C\/strong\u003E: John Toon\u003C\/p\u003E\u003Cp\u003E\u0026nbsp;\u003C\/p\u003E","summary":null,"format":"limited_html"}],"field_subtitle":"","field_summary":[{"value":"\u003Cp\u003EWhen early terrestrial animals began moving about on mud and sand 360 million years ago, the powerful tails they used as fish may have been more important than scientists previously realized. That\u2019s one conclusion from a new study of African mudskipper fish and a robot modeled on the animal.\u003C\/p\u003E","format":"limited_html"}],"field_summary_sentence":[{"value":"A new study used a robot to help understand how the first land animals moved about."}],"uid":"27303","created_gmt":"2016-07-04 11:19:27","changed_gmt":"2016-10-08 03:22:04","author":"John Toon","boilerplate_text":"","field_publication":"","field_article_url":"","dateline":{"date":"2016-07-07T00:00:00-04:00","iso_date":"2016-07-07T00:00:00-04:00","tz":"America\/New_York"},"extras":[],"hg_media":{"550231":{"id":"550231","type":"image","title":"Mudskipper","body":null,"created":"1467727200","gmt_created":"2016-07-05 14:00:00","changed":"1475895345","gmt_changed":"2016-10-08 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