{"165671":{"#nid":"165671","#data":{"type":"news","title":"Study Shows How a Hopping Robot Could Conserve its Energy","body":[{"value":"\u003Cp\u003EA new study shows that jumping can be much more complicated than it might seem. In research that could extend the range of future rescue and exploration robots, scientists have found that hopping robots could dramatically reduce their power demands by adopting a unique two-part \u201cstutter jump.\u201d\u003C\/p\u003E\u003Cp\u003ETaking a short hop before a big jump could allow spring-based \u201cpogo-stick\u201d robots to reduce their power demands as much as ten-fold. The formula for the two-part jump was discovered by analyzing nearly 20,000 jumps made by a simple laboratory robot under a wide range of conditions.\u003C\/p\u003E\u003Cp\u003E\u201cIf we time things right, the robot can jump with a tenth of the power required to jump to the same height under other conditions,\u201d said \u003Ca href=\u0022https:\/\/www.physics.gatech.edu\/user\/daniel-goldman\u0022\u003EDaniel Goldman\u003C\/a\u003E, an assistant professor in the \u003Ca href=\u0022https:\/\/www.physics.gatech.edu\/\u0022\u003ESchool of Physics\u003C\/a\u003E at the Georgia Institute of Technology. \u201cIn the stutter jumps, we can move the mass at a lower frequency to get off the ground. We achieve the same takeoff velocity as a conventional jump, but it is developed over a longer period of time with much less power.\u201d\u003C\/p\u003E\u003Cp\u003EThe research was reported October 26 in the journal \u003Cem\u003EPhysical Review Letters\u003C\/em\u003E. The work was supported by the Army Research Laboratory\u2019s MAST program, the Army Research Office, the National Science Foundation, the Burroughs Wellcome Fund and the GEM Fellowship.\u003C\/p\u003E\u003Cp\u003EJumping is an important means of locomotion for animals, and could be important to future generations of robots. Jumping has been extensively studied in biological organisms, which use stretched tendons to store energy.\u003C\/p\u003E\u003Cp\u003EThe Georgia Tech \u003Ca href=\u0022http:\/\/crablab.gatech.edu\/pages\/jumpingrobot\/index.html\u0022\u003Eresearch into robot jumping\u003C\/a\u003E began with a goal of learning how hopping robots would interact with complicated surfaces \u2013 such as sand, granular materials or debris from a disaster. Goldman quickly realized he\u2019d need to know more about the physics of jumping to separate the surface issues from the factors controlled by the dynamics of jumping.\u003C\/p\u003E\u003Cp\u003EInspired by student-directed experiments on the dynamics of hopping in his nonlinear dynamics and chaos class, Goldman asked Jeffrey Aguilar, a graduate student in the George W. Woodruff School of Mechanical Engineering, to construct the simplest jumping robot.\u003C\/p\u003E\u003Cp\u003EAguilar built a one-kilogram robot that is composed of a spring beneath a mass capable of moving up and down on a thrust rod. Aguilar used computer controls to vary the starting position of the mass on the rod, the amplitude of the motion, the pattern of movement and the frequency of movement applied by an actuator built into the robot\u2019s mass. A high-speed camera and a contact sensor measured and recorded the height of each jump.\u003C\/p\u003E\u003Cul\u003E\u003Cli\u003E\u003Ca href=\u0022http:\/\/crablab.gatech.edu\/pages\/jumpingrobot\/Demo.html\u0022\u003EWebsite shows how changes affect jumping\u003C\/a\u003E\u003C\/li\u003E\u003C\/ul\u003E\u003Cp\u003EAguilar and Goldman then collaborated with theorists Professor Kurt Wiesenfeld and Alex Lesov, from the Georgia Tech School of Physics, to explain the results of the experiments.\u003C\/p\u003E\u003Cp\u003EThe researchers expected to find that the optimal jumping frequency would be related to the resonant frequency of the spring and mass system, but that turned out not to be true. Detailed evaluation of the jumps showed that frequencies above and below the resonance provided optimal jumping \u2013 and additional analysis revealed what the researchers called the \u201cstutter jump.\u201d\u003C\/p\u003E\u003Cp\u003E\u201cThe preparatory hop allows the robot to time things such that it can use a lower power to get to the same jump height,\u201d Goldman explained. \u201cYou really don\u2019t have to move the mass rapidly to get a good jump.\u201d\u003C\/p\u003E\u003Cp\u003EThe amount of energy that can be stored in batteries can limit the range and duration of robotic missions, so the stutter jump could be helpful for small robots that have limited power. Optimizing the efficiency of jumping could therefore allow the robots to complete longer and more complex missions.\u003C\/p\u003E\u003Cp\u003EBut because it requires longer to perform than a simple jump, the two-step jump may not be suitable for all conditions.\u003C\/p\u003E\u003Cp\u003E\u201cIf you\u2019re a small robot and you want to jump over an obstacle, you could use low power by using the stutter jump even though that would take longer,\u201d said Goldman. \u201cBut if a hazard is threatening, you may need to generate the additional power to make a quick jump to get out of the way.\u201d\u003C\/p\u003E\u003Cp\u003EFor the future, Goldman and his research team plan to study how complicated surfaces affect jumping. They are currently studying the effects of sand, and will turn to other substrates to develop a better understanding of how exploration or rescue robots can hop through them.\u003C\/p\u003E\u003Cp\u003EGoldman\u2019s past work has focused on the lessons learned from the locomotion of biological systems, so the team is also interested in what the robot can teach them about how animals jump. \u201cWhat we have learned here can function as a hypothesis for biological systems, but it may not explain everything,\u201d he said.\u003C\/p\u003E\u003Cp\u003EThe simple jumping robot turned out to be a useful system to study, not only because of the interesting behaviors that turned up, but also because the results were counter to what the researchers had expected.\u003C\/p\u003E\u003Cp\u003E\u201cIn physics, we often study the steady-state solution,\u201d Goldman noted. \u201cIf we wait enough time for the transient phenomena to die off, then we can study what\u2019s left. It turns out that in this system, we really care about the transients.\u201d\u003C\/p\u003E\u003Cp\u003E\u003Cem\u003EThis research is supported by the Army Research Laboratory under cooperative agreement number W911NF-08-2-004, by the Army Research Office under cooperative agreement W911NF-11-1-0514, and by the National Science Foundation under contract PoLS PHY-1150760. The content is solely the responsibility of the authors and does not necessarily represent the official views of the Army Research Laboratory, the Army Research Office or the National Science Foundation.\u003C\/em\u003E\u003C\/p\u003E\u003Cp\u003E\u003Cstrong\u003ECITATION\u003C\/strong\u003E: Aguilar, Jeffrey et al., \u201cLift-off dynamics in a simple jumping robot,\u201d Physical Review Letters (2012): \u003Ca href=\u0022http:\/\/prl.aps.org\/abstract\/PRL\/v109\/i17\/e174301\u0022 title=\u0022http:\/\/prl.aps.org\/abstract\/PRL\/v109\/i17\/e174301\u0022\u003Ehttp:\/\/prl.aps.org\/abstract\/PRL\/v109\/i17\/e174301\u003C\/a\u003E\u003C\/p\u003E\u003Cp\u003E\u003Cstrong\u003EResearch News \u0026amp; Publications Office\u003C\/strong\u003E\u003Cbr \/\u003E\u003Cstrong\u003EGeorgia Institute of Technology\u003C\/strong\u003E\u003Cbr \/\u003E\u003Cstrong\u003E75 Fifth Street, N.W., Suite 309\u003C\/strong\u003E\u003Cbr \/\u003E\u003Cstrong\u003EAtlanta, Georgia\u0026nbsp; 30308\u0026nbsp; USA\u003C\/strong\u003E\u003C\/p\u003E\u003Cp\u003E\u003Cstrong\u003EMedia Relations Contact\u003C\/strong\u003E: John Toon (404-894-6986)(\u003Ca href=\u0022mailto:jtoon@gatech.edu\u0022\u003Ejtoon@gatech.edu\u003C\/a\u003E)\u003Cbr \/\u003E\u003Cstrong\u003EWriter\u003C\/strong\u003E: John Toon\u003C\/p\u003E","summary":null,"format":"limited_html"}],"field_subtitle":[{"value":"Research Finds \u0022Stutter Jump\u0022 Could Improve Performance"}],"field_summary":[{"value":"\u003Cp\u003EA new study shows that jumping can be much more complicated than it might seem. In research that could extend the range of future rescue and exploration robots, scientists have found that hopping robots could dramatically reduce their power demands by adopting a unique two-part \u201cstutter jump.\u201d\u003C\/p\u003E","format":"limited_html"}],"field_summary_sentence":[{"value":"A new study could hopping robots accomplish their missions with less energy."}],"uid":"27303","created_gmt":"2012-10-26 15:25:14","changed_gmt":"2016-10-08 03:13:02","author":"John Toon","boilerplate_text":"","field_publication":"","field_article_url":"","dateline":{"date":"2012-10-26T00:00:00-04:00","iso_date":"2012-10-26T00:00:00-04:00","tz":"America\/New_York"},"extras":[],"hg_media":{"165621":{"id":"165621","type":"image","title":"Study of Jumping","body":null,"created":"1449178936","gmt_created":"2015-12-03 21:42:16","changed":"1475894801","gmt_changed":"2016-10-08 02:46:41","alt":"Study of Jumping","file":{"fid":"195547","name":"jumping-robot5.jpg","image_path":"\/sites\/default\/files\/images\/jumping-robot5_0.jpg","image_full_path":"http:\/\/tlwarc.hg.gatech.edu\/\/sites\/default\/files\/images\/jumping-robot5_0.jpg","mime":"image\/jpeg","size":1496744,"path_740":"http:\/\/tlwarc.hg.gatech.edu\/sites\/default\/files\/styles\/740xx_scale\/public\/images\/jumping-robot5_0.jpg?itok=w6ngPmJZ"}},"165631":{"id":"165631","type":"image","title":"Study of Jumping2","body":null,"created":"1449178936","gmt_created":"2015-12-03 21:42:16","changed":"1475894801","gmt_changed":"2016-10-08 02:46:41","alt":"Study of Jumping2","file":{"fid":"195548","name":"jumping-robot47.jpg","image_path":"\/sites\/default\/files\/images\/jumping-robot47_0.jpg","image_full_path":"http:\/\/tlwarc.hg.gatech.edu\/\/sites\/default\/files\/images\/jumping-robot47_0.jpg","mime":"image\/jpeg","size":1460592,"path_740":"http:\/\/tlwarc.hg.gatech.edu\/sites\/default\/files\/styles\/740xx_scale\/public\/images\/jumping-robot47_0.jpg?itok=oHBvlkpo"}},"165641":{"id":"165641","type":"image","title":"Study of Jumping3","body":null,"created":"1449178936","gmt_created":"2015-12-03 21:42:16","changed":"1475894801","gmt_changed":"2016-10-08 02:46:41","alt":"Study of Jumping3","file":{"fid":"195549","name":"jumping-robot71.jpg","image_path":"\/sites\/default\/files\/images\/jumping-robot71_0.jpg","image_full_path":"http:\/\/tlwarc.hg.gatech.edu\/\/sites\/default\/files\/images\/jumping-robot71_0.jpg","mime":"image\/jpeg","size":1282340,"path_740":"http:\/\/tlwarc.hg.gatech.edu\/sites\/default\/files\/styles\/740xx_scale\/public\/images\/jumping-robot71_0.jpg?itok=Ze3Q6xzh"}},"165661":{"id":"165661","type":"image","title":"Study of Jumping5","body":null,"created":"1449178936","gmt_created":"2015-12-03 21:42:16","changed":"1475894801","gmt_changed":"2016-10-08 02:46:41","alt":"Study of Jumping5","file":{"fid":"195551","name":"jumping-robot143.jpg","image_path":"\/sites\/default\/files\/images\/jumping-robot143_0.jpg","image_full_path":"http:\/\/tlwarc.hg.gatech.edu\/\/sites\/default\/files\/images\/jumping-robot143_0.jpg","mime":"image\/jpeg","size":815195,"path_740":"http:\/\/tlwarc.hg.gatech.edu\/sites\/default\/files\/styles\/740xx_scale\/public\/images\/jumping-robot143_0.jpg?itok=wZYps8FG"}}},"media_ids":["165621","165631","165641","165661"],"groups":[{"id":"1188","name":"Research Horizons"}],"categories":[{"id":"135","name":"Research"}],"keywords":[{"id":"47881","name":"Dan Goldman"},{"id":"7111","name":"dynamics"},{"id":"213","name":"energy"},{"id":"47901","name":"hopping"},{"id":"47891","name":"jump"},{"id":"2023","name":"Jumping"},{"id":"1356","name":"robot"},{"id":"166937","name":"School of Physics"}],"core_research_areas":[{"id":"39521","name":"Robotics"}],"news_room_topics":[],"event_categories":[],"invited_audience":[],"affiliations":[],"classification":[],"areas_of_expertise":[],"news_and_recent_appearances":[],"phone":[],"contact":[{"value":"\u003Cp\u003EJohn Toon\u003C\/p\u003E\u003Cp\u003EResearch News\u0026nbsp; \u0026amp; Publications Office\u003C\/p\u003E\u003Cp\u003E(404) 894-6986\u003C\/p\u003E\u003Cp\u003E\u003Ca href=\u0022mailto:jtoon@gatech.edu\u0022\u003Ejtoon@gatech.edu\u003C\/a\u003E\u003C\/p\u003E","format":"limited_html"}],"email":["jtoon@gatech.edu"],"slides":[],"orientation":[],"userdata":""}}}