Continual trudging through the green spaces on campus causes erosion and paths to form.  Several areas on campus, including the Tech Green, have become heavily eroded due to pedestrian foot traffic.  Pedestrian traffic causes the soil to compact and prohibits plant growth.  Compaction of the soil on Tech Green also hinders water from seeping into the underground cistern.  Landscaping has recently put up new signs at these critical areas to remind everyone to use the sidewalks.  This will help keep the grass alive and in good shape for your recreational activities. 

So the next time you are about to take a short-cut through the grass or a landscaped area, please reconsider and use the sidewalks.  And then maybe after class come back, kick your shoes off, and enjoy being outside. 

The theme for this upcoming year’s Earth Day is “TECH for a Greener Future.”  The committee picked the 2013 theme to represent the spirit of Georgia Tech’s entrepreneurial and eco-friendly student body.  The committee is looking for artwork that represents the new theme and encourages everyone to take action.  The winning design will be featured on the Earth Day 2013 T-shirts and marketing materials leading up to the event.

If you have a design for the 16^th Annual Earth Day Celebration, please submit your artwork to Steve Cseplo at steve.cseplo@facilities.gatech.edu.  Further instructions and past winners can be found at www.earthday.gatech.edu/t-shirt.html.  The deadline to submit an entry is 11:59 PM on November 12, 2012.  Also, those interested in joining the Earth Day committee can contact Heartense Hodges-Lawson at heartense.hodges@facilities.gatech.edu.

For more than 10 years, the Office of Facilities Management has been testing low flow water fixtures to reduce the campus’ water consumption. Many of the newer buildings on campus have energy and water efficient bathrooms with automatic faucets and low flow toilets, and now several of the older buildings will be receiving these upgrades as well.

Georgia Tech spends roughly $7,000,000 a year or $19,663 per day for water and sewer services. After several years of drought and cost increases from the City of Atlanta for water and sewer services, Georgia Tech has stepped up its efforts to conserve water and reduce the Institute’s utility costs. GT’s Energy Conservation team recently completed a major urinal replacement project as part of this initiative. 

Lenox Utility Contractors, LLC began this project by replacing the 308 urinals with low flow urinals and electronic flush valves. To estimate how much water was saved, Georgia Tech conducted a usage survey during the week and weekends of 10 academic and support buildings on campus. Caleb Morris, a student researcher from the College of Engineering, not only helped install the units (his father, Buddy Morris, owns Lenox Utility Contractors) but he also conducted the usage survey for Facilities by placing infrared occupancy sensors above the urinals.

“After helping install the urinals, I was a great candidate for carrying out the survey because I was already familiar with the project and I believe it is important to promote the benefits of new water conservation technologies,” said Caleb Morris.

The team estimates that on average, the 308 urinals that were part of this project are flushed 2.2 million times annually and by replacing these urinals with low-flow models, the Institute could save up to 5,300 gallons of water and sewer per day. Over an entire year, that is about as much water as all of the pools in the Aquatic Center at the Campus Recreation Center (1.9 million gallons). This could also result in a savings of $54,000 a year in water and sewer costs. With such a short pay-back period and significant expected savings, Georgia Tech hopes to implement other water conservation projects in the future.

In addition to being ranked among the top ten public universities in the U.S., Georgia Tech is also a leader in utilities management and conservation. Georgia Tech is committed to developing an environmentally friendly campus and as such is committed to responsible water use management through the adoption of new water saving technologies and practices.

Taking a short hop before a big jump could allow spring-based “pogo-stick” 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.

“If we time things right, the robot can jump with a tenth of the power required to jump to the same height under other conditions,” said Daniel Goldman, an assistant professor in the School of Physics at the Georgia Institute of Technology. “In 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.”

The research was reported October 26 in the journal Physical Review Letters. The work was supported by the Army Research Laboratory’s MAST program, the Army Research Office, the National Science Foundation, the Burroughs Wellcome Fund and the GEM Fellowship.

Jumping 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.

The Georgia Tech research into robot jumping began with a goal of learning how hopping robots would interact with complicated surfaces – such as sand, granular materials or debris from a disaster. Goldman quickly realized he’d need to know more about the physics of jumping to separate the surface issues from the factors controlled by the dynamics of jumping.

Inspired 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.

Aguilar 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’s mass. A high-speed camera and a contact sensor measured and recorded the height of each jump.

• Website shows how changes affect jumping

Aguilar 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.

The 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 – and additional analysis revealed what the researchers called the “stutter jump.”

“The preparatory hop allows the robot to time things such that it can use a lower power to get to the same jump height,” Goldman explained. “You really don’t have to move the mass rapidly to get a good jump.”

The 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.

But because it requires longer to perform than a simple jump, the two-step jump may not be suitable for all conditions.

“If you’re 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,” said Goldman. “But if a hazard is threatening, you may need to generate the additional power to make a quick jump to get out of the way.”

For 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.

Goldman’s 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. “What we have learned here can function as a hypothesis for biological systems, but it may not explain everything,” he said.

The 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.

“In physics, we often study the steady-state solution,” Goldman noted. “If we wait enough time for the transient phenomena to die off, then we can study what’s left. It turns out that in this system, we really care about the transients.”

This 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.

CITATION: Aguilar, Jeffrey et al., “Lift-off dynamics in a simple jumping robot,” Physical Review Letters (2012): http://prl.aps.org/abstract/PRL/v109/i17/e174301

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Media Relations Contact: John Toon (404-894-6986)(jtoon@gatech.edu)
Writer: John Toon

The theme for this upcoming year’s Earth Day is “TECH for a Greener Future.”  The committee picked the 2013 theme to represent the spirit of Georgia Tech’s entrepreneurial and eco-friendly student body.  The committee is looking for artwork that represents the new theme and encourages everyone to take action.  The winning design will be featured on the Earth Day 2013 T-shirts and marketing materials leading up to the event. 

If you have a design for the 16^th Annual Earth Day Celebration, please submit your artwork to Steve Cseplo at steve.cseplo@facilities.gatech.edu.  Further instructions and past winners can be found at http://www.earthday.gatech.edu/t-shirt.html.  The deadline to submit an entry is 11:59 PM on November 12, 2012.  Also, those interested in joining the Earth Day committee can contact Heartense Hodges-Lawson at heartense.hodges@facilities.gatech.edu.

The “battle” will group students on multidisciplinary teamsof five members who will work on cases provided by companies over a course offour days. Teams will present three-minute pitches to a jury at the end of thecompetition, where a winner will be chosen.

The Shell-sponsored competition positions itself as anopportunity to network with companies looking for new talent. Studentsinterested should submit an application by Saturday, March 31. Learn more andsign up at www.nrgbattle.com.