Autonomous technologies are generally developed in laboratories. But they must be tested, modified, and retested in more challenging environments.
Cédric Pradalier, an associate professor at the Georgia Tech-Lorraine campus in Metz, France, is working with aquatic vehicles to achieve exacting autonomous performance.
“I’m an applied roboticist. I bring together existing technologies and test them in the field,” Pradalier said. “Autonomy really becomes useful when it is precise and repeatable, and a complicated real-world environment is the place to develop those qualities.”
Pradalier is working with aquatic robots, including a 4-foot long Kingfisher unmanned surface vessel modified with additional sensors. His current research aim is to refine the autonomous vehicle’s ability to closely monitor the shore of a lake. Using video technology, the craft surveys the water’s edge while maintaining an exact distance from the shore at a consistent speed.
As currently configured, the boat performs a complex mission involving the taking of overlapping photos of the lake’s periphery. It can autonomously stop or move to other areas of the lake as needed, matching and aligning sections of the shore as they change seasonally.
Applications for such technology could include a variety of surveillance missions, as well as industrial uses such as monitoring waterways for pollution or environmental damage.
One of the advantages of autonomy for mobile applications is that a robot never gets tired of precisely executing a task, Pradalier said.
“It would be very tedious, even demanding, for a human to drive the boat at a constant distance from the shore for many hours,” he said. “Eventually, the person would get tired and start making mistakes, but if the robot is properly programmed and maintained, it can continue for as long as needed.”
Graduate students Dmitry Bershadsky and Pierre Valdez of the School of Aerospace Engineering prepare a 16-foot wave adaptive modular vehicle (WAM-V) for testing at Georgia’s Sweetwater Creek State Park.
An autonomous underwater vehicle (AUV) faces unknown and unpredictable environments. It relies on software algorithms that interact with sensors to address complex situations and adapt to unexpected events.
Fumin Zhang, an associate professor in the Georgia Tech School of Electrical and Computer Engineering (ECE), develops software that supports autonomy for vehicles that delve deep into the ocean gathering data. His work is supported by the Office of Naval Research and the National Science Foundation.
“Underwater vehicles often spend weeks in an ocean environment,” Zhang said. “Our software modules automate their operation so that oceanographers can focus on the science and avoid the stress of manually controlling a vehicle.”
The ocean is a challenging and unpredictable environment, he explained, with strong currents and even damaging encounters with sea life. Those who study underwater autonomy must plan for both expected conditions and unexpected events.
Among other things, the team is using biologically related techniques, inspired by the behavior of sea creatures, to enhance autonomous capabilities.
Zhang has also devised an algorithm that analyzes collected data and automatically builds a map of what underwater vehicles see. The resulting information helps oceanographers better understand natural phenomena.
In 2011, a Zhang student team designed and built an AUV from scratch. Working with Louisiana State University, the team used the craft to survey the Gulf of Mexico and assess underwater conditions after a massive oil spill off the U.S. coastline.
Among other novel AUVs developed by Zhang’s team is one constructed entirely of transparent materials. The design is aimed at testing optical communications underwater.
To facilitate underwater testing of AUVs, Zhang and his team have developed a method in which autonomous blimps substitute for underwater vehicles for research purposes. The blimps are flown in a large room, lessening the time needed to work in research pools.
“The aerodynamics of blimps have many similarities to the conditions encountered by underwater vehicles,” Zhang said. “This is an exciting development, and we are going full speed ahead on this project.”
At the Aerospace Systems Design Laboratory (ASDL), numerous Georgia Tech undergraduates are collaborating with professors, research faculty, and graduate students on autonomous vehicle development for sponsors that include the Naval Sea Systems Command (NAVSEA) and the Office of Naval Research (ONR).
For instance, student teams, working with the Navy Engineering Education Center (NEEC), are helping design ways to enable autonomous marine vehicles for naval-surface applications.
This year, the researchers plan to work on ways to utilize past ASDL discoveries in the areas of autonomy algorithms and the modeling of radio frequency behavior in marine environments. The aim is to exploit those technologies in a full-size robotic boat, enabling it to navigate around obstacles, avoid other vehicles, find correct landing areas, and locate sonar pingers like those used to identify downed aircraft.
Among other things, they are working on pathfinding algorithms that can handle situations where radio signals are hampered by the humid conditions found at the water’s surface. They’re developing sophisticated code to help marine networks maintain communications despite rapidly shifting ambient conditions.
In addition to the NEEC research, ASDL undergraduates regularly compete against other student teams in international autonomous watercraft competitions such as RobotX and RoboBoat.
“The tasks in these competitions are very challenging,” said Daniel Cooksey, a research engineer in ASDL. “The performance achieved by both Georgia Tech and the other student groups is really impressive.”
These competitions have inspired other spin-off undergraduate research efforts. In one project, an undergraduate team is developing autonomous capabilities for a full-size surface craft. The resulting vehicle could be used for reconnaissance and other missions, especially at night or in low-visibility conditions.
“Basically, we study the ways in which adding autonomy changes how a vehicle is designed and used,” said Cooksey. “We’re working to achieve on the water’s surface some of the performance that’s being developed for automobiles on land.”
ASDL, which is part of the Daniel Guggenheim School of Aerospace Engineering, is directed by Regents Professor Dimitri Mavris.
Professor Henrik Christensen of the School of Interactive Computing follows a rescue robot designed to guide people to safety in a low-visibility crisis situation such as a fire.
A major goal of today’s autonomous research involves different robots cooperating on complex missions. As part of the Micro Autonomous Systems and Technology (MAST) effort, an extensive development program involving 18 universities and companies, Georgia Tech has partnered with the University of Pennsylvania and the Army Research Laboratory (ARL) on developing heterogeneous robotic groups. The work is sponsored by the ARL.
In the partners’ most recent joint experiment at a Military Operations on Urban Terrain (MOUT) site, a team of six small unmanned ground vehicles and three unmanned aerial vehicles autonomously mapped an entire building. Georgia Tech researchers, directed by Professor Henrik Christensen of the School of Interactive Computing, developed the mapping and exploration system as well as the ground vehicles’ autonomous navigation capability. The University of Pennsylvania team provided the aerial autonomy, and ARL handled final data integration, performance verification, and mapping improvements.
“We were able to successfully map an entire two-story structure that our unmanned vehicles had never encountered before,” said Christensen. “The ground vehicles drove in and scanned the bottom floor, and the air vehicles scanned the upper floor, and they came up with a combined model for what the whole building looks like.”
The experiment used the Omnimapper program, developed by Georgia Tech, for exploration and mapping. It employs a system of plug-in devices that handle multiple types of 2-D and 3-D measurements, including rangefinders, RGB-F computer vision devices, and other sensors. Graduate student Carlos Nieto of the School of Electrical and Computer Engineering (ECE) helped lead the Georgia Tech team participating in the experiment.
The research partners tested different exploration approaches. In the “reserve” technique, robots not yet allocated to the scanning mission remained at the starting locations until new exploration goals cropped up. When a branching point was detected by an active robot, the closest reserve robot was recruited to explore the other path.
In the “divide and conquer” technique, the entire robot group followed the leader until a branching point was detected. Then the group split in half, with one robot squad following the original leader while a second group followed their own newly designated leader.
In other work, mobile robots’ ability to search and communicate is being focused on ways that would promote human safety during crisis situations. Technology that can locate people in an emergency and guide them to safety is being studied by a team that includes GTRI research engineer Alan Wagner, ECE Professor Ayanna Howard, and ECE graduate student Paul Robinette.
Dubbed the rescue robot, this technology is aimed at locating people in a low-visibility situation such as a fire. Current work is concentrated on optimizing how the rescue robot interacts with humans during a dangerous and stressful situation.
When development is complete, the robot could autonomously find people and guide them to safety, and then return to look for stragglers. If it senses an unconscious person, it would summon help wirelessly and guide human or even robotic rescuers to its location.
Eric Johnson, associate professor in the School of Aerospace Engineering, holds a 1.1-pound quadrotor designed and built by his students that can replicate the autonomous navigational and sensing performance of the 200-pound commercial helicopter behind him.