Virginia Tech College of Engineering researchers are working on an autonomous boat that could one day quickly explore waterways that are difficult to reach or navigate by boat.
“It can operate in riverine systems where maps are poor and hazards are common,” said College of Engineering graduate student Christian Sonnenburg of Johnson City, Tenn., who is majoring in aerospace and ocean engineering.
The 16-foot unmanned surface vehicle (USV) is equipped with sonar, lasers, and 3-D imaging cameras designed to identify hazards above and below the water, be they natural, such as hurricane damage, or man-made, such as border security issues or the Gulf of Mexico oil spill. The USV is being developed by Virginia Tech associate professors Dan Stilwell and Craig Woolsey and researchers at the U.S. Naval Postgraduate School. The Virginia Tech group is handling technology that would operate above the water’s surface, while naval researchers are working on the submerged portion.
“The technology we’re developing could be used to assist the military with any sort of mission in which human boat operators might not be safe,” said Stilwell, a member of the Bradley Department of Electrical and Computer Engineering. “Potential far-term applications include searching tropical river systems for drug smugglers or quickly surveying an area for potential hazards to navigation. Environmental scientists also can use our technology to survey places such as the Chesapeake Bay. It’s very difficult to operate a boat in some of the bay’s estuaries because the navigable channels are not clearly marked and are known only to fishermen. In some cases, these channels are not navigable at all at low tide.”
Both groups are collaborating to develop advanced planning and control algorithms that will make the USV “smart,” said Stilwell, a core member of the Virginia Center for Autonomous Systems at Virginia Tech.
The craft isn’t ready for live missions yet.
“At this point we can successfully operate in environments that are not too challenging,” Stilwell said. “Next year we hope to extend the range of potential environments to those that are truly challenging, such as numerous water hazards and fast-moving water.”
The research team thus far has received roughly $650,000 in funding for two years of work. A third year of funding is expected soon, Stilwell said.
The USV is undergoing tests at Claytor Lake in Pulaski County, Va., by Stilwell and Woolsey’s research team. The team is made up of graduate students Sonnenburg and Shu Du of Beijing, China, and staff researcher Aditya Gadre of Pune, India. Additional tests have been held on the Pearl River on the Louisiana-Mississippi border.
During tests, the crew remains in a chase boat behind the USV. A fail-safe device can be used if the USV veers off course.
Fishermen and nearby homeowners in Pulaski County have shown obvious interest. “Folks are naturally curious about a boat that drives itself and will sometimes come closer to investigate,” Woolsey said.
A popular question? “How does it work?”
“We use a laser line-scanner,” Stilwell said. “It scans a laser across one plane and tells us the range of anything within that plane. The line-scanner is gimbaled so that we can point the line-scanner in any direction that is useful. We usually keep the line-scanner facing forward with the scan plane parallel to the water. The laser line-scanner is good at identifying objects that are not water, which is exactly what we need to find.”
Operating autonomously on water creates many challenges: In some parts of the world, maps are inaccurate because of flooding cycles. Strong currents can make the USV difficult to control, and hazards such as floating tree limbs can change its direction. “Quickly re-planning the vehicle’s motion once hazards are detected and executing the re-planned motion with precision can be a challenge,” Woolsey said.
Because of that, the boat’s computer constantly takes in new data. “That is its principle mission,” Stilwell said. “This boat would create a detailed map of the environment, surface, and subsurface that manned boats could use later. This would allow manned boats to operate more safely and at much higher speeds since they would no longer fear running into a submerged obstacle.”
Stilwell’s hope: “In a few years, the boats will be able to operate robustly in any environment.”
About the unmanned surface vehicle
2: Years in development
15.7: Feet in length
6.9: Feet in width at its widest point
12: Inches of draft, or the vertical distance between the water line and the bottom of the hull
25: Knots, top speed
12: Volts, battery providing electricity to craft, along with alternator. The vessel has a backup gasoline generator.
70: Ampere hours of battery power
The Virginia Center for Autonomous Systems (VaCAS) is helping to spearhead research to build a 16-foot unmanned surface vehicle with the U.S. Navy.
VaCAS is a research center operating under the Virginia Tech College of Engineering and the Institute of Critical Technology and Applied Science. It facilitates interdisciplinary research in autonomous systems technology spanning every domain: air, land, space, and water.
Faculty members oversee research projects ranging from fundamental control theories to vehicle development to applications for science, security, and commerce.
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