and his research team call it, for obvious reasons, “The Pill.”
The autonomous underwater vehicle (AUV) they designed is bright yellow, about a meter long and rounded on the ends like a capsule.
“What we wanted was maneuverability in tight spaces. Current AUVs are like airplanes. They can only go in one direction. Our AUV is like a helicopter. It can move forward, backward, up and down and to the sides,” said Ghorbel, the project’s principal investigator and professor of mechanical engineering and of bioengineering at Rice University.
Last spring, Ghorbel successfully tested the swimming robot in the Neutral Buoyancy Lab at NASA’s Johnson Space Center. The test required the construction of an underwater structure to recreate the conditions of an oil tank.
The device has precedents. Ghorbel had already worked on similar AUVs used for inspecting the interiors of large, above-ground oil and chemical storage tanks. These AUVs are fitted with inspection sensors and four pumps that generate thrust for motion. They are designed to inspect the walls, floor and floating roof of oil tanks, looking for cracks, corrosion and metal defects.
“Because we have designed it to have six degrees of freedom, it has thrusters with tight feedback control. For now we keep it on a tether and it’s remotely operated, but the goal is to make it truly autonomous. Its purpose will be to inspect the underwater portions of oil rigs and other equipment, and NASA is interested in a similar robot for use in zero-gravity settings,” Ghorbel said.
Two main design challenges remain to be resolved. The first is robot localization. “The AUV needs to know where it is so it can plan where it wants to go next, especially in a GPS-denied environment,” Ghorbel said.
“And we have to make the robot explosion-proof, for obvious reasons,” he added.
Partial funding for the project comes from the Subsea Systems Institute (SSI), established in 2015 as a Texas Center of Excellence under the RESTORE Act (Resources and Ecosystems Sustainability, Tourist Opportunities, and Revived Economies of the Gulf Coast States). SSI is a collaboration among Rice, the University of Houston and NASA’s Johnson Space Center.