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The evolution of Blue Ray X-4


This summer, as the world watched video of crude oil gushing into the Gulf of Mexico in what has become the largest oil spill in history, a handful of UNF mechanical engineering students were hard at work perfecting a miniature remote-controlled submarine capable of sending video, taking water samples, plotting data and moving objects underwater, an ambitious project that earned the students international recognition and now has the ability to assist with research in waterways.


At the start of their senior year, Keith Stilson and Shane Kennett needed a project for their Capstone Design course in the College of Computing, Engineering and Construction. After considering a list of projects available to their class, Stilson, Kennett and two other mechanical engineering majors formed the Blue Ray Team and decided to design and build a remotely operated vehicle, or ROV. Their project would be a miniature robotic submarine designed to compete in an international competition and to serve as a research tool for the man who would become their project mentor, Dr. Pat Welsh, director of UNF’s Taylor Engineering Research Institute.


By the time they finished, Stilson and Kennett had left two teammates behind, added a new partner, built four robotic subs, won two design awards, placed fourth in an international underwater robotics competition, earned their degrees and left Welsh with an operable remotely controlled mini-sub for marine and river research.


“They did an exceptional job,” Welsh said. “They exceeded my every expectation in the design of the ROV, greatly exceeded my expectations in the fabrication of the sub, and it’s been a great experience mentoring these guys.”


The challenge from the beginning was to create something that could withstand the pressure of operating underwater and be maneuverable and stable, yet powerful enough to carry out tasks required of a marine research vehicle in the St. Johns River estuary. They were the first UNF students to attempt it. Welsh described it as a tough design problem.


“First off, you’re operating in three dimensions in a very hostile environment,” he said. “You have to deal with pressure, corrosion, water intrusion and, last I checked, water and electronics don’t like each other very much. So it is a real tough design problem to get all that in there. You also have to include buoyancy and stability. It’s not like you’re sitting on a tabletop that’s providing support. You’re in the water in free space.”


Blue Ray X-4, the latest version of the team’s remotely operated submarine, is made of PVC and aluminum, which gives it strength while still being lightweight. It’s about the size of a large microwave oven. It operates with three thrusters, two that propel it through the water and one that facilitates diving and surfacing. It has two grippers to grab or retrieve objects, a high definition camera and an infrared camera that operates in low light conditions, two lights and a hydrophone to detect geological rumblings.


“The evolution of our vehicle has literally gone from the Stone Age to a very sophisticated craft,” Stilson said. “The first circuit was simple, archaic and underpowered. Initially, we were utilizing two-position switches in a makeshift box that would command the sub. Today, we are using two sophisticated circuit boards and a PlayStation controller to operate everything on the submarine.”


The Blue Ray Team spent last fall researching potential solutions, meeting weekly with Welsh to go over their findings, discuss ideas and plan their next steps. Welsh, who spent 20 years in the Navy and even more time around water, said his role mostly was to keep the team from going down blind alleys that he knew wouldn’t work.           


By the start of the spring term, the team had received the mission criteria for the Marine Advanced Technology Education Center Remotely Operated Vehicle (MATE ROV) competition. To succeed in the competition, the sub would have to maneuver into and out of a small dark cave, deploy instruments, take sensor readings, plot data and collect samples. The team divided up the tasks, using the computer-assisted design program NX-IDEAS to design and build parts with a CNC milling machine. They manufactured about 99 percent of the sub from aluminum, PVC, Delrin, marine epoxy and other materials that could withstand the effects of operating in salt water.


Stilson performed the majority of the machine work and fabrication for the sub. He created many of the parts on a lathe, which he had never used prior to the class. Kennett was responsible for the control system. Nick Waytowich joined the team near the end of the year to help finish the project and prepare for the MATE competition. He was responsible for the onboard sensors as well as writing the technical report and creating a poster for the competitions.


The students spent about four months trying to find and modify a motor to put in the thrusters, which took nearly the entire year to develop. As always, water intrusion was the biggest obstacle. It kept getting into the gripper compartment and burning out the servos, small motors that provide control of the grippers through feedback.


The College of Computing, Engineering and Construction provided each team with $300 to develop their capstone projects, but Kennett and Stilson knew after talking with Welsh that the sub would cost much more. They didn’t mind because they had set their sights higher than meeting the standards for the capstone project and spent about $1,500 each developing the first three subs.


“You won’t see that money on the sub,” Stilson said. “It went for research and development,” which meant a lot of trial and error that left them with a graveyard of burned-out servomotors and other discarded failures.


The team regularly took the sub to the UNF Aquatic Center for testing, often returning with burned-out parts.


Perfectionists by nature, Stilson and Kennett aimed high. Their sub topped all capstone projects this year by winning the design award for Mechanical Engineering. The team finished first in the Florida regional MATE ROV competition in April with Blue Ray X-3, qualifying them for the international competition in Hawaii in June. With spring classes already finished, they decided they needed to improve the sub for the international competition.


“There was some stuff about the third one that kind of needed to be ripped apart to fix some things, and Dr. Welsh felt it would be better to build it from scratch and keep the third one in case we didn’t finish the fourth one in time,” Kennett said.


They started work on Blue Ray X-4, spending hundreds of hours in the machine shop and robotics lab to do so. Kennett updated the hardware and software packages from the X-3 for the X-4. Stilson manufactured a new hull, thrusters, braces, end caps and other parts. In the final week before flying to Hawaii, they worked in shifts 24 hours a day because they all needed access to the ROV and only one person could work on it at a time.


For the X-4, Welsh funded parts and supplies from his professional development account. To travel to Hawaii, the team received financial help from Taylor Engineering, UNF’s Engineering Advisory Council, UNF’s Dean’s Leadership Council and the School of Engineering, Florida Engineering Society and local businesses. They even received a cash donation from former UNF professor Dr. Don Farshing. The assistance covered the cost of shipping Blue Ray X-4 and paid for their trip to the MATE ROV competition in Hawaii, where they finished fourth and won the award for “Design Elegance.”


“One of our goals from the beginning was to build a marketable finished product that looks like you could buy it from a major company. We just never wanted to give up on that,” Kennett said.


Since graduating, Kennett entered a doctoral program in engineering at the Colorado School of Mines. Waytowich began graduate work on a doctoral degree at Old Dominion University. Stilson accepted an engineering job with Sikorsky Aircraft Corp. in West Palm Beach. It didn’t hurt that television and newspaper accounts of the sub appeared at the same time he was interviewing for the job.


Stilson and Kennett said they hope to continue their efforts to develop a commercial prototype of the X-4, which will be on display in the Science and Engineering Building until Welsh takes it out for estuarine research in the local coastal areas.


Now that UNF is now eligible to compete in a higher-level class in next year’s MATE competition, which means developing a sub that uses 48-volt DC power instead of 12, Welsh said he anticipates graduating seniors will attempt to match the Blue Ray team’s success.


“They set the bar really high for the teams who will compete next year,” Welsh said. “First off, they have a great design to look at and learn from. But secondly, they’re going to have to work really hard to beat it.”