Students Designing Autonomous Mine Hunting Mini-sub
By Chief Petty Officer Austin Mansfield, USN
Special to American Forces Press Service
MONTEREY, Calif., Feb. 12, 1998 Anyone who's ever tried to maneuver a surfboard can attest to the difficulty of keeping balance and direction while being pummeled by waves. Research on submersible vehicles at the Naval Postgraduate School in Monterey, Calif., may soon have that problem beat.
The Phoenix is an autonomous underwater vehicle with an additional feature: It's designed for coastal use. Its computerized navigation system keeps it on course, compensating for the varying effects of tides, currents and waves along shore. This ability makes Phoenix the ideal tool for charting mine locations.
"The most difficult part was interfacing all the components," said Russ Whalen, lab manager on the project. "The various codes have to match up to effectively complete the mission. A Sun Sparc computer tells the other computer what to do. These computers are networked -- linked together like office workstations."
"The software hierarchy mirrors a submarine command structure," said Lt. Cmdr. Jeff Riedel, a doctorate student in mechanical engineering. "It has commanding officer, watch officer and sailor levels."
Just as the crew of a submarine is made up of various job specialties such as sonar technicians and communications specialists, the Phoenix has to incorporate those job functions into one "crew."
Other components include a Global Positioning System device for surface navigation, sonars and aircraft gyros. A different navigation system was necessary for underwater use -- an acoustic, short baseline system with Doppler sonar, a three-axis magnetometer, three angular rate gyros and three accelerometers, Project Director Anthony Healey said.
Student membership in the research group has fluctuated between five and 15 during the eight years of research at the school. More than 100 master's and doctorate students have completed original research theses related to the Phoenix. Students use a real robot to work on unsolved problems, providing them with an irreplaceable research tool for thesis work.
Another tangible benefit of student-aided research is the low expense. The external design of the seven-foot, 400- pound test bed vehicle was created by David Marco, research professor. Since the student labor is essentially free, component costs are the major financial expense. While Phoenix's parts are worth about $100,000, said Marco, a contractor's price would be in the millions.
The investment seems to be paying off.
"We're one of the world's leaders in this field," Healey said. "We're making progress in intelligent control system concepts. We're the first to experimentally verify the performance of a three-level intelligent governing architecture." Healey chaired the 1996 Institute of Electrical and Electronic Engineers conference and organized a two-day workshop on autonomous fault detection in March 1997.
Phoenix's successful research results have enticed and maintained an impressive list of sponsors, including the National Science Foundation, Navy Explosive Ordnance Disposal Technology Division, the Office of Naval Research, and Florida Atlantic University.
Now if someone would only develop an autonomous surfboard.
(Mansfield is a writer at the Naval Postgraduate School.)