AUVSI and ONR’s Xth International Autonomous Underwater Vehicle Competition
Space and Naval Warfare Systems Center
San Diego, California
Under water is the place to be this weekend if you’re an engineering student looking for a challenge. This begoggled midshipman is sharing pool time with the U.S. Naval Academy’s entrant in the 10th annual Autonomous Underwater Vehicle Competition, taking place at the Space and Naval Warfare Systems Center in San Diego. (Man and machine are seen here earlier this month in a dive test on the Annapolis team’s home turf.)
The Naval Academy’s effort goes by the name of Project Stingray, and while it may look like neither stingray nor submarine, it is rigged up to perform a series of aquatic tasks that will determine the winner of the competition. The robot subs–more formally, autonomous underwater vehicles–must take into account a range of factors: computer control, power management, navigation, buoyancy and hydrodynamics.
The AUV-207 Stingray stands ready for duty. The yellow Pelican cases serve as the pressure hulls, and because they are positively buoyant, they were placed high on the frame; the most negatively buoyant component, the Doppler Velocity Log (an RD Instruments 1200 KHz Workhorse Navigator), is placed below. That design was chosen to provide the greatest roll stability, but the sub’s pitch still has to be controlled when it changes depth.
The assembly carries, among other things, two cameras to assist in the Stingray’s computer vision: a forward-looking CMU-2 camera (the white tube at right) and a downward-looking DVT Legend 542C.
What’s inside the Pelican boxes? Among other things, a pair of batteries, one for propulsion and the other for instrumentation. The motherboard is a Technologic TS-7200 single-board computer with a 200MHz ARM-9 processor, 32MB of SDRAM, two RS-232 serial ports, two USB 2.0 ports, Ethernet port and other features. The system uses a 2GB compact flash card for file storage, chosen instead of a disk drive to reduce power and volume requirements and to allow for fast backup.
Success in the competition, put on by the Association for Unmanned Vehicle Systems International and the Office of Naval Research, could bring cash prizes of up to $20,000 and “serious bragging rights,” according to the AUVSI.
Winning the prize money and bragging rights won’t be easy. The robot vessels have to navigate across a large pool following a set course. They must also perform various tasks, including passing through a gate, dropping a marker and releasing a buoy. In addition, the competition’s point system takes into account the craftsmanship applied to the vehicle, along with the technical merit and writing style of the research paper submitted beforehand.
Back to defend its 2006 title is the SubjuGator from the University of Florida. The Floridians built an entirely new sub on the same design for this go-round, using Microsoft’s Robotic Studio for control, simulation and communication with a network of sensors, and upgrading to a single-board Intel Core 2 Duo-based computer running Windows XP.
(To see some of last year’s entrants, click here: “Photos: Robot submarines make waves.”)
The venue for the AUVSI contest is a large pool (more than 30 feet deep at its deepest point) at the Space and Naval Warfare Systems Center in San Diego. The Spawar command there is charged with providing a wide range of information technology resources to U.S. military forces.
On Thursday, the team from Cornell University conducted five pool tests of its Proteus vehicle at the Spawar site. “The marker dropper, treasure grabber, and vision system are performing beyond our expectations,” the team says on its blog.
That marked an improvement from some bumpy test experiences a day earlier at the hotel pool. But the sub’s crew was able to work things out, according to the team blog: “The vehicle’s central computer, Eddy, is ready to direct further vehicle testing. There were tense moments at the pool last night when Eddy’s memory got wet, but after drying out for several hours, Eddy is working again.”
The Proteus team at work on Tuesday after arriving in San Diego. “Our computer’s operating system is based on Debian GNU/Linux,” the Cornell team writes on its Web site. “The vehicle abstraction layer builds a Python language wrapper around all of the shared variables, creating an abstract ‘Vehicle’ object in Python. This Vehicle not only has access to physical sensors which write data to shared memory, but can also create virtual hybrid sensors that combine data from multiple real or simulated sources. This feature allows us to create a new virtual sensor like ‘water depth’ by combining data from the real depth and altitude sensor. It also allows mission code to be tested using data from a simulator which writes data to virtual sensors.”
The Naval Academy’s underwater competitor couldn’t look any different, but it does share a name with this Stingray, from the San Diego iBotics Student Engineering Society. That group unites individuals from area community colleges and universities, including San Diego City College, Southwestern College, San Diego State University and the University of California at San Diego.
The iBotics Stingray features a sleek carbon fiber hull designed to move with hydrodynamic ease; the composite material was chosen as well for its light weight, durability and imperviousness to corrosion.
The brains of the Stingray weren’t always encased in an elegant wrapper. While the hull was being formed, this suitcase housed some of the electronic components. The finished product incorporates a Mini-ITX motherboard and a Voith Control System to handle the propellers. In UAV competitions, the vessels typically have a pair of thrusters mounted horizontally for forward and backward movement, as well as turning, plus another pair mounted vertically so that the sub can change depth.
The iBotics team works on the Voith mounting rings for the Stingray.
Wednesday was the check-in and orientation day for the 2007 AUVSI competition. Then come several days of in-water practice and qualifying runs. The finals are scheduled for Sunday.
This is the Seawolf II from North Carolina State University, seen here in a photo from 2006, shortly after last year’s competition, when the NC State team finished ninth.
The battery-powered vessels can’t be big. They must fit within a box that’s 6 feet long by 3 feet high and 3 feet wide, and must weigh less than 140 pounds. And there’s no dawdling. Teams are allowed a total of 20 minutes on the dock: 5 minutes for preparation and 15 minutes for the sub’s autonomous performance in the 16-foot depths of the pool’s competition section.
Here’s a look under the hood of the Seawolf. The triangular chassis was cut from high-density polyethylene, chosen because of its cost, rigidity and ease of machining.
The Seawolf’s main computer is a Lippert-AT CoolRunner4 PCI-04, which includes a 2.0GHz Pentium M processor and 1GB of RAM. The system uses a 20GB laptop hard drive for storage. It runs Windows XP.
The competition isn’t limited to teams from the United States. Four universities from Canada have entered, as have the Delhi College of Engineering and Japan’s Kyushu Institute of Technology. There’s also a team from Amador Valley High School in the San Francisco Bay Area.
This robot sub is the competitor for the Arise team from the University of Ottawa. (Arise stands for Advanced Robotics Innovations Society in Engineering.)
Other entrants include Duke University (its Scylla sub is seen here), Cornell University, the Massachusetts Institute of Technology and the University of Central Florida (the winner last year in the “best new design” category).
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