Automaton

Great robotics article this month in Spectrum. Senior editor Jean Kumagai and photo editor Randi Silberman traveled to a cactus-studded ranch in Mexico to find out how a research group is using an underwater robot to explore deep sinkholes.

The researchers, led by Bill Stone [above], best known for his daring cave diving expeditions, were field-testing DEPTHX, a 1.3‑metric-ton autonomous underwater machine that can draw 3D maps of its surroundings and also collect solid and liquid samples. (And as Kumagai notes in the article, the robot, encased in pebbly orange syntactic foam, "looks kind of like a giant tangerine.")

From the article:

There’s never been an aqueous robot quite like DEPTHX. Most autonomous underwater vehicles look the same, Stone says. “Some have fat midsections, some are more elongated, but they pretty much all look like weird torpedoes.” [...] “Their design is dictated by their mission: traveling in straight lines at relatively high speed to survey the ocean floor or gather bathymetry data,” he continues. But for exploring uncharted territory, that shape can get you in trouble. You can back yourself into a tight spot where you can’t turn around. [...] DEPTHX, by contrast, is designed not for high speed but for complicated maneuvering in unfamiliar environments. Hence its shape: a squashed sphere with no protruding parts to catch on things.

Read the full article, titled "Swimming to Europa," to learn how DEPTHX performed in Mexico. Oh, and don't miss the intrepid Spectrum correspondents' account of their encounter with Toilet Frog.

As I've mentioned before, I work for a company called Bluefin Robotics located in Cambridge, Massachusetts. I haven't really talked about our technology, but we just recently got a contract for the next generation of one of our coolest vehicles, and I really like talking about this one, so on to... the HAUV!

The Hovering Autonomous Underwater Vehicle started out as a joint project between Bluefin and MIT. It's a significant departure from our other vehicles, which are torpedo-shaped with propellers on the back. HAUV is more or less a box, not needing to be quite as hydrodynamic as its siblings, and as such has occasionally earned nicknames such as "Spongebob" in the Bluefin lab.

The HAUV is run by a main electronics housing (the brains) and a 1.5 kWh subsea battery that we make. It moves thanks to eight fancy hubless thrusters arranged to allow a full six degrees of freedom: X, Y, Z, roll, pitch, and yaw. To navigate it uses a Doppler Velocity Log (DVL), which provides the computer with velocity along the hull; an inertial measurement unit to measure orientation in space (or water!); a compass; and a GPS antenna to achieve a position lock when it's on the surface. Its payload is a Dual-frequency Identification Sonar (DIDSON), located on the front of the vehicle next to the DVL, which provides imagery of the ship hull that looks a lot like a blue ultrasound. The Soundmetrics website (linked above) shows what some of that imagery can look like.

HAUV communicates with an operator via a fiberoptic cable that runs between the vehicle and the ship, but the cable is there for transmission of sonar data, not for active control from the operator (though the operator can upload new sortie commands via the link). This is different from our other vehicles, which are not tethered in any way and instead communicate via acoustic link underwater or via Iridium satellite or an RF link on the surface (depending on distance from the ship).

So what is this all for? Hull inspection, basically. Plop this little guy in the water next to a ship and it can go to town taking images of the hull. If it sees something suspicious, the Navy or Coast Guard can send down a diver to check it out and dispose of it as appropriate. Port security is a big deal these days, so there could be a lot of work for the HAUV.

The United States Department of Defense has released its roadmap through 2032 (link to actual report at the bottom of the page; large PDF warning) for unmanned systems in the military. For this first time, this report includes not only unmanned ground vehicles (UGVs) but also unmanned aerial vehicles (UAVs) and unmanned underwater and surface vehicles (UUVs and USVs); previous reports had focused primarily on UGVs.

This is a very long but pretty fascinating read, particularly the president's budget through 2013 for funding in the three areas (section 2.4). It's really interesting to see that the UGVs like PackBots and Talons seem to be way ahead of other unmanned systems, with the R&D budget drastically decreasing over the next several years as the procurement budget skyrockets. The UAVs and UUVs, on the other hand, will still have a lot of R&D money pumped into them over the next several years. UAVs seem to be most popular with the highest overall procurement budget.

The report also goes into a nice explanation of the Dull/Dirty/Dangerous mantra that is so popular with American robotics development:

• For the dull, allows the ability to give operators normal mission cycles and crew rest.
• For the dirty, increases the probability of a successful mission and minimizes human exposure.
• For the dangerous, lowers the political and human cost if the mission is lost.

Lower downside risk and higher confidence in mission success are two strong motivators for continued expansion of unmanned systems across a broad spectrum of warfighting and peacetime missions.

There's also some good stuff on standardization and interoperability within the industries, including things like message format and processor speed. This will be good reading for the CTOs and budding entrepreneurs out there.

From Spectrum's February issue:

The small motorboat meanders through the Amazonian swamp. The water is a turbid brown, the jungle a thicket of twisted trees. A cricrió bird chirps from the treetops. The Brazilian researchers stop the boat to have a look around. Suddenly a noise breaks the calm. Buzzzzzzzzzzzzzzz.

Within seconds, an angry swarm of cabas, Amazon wasps with a powerful sting, envelops the boat and its unlucky occupants. To hear Ney Robinson Salvi dos Reis tell the story, you almost feel you're right there in the rain forest with him, fighting off the bellicose bugs.

“Jumping into the water is not a good idea,” Reis says. “There are crocodiles, snakes, piranhas, and a bloodsucking little fish called candiru that can enter your body orifices. So I covered my head and told the mateiro”—the Amazon native piloting the boat—“to get us out of there fast!”

For Reis, a robotics engineer at Petrobras, Brazil's state-controlled oil company, fleeing from wild wasps through treacherous waterways in excruciating heat and humidity is just part of the fun. He heads the robotics laboratory at Petrobras's underwater technology division in Rio de Janeiro. The company's main oil fields reside in deep waters off the Brazilian coast, so Reis's lab specializes in developing all sorts of Jules Vernian contraptions—a caterpillar-like robot to unclog underwater pipelines, a supersized hydraulic wrench that can work down to 2000 meters.

My friend Chris Murphy is a graduate student in the MIT/Woods Hole Oceanographic Institute joint program. Late last summer his group went on a research cruise to the Arctic Circle, so I asked him to tell me a little bit about the two underwater vehicles they used for their work. Read on for the interview and some of his pictures from the cruise!

Everyone lately is covering the thermally powered glider developed by Webb Research. Last week I attended the AUVSI/ONR Joint Review in Orlando, Florida, and I got to listen to someone from Webb talk a bit about their glider and how it works.

Gliders in general are a version of autonomous underwater vehicles (AUVs), but with one important distinction: they are buoyancy-driven, rather than using a propeller to generate thrust underwater. Gliders maintain the torpedo-like shape of traditional AUVs but typically have wings that provide an extra control surface. They use a variable buoyancy system to change how much they weigh in the water, allowing them to ascend or descend, and also modify weight distribution inside their bodies to change their pitch angle in the water.

For example, the Spray Glider we build at Bluefin (developed at the SIO) has a constant-volume pressure vessel filled with mineral oil that can be pumped into or out of a bladder that sits in a flooded section of the vehicle. When oil is pumped in, the bladder expands, and displaces water in that flooded section, increasing the vehicle's volume in the water and allowing it to ascend. Similarly, when it pumps the oil out of the bladder and back into the constant volume vessel, it permits water to fill the flooded section again, decreasing the vehicle's volume and causing it to sink. Internal battery packs mounted on tracks can move side to side (controlling the vehicle's roll) and forward and backward (letting it dive or climb), so combining the angle control with the varied buoyancy allows the vehicle to dive and climb in a sawtooth pattern through the water. With this sort of system, a glider can stay out for durations on the order of six months.

This technology is ideal for long-term missions. Because so little power is used compared to a propeller that is always spinning, a glider can stay out for months at a time on one battery charge rather than the tens of hours that a propelled vehicle can achieve on a single charge. Webb, however, has made a few modifications to their buoyancy system that may allow their new gliders to stay out for years.

Rather than relying on a battery-powered hydraulic system to pump mineral oil in and out of the bladder, the oil is normally contained in a plastic tube surrounded by a kind of wax chosen for its phase change properties. The wax is sensitive to the ocean temperature: at cold temperatures it contracts, but at warmer ocean temperatures it expands. The expansion increases the volume of the wax and squeezes the tube, which in turn squeezes mineral oil out into the rest of the vehicle's variable buoyancy system. This causes the vehicle to sink. When it reaches depth (and therefore a low water temperature), the wax contracts, which allows the oil to flow back into the tube out of the buoyancy system and the vehicle ascends.

So what Webb has done is eliminate the need for batteries to drive a hydraulic pump system. However, they still need batteries to run the onboard computer, sensors, communication system, and roll/pitch control system, meaning that these gliders aren't totally "green" yet. But they're on their way, and other glider researchers are following suit. Webb's recent demonstration -- the activity that generated all the press -- shows that this technology is ready to be out of the lab and into the ocean, so we can probably expect this system to become widespread pretty quickly. It will be interesting to see what other ocean-powered systems can be applied to these gliders to make them truly "green'.

Thermal glider image from webbresearch.com

The world's robot population has reached 4.49 million, and that number should nearly double by 2010 to 8.37 million. That's one automaton for every person in Austria, whatever that means! But we've written about that already: we put together these numbers based on data from the latest edition of World Robotics, a survey by the International Federation of Robotics released late last year.

Now we're looking again at this number-filled report and highlighting some of its best stuff. We want to know: What kinds of robots are out there? Where are they toiling around? And how fast are the silicon-brained things multiplying?

First, a recap: The World Robotics study divides robots in two main categories: industrial robots and service robots. The first category includes welding systems, assembly manipulators, silicon-wafer handlers—you know, that kind of heavy, expensive, several-degrees-of-freedom stuff. The second category is divided in two subcategories: professional service robots (things like bomb-disposal bots, surgical systems, milking robots) and personal service robots (vacuum cleaners, lawn mowers, all sorts of robot hobby kits and toys).

Below you'll find 10 statistics about the world's robotics market we thought you'd want to know. (All data from the World Robotics study except the world robot population figures -- see note [1] at the end.) The stats after the jump.