May 5, 2013
I’m admittedly spoiled, jaded, snake bit. When I think of robotic systems I think of automated work cells, moving conveyor belts controlled by PLCs (programmable logic controllers) pick and place robots, SCARA (Selective Compliance Assembly Robot Arm) or Cartesian robotic systems. I have previously never thought about underwater robotic systems doing work hazardous or impossible for man. As it turns out, these underwater systems are remarkably useful and utilitarian. If we look at the various benefits, we see the following possible uses:
- Examination of “Texas Towers” in the Gulf of Mexico. (NOTE: Robotic systems were used extensively during the BP spill in the Gulf to estimate flow rate and devise a plan to make the necessary repairs.)
- Examination of underwater cable and electrical supplies.
- Examination of ship hulls both private and Federal.
- Deep water diving to investigate underwater surfaces for minerals.
- Investigation of sunken ships, the most notable—the Titanic.
- Search for new underwater species.
- Better definition of geology found underwater. Primarily pertaining to underwater investigations of earthquakes.
The slide show given below was originally presented by Ann R. Thryft, Senior Technical Editor, Materials & Assembly for Design News Daily. A great publication by the way. Let’s now take a look at those robotic systems presently operating and performing remarkable tasks.
The Serpent remotely operated vehicle (ROV) from Seaview Systems is designed for exploring very small-diameter pipelines. It can investigate conduits as small as 9 inches (23 cm) in diameter, and fit around bends with a radius as narrow as 27 inches (68.5 cm). Measuring 9 inch x 9 inch x 57 inch (23 cm x 23 cm x 145 cm) and weighing 70 lb (32 kg), the Serpent runs on two 300W brushless DC motors that give it a total forward thrust of 18 lb (8 kg). With a 0.5 inch (1.3 cm) diameter fiber-optic tether, it can explore as far as 6,000 ft (1,830 m) down a pipe or tunnel. A 360-degree pan/orbit/zoom color camera and two color cameras are included, along with two 70W high-intensity LEDs. The robot also has heading, pitch and roll, and depth sensors, as well as sonar. A fiber-optic telemetry system provides up to three video channels, four RS232 channels, and two RS485 channels. (Source: Seaview Systems)
Saab’s Seaeye Falcon DR remotely operated vehicle (ROV) is used in a wide variety of applications, including oil & gas exploration, scientific exploration and data-gathering and environmental monitoring. Its depth rating is 1,000 m (3,280 ft), and its maximum tether length is 1,100 m (3,608.9 ft) with a 14 mm (0.55 inch) diameter umbilical, although longer options can be achieved with custom umbilicals. It runs on a single-phase, universal auto-sensing, self-selecting input of 100-270V AC at 2.8 kW. The polypropylene chassis, measuring 635 mm x 600 mm x 1,055 mm (25 inch x 23.6 inch x 41.5 inch) is robust and lightweight for buoyancy and lack of corrosion. The robot’s launch weight is 100 kg (220.5 lb), payload is up to 15 kg (33 lb), and top speed is more than 3 knots. 6,400 lumens of LED lights with variable density can be tilted to vary intensity, linked to the video camera’s 180-degree tilting mechanism. Data and video are transmitted via F2 fiber optics. Powered by five magnetically coupled thruster units with a combined forward thrust of 50 kgf, the Seaeye Falcon DR has a 1:1 power to weight ratio. Standard sensors include auto depth and heading, pitch and roll, and compass. (Source: Saab)
The Seaview Systems long-distance remotely operated vehicle (LDROV) can travel up to 10,000 ft (3,000 m) on its 0.6 inch (1.5 cm) fiber-optic umbilical tether, and fit through a manhole only 20 inch (50.8 cm) in diameter. Measuring 17 inch x 18 inch x 41 inch (43 cm x 46 cm x 104 cm), the LDROV weighs 100 lb (45 kg). The top surface of its plastic frame has freewheeling wheels to make it easy for the robot to move smoothly and quickly through pipelines and tunnels. It’s driven by four 300W brushless DC motors that give the LDROV a total forward thrust of 72 lb (32.6 kgf). A 360-degree pan/orbit/zoom color camera and two 530-line color CCD cameras are included, as well as sonar, and sensors for heading, pitch and roll, and depth. A fiber-optic telemetry system provides up to three video channels, four RS232 channels, and two RS485 channels. (Source: Seaview Systems)
This second-generation jellyfish robot prototype, Cyro, built by engineers at Virginia Tech, is about the size of an adult man, weighing 170 lbs. Cyro’s 5 ft 7 inch diameter is a lot bigger than its little brother, the earlier RoboJelly, a tethered robot about the size of a man’s hand. Both can propel themselves through water and refuel themselves, but Cyro is autonomous, operating on a rechargeable nickel metal hydride battery. Both are part of a larger project to develop autonomous naval robots, funded by the Office of Naval Research and the US Naval Undersea Warfare Center. Cyro’s applications include making maps of the ocean’s floors, performing military surveillance, studying aquatic life, and monitoring environmental conditions and ocean currents. Jellyfish have a lower metabolic rate than other aquatic animals and consume less energy, and can withstand a wide range of temperatures, which is why the engineers chose them as energy-efficient biological models. The robots must last for months at a time at sea without human attention for maintenance or refueling. (Source: Virginia Tech)
DARPA is developing a robotic submarine to track human-staffed submarines, specifically quiet diesel electric subs. The Anti-Submarine Warfare (ASW) Continuous Trail Unmanned Vessel (ACTUV) is being designed to operate entirely without onboard human presence. Although it might seem that this could complicate the vessel’s design, the program expects to simplify sub design considerably by eliminating the systems that humans use and need. Those add a lot of constraints due to requirements for accessibility, crew support, and layout, as well as affecting the vehicle’s dynamic stability and reserve buoyancy. The autonomous ACTUV will operate for two or three months over thousands of kilometers while requiring only minimal supervision via remote control. This will require some unusual sensor technologies, as well as laser detectors, radar and sonar, for tracking what are some of the quietest submarines on the seas. Science Applications International Corporation (SAIC) will build and test the robotic sub. (Source: DARPA)
A prototype unmanned underwater vehicle (UUV), funded by DARPA and developed by a team of companies, will contribute to DARPA’s Anti-Submarine Warfare (ASW) surveillance effort. The UUV, called the Submarine Hold at RisK (SHARK), has demonstrated the ability to perform communications and sonar functions at great depths. Submarines will be detected using the Transformational Reliable Acoustic Path System (TRAPS), a fixed passive sonar node also operating on the deep seafloor. Next, SHARK will provide a mobile active sonar platform to track the subs. SHARK was built by Bluefin Robotics, a well-known manufacturer of autonomous underwater vehicles (AUVs), and member of the team headed by Applied Physical Systems (APS). Bluefin previously tested the UUV in February during two 4,450-m dives that totaled 11 hours. New capabilities that Bluefin has added to the specialized UUV include advanced pressure vessel design, a new power system, a high-powered acoustics transducer system, an extended operational depth rating, and a transportable docking head launch and recovery system. Next steps are to completely integrate the deep-sea sonar function into SHARK. Eventually, a second vehicle will be built with integrated sonar for networked operations. TRAPS and SHARK are both part of DARPA’s Distributed Agile Submarine Hunting (DASH) program. (Source: DARPA)
iRobot, maker of housecleaning and bomb-sniffing robots, also makes autonomous underwater vehicles (AUVs) for scientific research and offshore oil & gas data collection. After the 2010 BP oil spill in the Gulf of Mexico, iRobot sent in its 1KA Seaglider robot to monitor underwater conditions, including the presence of oil, at depths as low as 1,000 m (3,280 ft). The autonomous long-range high-endurance robot is designed for missions that range over thousands of miles and last many months. It’s designed for persistent surveillance, marine environmental monitoring, current profiling, seep detection, and data gathering for physical, chemical, and biological oceanography. The Seaglider is 1.8 m to 2 m (5.9 ft to 6.5 ft) long, depending on configuration, has a diameter of 30 cm (11.8 inch) and a wingspan of 1 m (3.3 ft), and weighs 52 kg (114.6 lb). It can be configured to operate at depths of 50 m to 1,000 m (164 ft to 3,280 ft), has a maximum travel range of 4,600 km (2,858.3 miles), and typical speed is 1/2 knot. It uses lithium sulfuric chloride batteries that last up to 10 months. Guidance systems include GPS, an Iridium modem, a 3-axis compass, an acoustic transponder, and an altimeter. The choice of sensors may include a truly enormous variety. (Source: iRobot)
An autonomous robotic vehicle for exploring lakes on other planets has been developed by researchers in the University of Arizona’s department of electrical and computer engineering. Something like a nautical version of a planetary rover, the lake lander, also called the Tucson Explorer II (TEX II), could be used to investigate the liquid hydrocarbon lakes on Titan, Saturn’s largest moon. Although it will be a while before TEX II goes on a mission to Titan, it can be used on Earth to clean up littoral munitions dumps and mines, as well as harbor surveillance, environmental research, and search and rescue operations in oceans, lakes, and hazardous environments. Controllable via an Internet connection, TEX II has cameras and sonar operational up to 100 m. Its catamaran design provides stability, with two 6-ft long fortified Styrofoam hulls about 5 ft apart. The Styrofoam lets the lake lander withstand hull damage while maintaining buoyancy of its 100-lb weight and 150-lb payload. The hulls’ shallow draft also keeps water perturbation low, for better telemetry of the onboard sensors measuring surface and subsurface liquid conditions. TEX II can also move forward or backward depending on the rotational direction of the electric motors that power its air propellers, mounted at the back of each hull. (Source: University of Arizona)
The Nereus hybrid remotely operated vehicle (HROV) has been designed to go into the deepest ocean trenches on the planet, where it must withstand extraordinary pressures. Instead of glass and steel, it’s made with an aluminum frame and a ceramic housing that protects electronics from that pressure, as well as gives it buoyancy. Nereus can work either on a tether, like an ROV, or it can operate autonomously as an autonomous underwater vehicle (AUV). The two modes are for accomplishing different tasks. In AUV mode, it can map the seafloor and survey large areas using its LED lights, cameras and sonar, traveling at speeds up to 3 knots. Once the robot locates an object or region of interest, it can be brought back to the support ship, tethered with a fiber-optic cable, and sent back to the area of interest. The cable is then used to receive commands and transmit video while it conducts experiments or collects samples with its manipulator arm. Nereus operates on rechargeable lithium-ion battery packs, each containing about 2,000 batteries like the ones used for laptop computers. It weighs 2,800 kg (6,172.9 lb) and has a payload of 25 kg (55 lb).
(Source: Advanced Imaging and Visualization Laboratory, Woods Hole Oceanographic Institution)
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