Current robotic sailing relies on sensing wind direction and moving the sails to a position that ... more Current robotic sailing relies on sensing wind direction and moving the sails to a position that is appropriate for that relative wind angle. The research to date shows that a correctly tuned sail in the classic wing shape is essential for maximum speed over water. This paper relates research on sensors used to determine when sail trim is incorrect. With improper sail trim, the sail luffs. This luffing produces turbulence which reduces the efficiency of the sail. By instrumenting the sail with sensors to detect when sails begin to luff, the robot can determine when the sail is improperly trimmed and, potentially, take corrective action.
Conventional tagging methods using plastic streamer tags have been the most widely used tool for ... more Conventional tagging methods using plastic streamer tags have been the most widely used tool for elucidating fish movements in the last half century. With a very high failure rate1, these methods for fish tagging and tracking are unreliable and prohibitively expensive for tracking global fish populations. Under the current method, fishermen are required to remember the time and location of the catch, the size of the fish, and the weight of the fish. In order to report a tagged fish, a fisherman cuts off and keeps the tag from the fish. Later, the fisherman must go back and submit the form using the information they can remember from earlier in the day or even several days ago. The long delay and relative difficulty between catch and data entry creates a barrier to data collection. The Olin College of Engineering Intelligent Vehicles Laboratory, in partnership with The Large Pelagics Research Center, has been developing a new, automated method for data reporting from fish tags.
Perimeter patrol enhances the utility of autonomous surface vehicles (ASVs) by enabling many secu... more Perimeter patrol enhances the utility of autonomous surface vehicles (ASVs) by enabling many security and scientific missions, including harbor protection, water sampling, and geological survey. We present a novel approach to perimeter patrol that uses only two sensors: commercial off-the-shelf available marine radar and the heading information from a GPS. Our algorithm performs computer vision morphological operations on the radar image to find a suitable path around shore and choose an appropriate next waypoint. Our method has proved robust to a variety of field conditions, allowing us to demonstrate the autonomous navigation of a 3.5 km perimeter lake.
Proceedings of Symposium on Autonomous Underwater Vehicle Technology
Page 1. The Optimal Control of a Flexible Hull Robotic Undersea Vehicle Propelled by an Oscillati... more Page 1. The Optimal Control of a Flexible Hull Robotic Undersea Vehicle Propelled by an Oscillating Foil David Barrett Mark Grosenbaugh Michael Triantafyllou Dept. of Ocean Engineering 77 Mass Ave. Rm 48-015 Cambridge, Ma. 02139 Dept. ...
Thrust-producing harmonically oscillating foils are studied through force and power measurements,... more Thrust-producing harmonically oscillating foils are studied through force and power measurements, as well as visualization data, to classify the principal characteristics of the flow around and in the wake of the foil. Visualization data are obtained using digital particle image velocimetry at Reynolds number 1100, and force and power data are measured at Reynolds number 40 000. The experimental results are compared with theoretical predictions of linear and nonlinear inviscid theory and it is found that agreement between theory and experiment is good over a certain parametric range, when the wake consists of an array of alternating vortices and either very weak or no leading-edge vortices form. High propulsive efficiency, as high as 87%, is measured experimentally under conditions of optimal wake formation. Visualization results elucidate the basic mechanisms involved and show that conditions of high efficiency are associated with the formation on alternating sides of the foil of a...
Underwater vehicles have many uses in civilian as well as military marine operations. Their appli... more Underwater vehicles have many uses in civilian as well as military marine operations. Their applications range from maintenance and inspection on oil rigs to underwater salvage operations, and from scraping barnacles off the hulls of ships to searching a hostile bay for mines. For such vehicles to carry out their tasks it is advantageous to have high propulsive efficiencies. Efficiency for an underwater vehicle is measured by recording the amount of energy required to pull the vehicle through the water at a certain velocity and comparing that to the energy which the vehicle must expend to propel itself at the same velocity. Propellers are the primary conventional mechanism for water-based propulsion. The efficiency of a propeller scales up with specific load. This means that while a propeller works well on a vehicle with large available diameter, like a submarine, it has a rather limited efficiency for smaller autonomous vehicles where propellers must fit in cramped spaces. Addition...
Current robotic sailing relies on sensing wind direction and moving the sails to a position that ... more Current robotic sailing relies on sensing wind direction and moving the sails to a position that is appropriate for that relative wind angle. The research to date shows that a correctly tuned sail in the classic wing shape is essential for maximum speed over water. This paper relates research on sensors used to determine when sail trim is incorrect. With improper sail trim, the sail luffs. This luffing produces turbulence which reduces the efficiency of the sail. By instrumenting the sail with sensors to detect when sails begin to luff, the robot can determine when the sail is improperly trimmed and, potentially, take corrective action.
Conventional tagging methods using plastic streamer tags have been the most widely used tool for ... more Conventional tagging methods using plastic streamer tags have been the most widely used tool for elucidating fish movements in the last half century. With a very high failure rate1, these methods for fish tagging and tracking are unreliable and prohibitively expensive for tracking global fish populations. Under the current method, fishermen are required to remember the time and location of the catch, the size of the fish, and the weight of the fish. In order to report a tagged fish, a fisherman cuts off and keeps the tag from the fish. Later, the fisherman must go back and submit the form using the information they can remember from earlier in the day or even several days ago. The long delay and relative difficulty between catch and data entry creates a barrier to data collection. The Olin College of Engineering Intelligent Vehicles Laboratory, in partnership with The Large Pelagics Research Center, has been developing a new, automated method for data reporting from fish tags.
Perimeter patrol enhances the utility of autonomous surface vehicles (ASVs) by enabling many secu... more Perimeter patrol enhances the utility of autonomous surface vehicles (ASVs) by enabling many security and scientific missions, including harbor protection, water sampling, and geological survey. We present a novel approach to perimeter patrol that uses only two sensors: commercial off-the-shelf available marine radar and the heading information from a GPS. Our algorithm performs computer vision morphological operations on the radar image to find a suitable path around shore and choose an appropriate next waypoint. Our method has proved robust to a variety of field conditions, allowing us to demonstrate the autonomous navigation of a 3.5 km perimeter lake.
Proceedings of Symposium on Autonomous Underwater Vehicle Technology
Page 1. The Optimal Control of a Flexible Hull Robotic Undersea Vehicle Propelled by an Oscillati... more Page 1. The Optimal Control of a Flexible Hull Robotic Undersea Vehicle Propelled by an Oscillating Foil David Barrett Mark Grosenbaugh Michael Triantafyllou Dept. of Ocean Engineering 77 Mass Ave. Rm 48-015 Cambridge, Ma. 02139 Dept. ...
Thrust-producing harmonically oscillating foils are studied through force and power measurements,... more Thrust-producing harmonically oscillating foils are studied through force and power measurements, as well as visualization data, to classify the principal characteristics of the flow around and in the wake of the foil. Visualization data are obtained using digital particle image velocimetry at Reynolds number 1100, and force and power data are measured at Reynolds number 40 000. The experimental results are compared with theoretical predictions of linear and nonlinear inviscid theory and it is found that agreement between theory and experiment is good over a certain parametric range, when the wake consists of an array of alternating vortices and either very weak or no leading-edge vortices form. High propulsive efficiency, as high as 87%, is measured experimentally under conditions of optimal wake formation. Visualization results elucidate the basic mechanisms involved and show that conditions of high efficiency are associated with the formation on alternating sides of the foil of a...
Underwater vehicles have many uses in civilian as well as military marine operations. Their appli... more Underwater vehicles have many uses in civilian as well as military marine operations. Their applications range from maintenance and inspection on oil rigs to underwater salvage operations, and from scraping barnacles off the hulls of ships to searching a hostile bay for mines. For such vehicles to carry out their tasks it is advantageous to have high propulsive efficiencies. Efficiency for an underwater vehicle is measured by recording the amount of energy required to pull the vehicle through the water at a certain velocity and comparing that to the energy which the vehicle must expend to propel itself at the same velocity. Propellers are the primary conventional mechanism for water-based propulsion. The efficiency of a propeller scales up with specific load. This means that while a propeller works well on a vehicle with large available diameter, like a submarine, it has a rather limited efficiency for smaller autonomous vehicles where propellers must fit in cramped spaces. Addition...
Uploads
Papers by David Barrett