Accession Number : ADA308039

Title :   A Force Sensor System for the Robotuna Project.

Descriptive Note : Final rept.,

Corporate Author : MASSACHUSETTS INST OF TECH CAMBRIDGE DEPT OF OCEAN ENGINEERING

Personal Author(s) : Anderson, Pehr ; Barrett, David ; Triantafyllou, Michael

PDF Url : ADA308039

Report Date : APR 1996

Pagination or Media Count : 21

Abstract : 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. Additionally, a submarine requires a distance several times its length to turn, even at slow speeds, while fish can turn at full speed in a fraction of their length. Such limits are inherent in the propellers and place drastic restrictions on the range, speed, and application of current underwater vehicles. Fish represent one of nature's best solutions to the problems of underwater travel. Tuna cruise across the ocean at high speeds and many fish maneuver in and out of tight corners. The Robotuna project is an attempt to replicate these skills by emulating the form and motion of the tuna. The Robotuna project is an experiment to study the swimming efficiency of an underwater vehicle using fish-like propulsion. To measure this efficiency it is necessary to have an accurate array of force sensors inside the vehicle. This paper describes two iterations of the development of force sensors.

Descriptors :   *MANEUVERABILITY, *UNDERWATER VEHICLES, *DETECTORS, *EFFICIENCY, *REPLICAS, *MARINE PROPULSION, *TUNA, VELOCITY, WATER, HIGH VELOCITY, MOTION, ARRAYS, ACCURACY, LOW VELOCITY, SCALE, SELF OPERATION, TRAVEL, OCEANS, ITERATIONS, BARNACLES, MARINE PROPELLERS, FISHES, FORCE(MECHANICS), UNDERWATER, SWIMMING, SALVAGE, DRILLING MACHINES.

Subject Categories : Biology
      Submarine Engineering

Distribution Statement : APPROVED FOR PUBLIC RELEASE