This paper describes the computer controls and operator interface developed for a 20,000 foot depth rated Remotely Operated underwater Vehicle (ROV). The ROV has been successfully demonstrated on sea trials and recent operations including a record breaking 20,105 foot (6,128 m) dive. The length of the cable and duration of operations requires sophisticated controls and operator interface to successfully complete the mission.
Modern ROV's are capable of dives in excess of 15,000 ft (4,600 m). These inspection and salvage operations demand extended periods at depth to amortize the excessive surface-to-depth transition times. Once on the target site, a high degree of precise maneuvering is necessary to perform inspection and maintenance tasks. In addition to the demands these factors put on the vehicle systems, greater demands are placed on the operators themselves. To enable pilots and operators to maintain their efficiency, shorter shifts are required, thus requiring a greater staff of skilled operators.
The U.S. NAVY's new CURV III ROV, illustrates how the use of modern computer software can reduce the demands on operators, thus enabling them to work full shifts more productively.
The CURV III (Cable controlled Underwater Recovery Vehicle mark III) was designed and built for the U.S. NAVY Supervisor of Salvage. The system's prime mission description is the search, inspection, and recovery of equipment on the sea floor.
CURV III is rated in excess of 20,000 feet (6,100 m) and is tethered to a surface vessel with a 22,000 foot (6,700 m) Kevlar umbilical. The vehicle weighs 11,000 lbs (5,000 Kg) and is approximately 6' × 7' × 10' (182 × 213 × 304 cm). Photo 1 shows the CURV III vehicle held by its handling system.
Power for CURV is provided by two 40 HP (30 KW) Franklin Electric SEA-MERSIBLE motors driving a single 3000 psi (20 Mpa) hydraulic system. Two color, and two Silicon Intesifier Target (SIT) video cameras are used for piloting and inspection.
Nine INNER SPACE model 1002 turbine thrusters provide control over the vehicle's six degrees of motion. Three of the thrusters are vertically aligned to provide pitch, roll and vertical motion. Two horizontal, lateral thrusters provide yaw and lateral motion. Four horizontal thrusters canted 30 Deg from the fore/aft axis of the vehicle provide fore/aft motion with the option to supplement yaw and lateral motion.
Operation of the CURV vehicle is coordinated from a two station console. The PILOT display and control panel are tailored for flight control and monitoring. The CO-PILOT position provides auxiliary system monitoring and control for vehicle electric and hydraulic power, manipulators, sensors and actuators.
CURV III is a highly instrumented system, incorporating both external and internal sensors. External sensors are used to extract the maximum information about the vehicle's surroundings. External sensors include color, low-light video and still-frame cameras, twin sonars, pressure, temperature and altitude sensors.