Review of Autonomous Undersea Vehicle (AUV) Developments 
Video and time-lapse still cameras - Two video cameras and flood lights are mounted on the 
ROVER frame to monitor the operation of the benthic chambers and microprofiler. The cameras 
and flood lights are operated by the central controller, and the cameras’ video output is recorded 
on two Sony camcorders housed in the central-controller pressure case. The recordings 
provide information on the penetration of the benthic , \qmmE™ > END @ 
chambers and microprofiler into the sediment and the eat Phy 
operation of the stir bars. The topography of the sediment 
surface and the activity of animals within the transparent 
chambers and around the microprofiler are also monitored 
by the video system. A time-lapse still camera mounted 
on the ROVER frame and a remote strobe light mounted 
on the instrument rack are used to photograph the area in 
front of the ROVER during transits between measurement , 
sites. 
Current rotor and vane - Near-bottom current speed and 
direction are monitored using a Savonius rotor. The 
turning speed of the rotor is detected by an optical sensor. 
Current direction is determined by a vane, magnetically 
coupled to a servo-potentiometer. Outputs from the current 
rotor and vane are recorded by the central controller Figure 11. ROVER-Current Monitors 
during the entire deployment. The current rotor and vane are 
mounted on a small arm, which is raised and lowered by a lead screw (figure 11). 
Propulsion system - The ROVER is propelled across the sea floor by two, flexible, fiber- 
reinforced PVC tractor treads (50 cm wide by 3.6 m long). Each tread is independently driven to 
allow directional movement, which is determined by the central controller. Treads have molded 
external cleats in order to ensure traction in soft sediment. Each tread is driven by a 1/8-HP DC 
motor and a reduction gear train, housed in oil-compensated PVC housings. A load-bearing, 
low-friction, polyethylene pressure plate supports each tread. 
Central controller with data storage and central battery - The propulsion system, instrument 
assembly, cameras, current rotor and vane are all controlled by a central controller which 
consists of a microcontroller, interface electronics, electronic compass, tilt sensor, and video 
camcorders. The microcontroller (Onset, Model 7) has a real-time clock, a 64-MB hard drive 
and a 12-bit A/D converter to digitize sensor outputs. It is located in a titanium pressure 
cylinder, mounted on the mainframe of the ROVER. The electronic compass (KVH Industries, 
Model C100) allows the ROVER to maintain course during transits and turns. A tilt sensor 
(Lucas, Model Accustar II) provides tilt information to the controller to determine if the Rover is 
approaching a mound or slope. The distance traveled by the ROVER over the bottom is 
estimated by a Hall-effect sensor that detects the revolution of magnets embedded in the 
forward drive roller. Power for the ROVER and its instrumentation is provided by two alkaline 
battery packs (180 D-cells each), located in independent titanium pressure housings mounted 
on the ROVER frame beneath the central controller. These batteries have a total capacity of 
5000 watt-hours and are sufficient to power the ROVER in a typical deployment for up to 6 
months. 
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