HERCULES SCIENCE SENSORS AND CAPABILITIES

 

Jim Newman  2 OCT 2003

 

 

System rated depth: 3000 meters

Vehicle air weight: approx 5200 lbs (2340 kg)

Hydraulic power: 20 HP, 3000 psi max (1000 and 2000 psi pressures available)

 

Available switched electrical power:

  • 120 VAC, 60 Hz, up to 1000 w.
  • 24 VDC, up to 3A
  • 12 VDC, up to 6A

 

Imaging

  • one High Definition (1035i) color zoom camera, on pan/tilt/extend platform
  • bubblecam, operator-aimable and zoomable, mounted on brow
  • utility cameras, some with LED illumination
  • up to four NTSC video channels (in addition to the HD)
  • recording on DVCAM format or leased HD
  • all signals in control van are SDI digital format
  • Pixelfly digital still cameras (stereo pair, one color, one monochrome)

 

Lighting:

  • up to four 250 W incandescents (DSPL Deep Multi-Sea Lite)
  • Two 400W HMI ballasted (DSPL)
  • Two Ocean Imaging 130 w-sec strobes

 

Sensors

  • Paroscientific 8B4000-I pressure/depth sensor
  • Falmouth Scientific Micro-2 CTD
  • Aanderaa Optode oxygen sensor
  • Benthos PSA-916D altimeter
  • RDI Doppler Velocity Log
  • Heading and attitude reference: Crossbow AVRS-400

 

Sampling

  • Kraft Predator force-reflecting manipulator arm, 7DOF
  • ISE manipulator arm, 7DOF
  • Tool Drawer, hydraulically actuated
  • Sample Drawer, hydraulically actuated
  • Suction pump (two); XXXX gal/min, operator-adjustable
  • Jetting pump (two); XXXX psi, XXXX gal/min, operator-adjustable
  • Other hydraulic functions can be configured to user requirements

 

Navigation

  • USBL (ship-based) acoustic Navigation to at least 500 m
  • HYPack integrated navigation software

 

Payload for samples: Approx. 100 lbs/ 42 kg (in water)

 

 

 

 

 

 

HERCULES Technical summary


While HERCULES is specifically intended to excavate ancient shipwreck sites, for the most part it is a fairly conventional "work-class" ROV (remotely operated vehicle). It is made up of an aluminum frame holding most of the components, supported when the vehicle is in the water by a flotation package of "syntactic foam", a composite material that has a specific gravity of about 0.47 and can handle the pressure the vehicle will see at its rated depth of 3000 meters (almost 5000 psi).  With the flotation block the vehicle can be trimmed to neutral bouyancy, so thrusters can control its vertical position.

HERCULES operates in concert with another vehicle, ARGUS. ARGUS has no bouyancy module, and is intentionally much heavier than water.  It dangles at the end of the main cable from the ship.  A relatively short neutrally buoyant tether connects HERCULES to ARGUS.  This configuration allows ARGUS to decouple ship and cable motions from HERCULES.  ARGUS also acts as a lighting and video platform in its own right, and is equipped with High Definition video camera identical to that on HERCULES.  ARGUS carries three HMI lights, with power totalling 2000 watts.


The vehicles operates on the end of a 4200 meter long steel-armored cable, which brings three phase power from the ship at 2700 VAC. The hydraulic power unit's 20 HP motor operates at this voltage, but all other electrical loads are run on 120 VAC from a single-phase step-down transformer.

The hydraulic pump drives thrusters, manipulator arms, and the pan/tilt for the cameras, as well as pumps and other hydraulic functions specific to the excavation tools.  Those tools include jetting and suction pumps to carefully stir up and suck away the sediment overlaying sites of interest.

Most of Hercules' functions, including the thrusters, are controlled by an on-board PC104 computer. Two rackmount computers topside provide interfaces to users and to other shipboard systems.  A joystick box is the primary interface for the pilot who drives the vehicle.

All communications with the vehicle are over the three fiber optic elements in the cable that connects the vehicle to the ship. A primary optical multiplexor handles most digital data and standard-resolution video.  High definition video and images from a stereo pair of electronic still cameras are sent on dedicated optical wavelengths. Most of the subsea electronics are housed in a 10" ID cylindrical titanium pressure housing.