Rock Coring Technology on the Juan de Fuca

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Rock Coring Technology on the Juan de Fuca
Plate with the MBARI ROV Tiburon
Image by D. Au
Presented by K.A. Salamy M.R. Chaffey, J.
Erickson, D. Au, T.C. OReilly, D. Stakes
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Topics

• Brief history of Multiple-barrel Coring System
  
• (MCS) on underwater science platforms

• Recent Adaptation of the MCS to the ROV
• Tiburon
  - Project
  Requirements
• - System Design Modifications

• MBARI Summer 2000 Coring Highlights
  - Juan de Fuca Plate

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ALVIN Submersible (1991, 1996)
ROV ROPOS (1998)
ROV Ventana (1992-1999)
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Project Purpose

• Adapt the MCS to Tiburon for marine geological
  sampling

- Increased depth capabilities - 4000 meters


- Wider geographical sampling coverage
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Direct Transfer of Existing Technology

• Minimum changes to Ventana design

• Main modifications/additions to
• - MCS control system
• - Software Architecture (real-time feedback)
• - New toolsled frame

• Summer 2000 hard deadline date

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Functional Requirements

• 4000-meter MCS operational depth

• Tiburon MCS performance must equal
• existing design
• - Sufficient power to core
• - Maintain position while coring
  
• - Similar coring rates (0.5m / hr)
  
• - Horizontally-level cores

• Explosive cutter software and hardware
• must operate safely and reliably

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Design Issues

• Power for coring on Tiburon - 15kW
• - Hydraulic power
• - Thrust for Weight-On-Bit
• - Station-keeping abilities

• Re-use versus Redesign of existing system
• - Sensing and control
• - Explosive cutter circuit
• - Software architecture

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System Design Requirements

• Total power to operate MCS (lt 5.3 kW)
• Minimum drillstring stall torque 130 Nm
• RPM variable from 0 to /- 400 RPM
• Provide 220 lbs Weight-On-Bit
• Use standard Tiburon toolsled frame

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Ventana Performance
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Estimated Tiburon Performance
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Weight-On-Bit Analysis
138 lbs.
270 lbs.
270 lbs.
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Tiburon Power Consumption Values
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Image by D. Au
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Data-CONcentrator (DCON) for Sensing and Control

• Versatile hardware development
• - Multiple 2A current digital outputs for
• hydraulic valve control
• - Analog inputs for reading sensors
• - Analog outputs for hydraulic servo valves
• - Digital outputs for controlling cutter circuit
• - Digital inputs for monitoring cutter status
• - Ground fault, humidity and water alarms

• Efficient software development

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Image by D. Au
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Resulting Tiburon MCS Design
Image by J. Erickson
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Explosive Cutter Requirements

• Shears drill string when
• Commanded by pilot and below 150 meters
• or
• System armed and power lost for one hour and
  below 150 meters

• Does NOT fire otherwise!

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Image by D. Au
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Explosive Cutter Firing Sequence
Pilot commands fire
Power plug inserted on deck
Pressure switch closes
Pilot commands arm
FAST FIRE
POWER PLUG
150 METERS
ARMED
Power fail fire
DELAYED FIRE
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Disarm button pushed or pressure switch opens
Disarm button pushed or pressure switch opens
Arm button pushed and password entered
Disarm button pushed or pressure switch opens
Delayed- firing
DCON power ON
Fast-fire button pushed and password entered
DCON power OFF
DCON power OFF
Fast-fire button pushed and password entered
1 hour elapsed
15 seconds elapsed
Explosive Cutter State Diagram
Fired
Allowable if cutter mistakenly believes IBC
power is OFF
Software-initiated transition
Hardware-initiated transition
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Application Software Requirements

• Graphical user interface (GUI)
• - Display and control MCS state

• Accept and process user commands

• Sample and distribute sensor telemetry

• Sense and report DCON events

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Western Flyer
optical fiber
serial lines
Sonar DCON
Main vehicle computer
Camera DCON
MCS DCON
Tiburon
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DCON micro- processor
GUI workstation
DataManager items
Main vehicle computer
alarms, events
Main task
sensor telemetry
Sampler
DCON
196 CPU
Command monitor
commands
DCON application components
- Object Oriented Techniques provide rapid
software development that is robust, efficient
and maintainable.
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DCON micro- processor
GUI workstation
DataManager items
Main vehicle computer
alarms, events
Main task
sensor telemetry
Sampler
DCON
196 CPU
Command monitor
command
commands
telemetry

• User pushes Drill button on GUI to begin coring
  GUI writes DataManager commands item to ON

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DCON micro- processor
GUI workstation
DataManager items
Main vehicle computer
alarms, events
Main task
sensor telemetry
Sampler
DCON
196 CPU
Command monitor
command
commands
telemetry

• Command monitor task on main vehicle computer
  detects change in commands DataManager item
• Reads value, checks for valid requested state

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DCON micro- processor
GUI workstation
DataManager items
Main vehicle computer
alarms, events
Main task
serial
sensor telemetry
Sampler
DCON
196 CPU
Command monitor
command
commands
telemetry

• Command monitor task writes switch on serial
  command to hydraulic valve switch card on DCON

• Switch closes

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DCON micro- processor
GUI workstation
DataManager items
Main vehicle computer
alarms, events
Main task
serial
sensor telemetry
Sampler
DCON
196 CPU
Command monitor
command
commands
telemetry

• Sampler task periodically reads card state via
  serial line

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DCON micro- processor
GUI workstation
DataManager items
Main vehicle computer
alarms, events
Main task
serial
sensor telemetry
Sampler
DCON
196 CPU
Command monitor
command
commands
telemetry

• Sampler task updates DataManager item to reflect
  new switch state

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DCON micro- processor
GUI workstation
DataManager items
Main vehicle computer
alarms, events
Main task
serial
sensor telemetry
Sampler
DCON
196 CPU
Command monitor
command
commands
telemetry

• GUI detects changed value of switch state item,
  updates display

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DCON micro- processor
GUI workstation
DataManager items
Main vehicle computer
alarms, events
Main task
serial
sensor telemetry
Sampler
DCON
196 CPU
Command monitor
command
commands
telemetry

• Main task monitors the DCON for unsolicited
  events (e.g., alarms and events), propagates the
  events through DataManager, and updates the GUI
  display

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CLEFT DRILL CORE SAMPLE LOCATIONS
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Mendocino Ridge Core
cm
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Science Benefits

• MCS used on 7 geology dives
• - 11 cores acquired
• - Similar coring rates
• - High resolution sampling

• All cores deeper than 2000 meters.
  - Deepest at 3,160 meters.

• Coreholes horizontally-level
• - Future instrument emplacements.

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Additional Design Benefits

• Fast integration of MCS on Tiburon
  - 1 hour toolsled change-out

• Consistent use of proven applications
• - Interchangeable toolsleds
• - Modular DCON-based electrical
  architecture
• - Application framework software
  architecture

• Efficient implementation of new systems
  - Ensures pilot familiarity (command /
  controls) - Minimizes pilot training
  time