TMR4225 Marine Operations, 2004.03.11

1
TMR4225 Marine Operations, 2004.03.11

• ROV systems
• Umbilical
• Control system
• MINERVA drag characteristics
• STEALTH hydrodynamic characteristics
• ROV simulators
• Future challenges

2
ROV umbilicals

• Vessel motion and induced motion at upper end of
  umbilical
• Umbilical geometry resulting from depth varying
  current
• Use of buoyance and weight elements to obtain a
  S-form to reduce umbilical forces on the ROV
• Induced transverse vibrations of umbilical
• Forces and motions at lower end of umbilical

3
MINERVA tests

• Drag tests,varying speed
• Drag test, varying angle of attack
• Full scale tests
• Use of vehicle to generate input to parametric
  identification of mathematical model
  characteristics
• A possible project involving NTNU, Marine
  Cybernetics and Sperre?
• Exercise no.5 includes comparison of own
  calculations with model test results for MINERVA

4
STEALTH 3000 characteristics

• Dimensions
• Length 3.2 m
• Breadth 1.9 m
• Depth 1.9 m
• 7 horizontal and 3 vertical thrusters
• Thruster pull and speed values
• 1200kgf forward/aft, 5 knots forward, 3 knots
  reverse
• 500 kgf lateral, 2 knots lateral
• 1000 kgf vertical, 2.4 knots vertical

5
Hydrodynamic analysis of STEALTH

• MSc thesis on Manoeuvrability for ROV in a deep
  water tie-in operation
• Simplified geometries used when estimating added
  mass coefficients based on work by Faltinsen and
  Øritsland for various shapes of rectangular
  bodies
• Quadratic damping coefficients used, corrections
  made for rounding of corners based on Hoerner
  curves
• Maximum speed as a function of heading angle has
  been calculated using simplified thruster model

6
ROV operational challenges

• Surface vessel motion
• Crane tip motion
• Umbilical geometry and forces
• ROV hydrodynamic characteristics
• Influence of sea bottom
• Interference from subsea structures
• ROV control systems

7
ROV simulator systems requirements

• System requirements give DESIGN IMPLICATIONS with
  respect to
• Simulation software
• Computer hardware architecture
• Mechanical packaging
• See article by Smallwood et. al. for more
  information
• A New Remotely Operated Underwater Vehicle for
  Dynamics and Control Research

8
System requirement - Example

• Simulate a variety of ROV design configurations
  for both military and commercial mission
  applications
• DESIGN IMPLICATIONS for simulation software
• Sensor databases must include a wide range of
  underwater objects
• Modular model for ROV hydrodynamics
• Standard protocols for information exchange
  between modules
• DESIGN IMPLICATIONS for mechanical packaging
• System must be reconfigurable to replicate a wide
  range of control/operator console layouts.

9
Buzz group question no. 1

• List functional requirements for a ROV simulator
  to be used for accessability studies
• Student responses
• Easy integration of different kinds of underwater
  structures
• Easy implementation of different ROVs
• Easy implementation of different types of sensors
• Realistic model of umbilical
• Catalogue of error modes and related what if
  statements
• Ability to simulate realistic environmental
  conditions, such as reduced visability and
  varying sonar conditions

10
Buzz group question no. 1 (cont)

• Realistic simulation of different navigation
  systems
• Obstacle recognition and handling
• Easy input interface for parametres related to
  ROV geometry, environment, navigation systems and
  different work tools
• Realistic model for calculation of ROV motion
• Good interface for presentation of ROV position
  and motion, including available control forces
  (Graphical User Interface, GUI)

11
Simulator design

• A modular design will make it easy to change
  modules for different subsystems of a ROV, subsea
  structures etc
• The simulator should allow both real time and
  fast time simulation
• High Level Architecture (HLA) is used for defence
  simulators to allow different modules to
  communicate through predefined protocols
• Marine Cybernetics uses
• SH2iL as their structure for simulators
  (Software-Hardware-Human-in-the-Loop)

12
Simulator design (cont.)

• Check
• http//www.marinecybernetics.com
• for their modular simulator concept
• or
• http//www.generalrobotics.co.uk/rovsimrecent.htm
• http//rovolution.co.uk/GRLMATIS.htm

13
Necessary improvements for advanced ROV operations

• 3D navigational tools
• 3D based planning tools
• Digital, visual online reporting
• Realistic simulator training for pilots
• Access verification using simulator during the
  engineering phase of a subsea operation involving
  ROVs
• Central placed special control room

14
Challenges for future ROV operations

• Better visualization for pilot situational
  awareness
• Better planning of operations, for instance
  through use of simulator in the engineering
  design and development of operational procedures
• Better reporting system, including automatic
  functions to reduce the workload of the ROV pilot
• Closer co-operation between ROV pilot and subsea
  system experts in a central on shore operations
  control centre

15
Oceaneering - ongoing work

• MIMIC
• Modular Integrated Man-Machine Interaction and
  Control
• VSIS
• Virtual Subsea Intervention Solution