1. Lecture no. 4, 2005.05.09 ROV characteristics ROV types/classes
Work tasks for ROVs
Some work ROVs
NTNU’s Minerva vehicle
ROV simulators for engineering studies
ROV simulators for operator training
Review of underwater vehicle topics

2. ROV overview
ROV:
Remotely Operated Vehicle with umbilical connection to mother vessel
Umbilical is used for power transfer to the vehicle and for communication between it and its pilot

3. ROV types/classes A common classification is:
Low cost observation ROV (electric)
Small observation ROV (electric)
Large observation/light work ROV (electric)
Ultra-deep observation/sampling ROV (electric)
Medium light/medium work ROV (electro/hydraulic)
Large heavy work/large payload ROV (electro/hydraulic)
Ultra-deep heavy work/large payload ROV (electro/hydraulic)

4. Examples of ROVs Check organisational web sites
Check suppliers and operators websites:

5. NTNU ROV Minerva NTNU has bought an ROV for biological research
2 Dr. ing studies have been allocated to develop tools and procedures for scientific use of the ROV
For more info see the web site:

6. Minerva ROV

7. ROV operational goals Visual inspection
Inspection of underwater structures
Observation of ongoing work tasks on subsea structures
Biological observation
Different types of mechanical inspection
Non destructive testing
Mechanical work
Biological sampling, water column and bottom

8. Equation of motion for ROVs
6 degree of freedom (6DOF) model
No defined steady state motion as a baseline for development of motion equations
ROVs are usually asymmetrical up-down and fore-aft
As far as possible the ROVs are designed for port-starboard symmetry
See section 4.6 of lecture note for ROV motion equation

9. Hydrodynamic added mass/moment of inertia
6 x 6 matrix
Non-diagonal terms exists
Terms may have different values for positive and negative accelerations, especially for heave and pitch motion
Ideal fluid sink-source methods can be used
Motion decay tests can be used to find some terms
Generalized Planar Motion Mechanism tests can be used to find all terms
Simplified 2D crossections can be used to estimate some of the terms

10. Velocity dependent forces (drag and lift)
Non linear terms are important
Streamlining of bouyancy elements influence both drag and lift forces and moments
Motion decay tests can be used to find some drag terms
Generalized Planar Motion Mechanism tests can be used to find all terms

11. ROV umbilicals
Vessel motion and indusced motion at the upper end of the umbilical
Umbilical geometry resulting from depth varying current
Use of buoyancy 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

12. 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
Exercise no. 6 includes comparison of own calculations with model test results for MINERVA

13. Minerva 1:5 scale model test

14. Minerva 1:5 scale model test

15. Other forces Gravity and buoyancy forces and moments
Thruster forces and moments
Control forces from any additional control units
Umbilical forces
Environmental forces
Interaction forces from bottom and/or sea bed structures

16. STEALTH 3000 characteristics
Dimensions
Length: m
Breadth: m
Depth: m
7 horizontal and 3 vertical thrusters
Thruster pull and speed values:
1200kgf forward/aft, 5 knots forward, 3 knots reverse
500 kgf lateral, knots lateral
1000 kgf vertical, knots vertical

17. 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

18. 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

19. 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

20. 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.

21. Buzz group question no. 1:
List functional requirements for a ROV simulator to be used for accessability studies
(Activity not included in lecture)

22. Student responses 2004
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

23. Buzz group question no. 1 (cont), 2004:
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)

24. 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:
SH**2iL as their structure for simulators (Software-Hardware-Human-in-the-Loop)

25. Simulator design (cont.)
Check
for their modular simulator concept or

26. 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

27. 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

28. Oceaneering - ongoing work
MIMIC
Modular Integrated Man-Machine Interaction and Control
VSIS
Virtual Subsea Intervention Solution

29. FUTURE ROV OPERATIONS ”New” Concepts – ROV operations
AUV technology / AUV operations
WROV operations

30. FUTURE ROV OPERATIONS Work ROV operations
Optimisation of power efficiency
Absolute requirement for deeper water
Fully electric systems

31. FUTURE ROV OPERATIONS Work ROV operations
More efficient, Advanced intervention tasks requires:
Better vizualisation
Better planning
Better reporting systems
More training
Access verifications
Central control
How can this be acheived?

32. FUTURE ROV OPERATIONS Advanced intervention tasks 3D Navigation tools
3D based planning tool
Digital, visual ”online” reporting
Realistic Simulator training
Access verifications in Simulator during engineering/planning of operation
Central placed spesial control stations

33. FUTURE ROV OPERATIONS More efficient Work ROV operations MIMIC VSIS +
Modular Integrated Man-machine Interaction and Control +
VSIS
Virtual Subsea Intervention Solution

34. FUTURE ROV OPERATIONS More efficient Work ROV operations MIMIC
Realtime 3D positioning system for ROV operations
Built in, activity work plan
Generate work-status reports
Easy to construct and edit activity work plans
View active task functions

35. FUTURE ROV OPERATIONS
MIMIC

36. FUTURE ROV OPERATIONS
MIMIC

37. FUTURE ROV OPERATIONS
MIMIC

38. FUTURE ROV OPERATIONS
MIMIC

39. FUTURE ROV OPERATIONS
MIMIC

40. FUTURE ROV OPERATIONS
MIMIC

41. FUTURE ROV OPERATIONS VSIS Virtual Subsea Intervention Solution
ROV training simulator.
Central control room?

42. FUTURE ROV OPERATIONS
MIMIC

43. MIMIC / OST ROV simulator
MIMIC TEST ONB SCARABEO#5
Mimic – data flow chart
STAVANGER/STJØRDAL
SCARABEO 5
Telephone
HiPaP
MIMIC / OST ROV simulator
MIMIC
Sensors
DGPS
ROV System
3D Model
Database
3D Model
Database
Plan/ Report Database
ROV parameters
Ethernet
Video
Mimic coord.

44. Summary ROV
Observation platform to support topside operators performing complex subsea work tasks
Workhorse for installation and maintenance tasks
Tether management system is a must for ”workhorse” ROVs
ROV simulators are important for studies of accessability on subsea structures (engineering simulator)
ROV simulators are used for ROV pilot training