TMR4225 Marine Operations, 2006.02.16 Lecture content: AUV hydrodynamics Mathematical model – 6 DOF HUGIN navigation and control system
HUGIN history AUV demo (1992-3) HUGIN I & II (1995-6) Diameter: 0.766 m Length: 3.62/4.29 m Displacement: 1.00 m**3 HUGIN I & II (1995-6) Diameter: 0.80 m Length: 4.8 m Displacement: 1.25 m**3 HUGIN 3000C&C and 3000CG (1999-2003) Diameter: 1.00 m Length: 5.3 m Displacement: 2.43 m**3
Hugin UUV
Actual HUGIN problems Roll stabilization of HUGIN 1000 Low metacentric height 4 independent rudders PI type regulator with low gain, decoupled from other regulators (heave – pitch – depth, sway – yaw, surge) Task: Keep roll angle small ( -> 0) by active control of the four independent rudders Reduce the need for thrusters and power consumption for these types of tasks Docking on a subsea installation Guideposts Active docking devices on subsea structure (robotic arm as on space shuttle for capture of satelittes)
Principal Investigator AUV-LAB MIT Odyssey IV Principal Investigator C. Chryssostomidis F. Hover Design Team R. Damus S. Desset J. Morash V. Polidoro
Russian proposal for Arctic oil and gas production No existing infrastructure Harsh environment (ice and low temperatures) Using subsea vehicles for drilling and prosuction
A future Arctic oil and gas scenario
Underwater Drilling System Submarine Drilling Vessel Bottom Template
Possible Shtokman solution? SDV TRUV SSV ROV BT TLP Container TMS 2…3 km
% probability of sea ice (April) in Barents Sea (Orheim, Houston, 2005) Shtokman
Example: 3 days track for iceberg (marking per 3 hours) (Orheim, Houston, March 2005)
Phases of an AUV/UUV mission Pre launch Launching Penetration of wave surface (splash zone) Transit to work space Entering work space, homing in on work task Completing work task Leaving work space Transit to surface/Moving to next work space Penetration of surface Hook-up, lifting, securing on deck
Group work no. 1 – Student feedback Launching Launching arrangement; A-Frame, crane etc Readiness for operation, eg. various equipment on board All openings on the hull surface must be closed (watertightness)
Group work no. 1 – Student feedback Penetration of splash zone Impact loads Hydro-elasticity Relative motion; phase, amplitude, frequency Change of parametres from air to water (buoyancy, eigenfrequency, etc.) Wire tensions
Group work no. 1 – Student feedback Transit to work space Navigation/control system (current/flow/(diving)), DP Buoyancy during transit ( different layers of salinity in the sea) Resistance/propulsion/endurance/power supply Material/hullform ( the vehicle has to withstand high external pressure)
Group work no. 1 – Student feedback Entering work space, homing in on work task No group looked at this activity
Group work no. 1 – Student feedback Completing work task Battery capacity Check if mission is completed Check the current conditions Safe manoeuvring to avoid collisions, damage of propellers Interaction between thrusters
Group work no. 1 – Student feedback Leaving work space No group looked at this activity
Group work no. 1 – Student feedback Transit to surface/Moving to next work place Changing buoyancy (pressure/gravity) Resistance forces (transit between workfields) Current forces Wave influence near surface Subsea navigation, track control, specification of way points
Group work no. 1 – Student feedback Penetration of surface Movements induced by: Waves Current (viscous forces) Buoyancy/gravity Reaching the surface -> change of: Wetted surface (viscous) Buoyancy (volume) According to the sea state, we can have a very unstable system
Group work no. 1 – Student feedback Hook-up Sea state; ship motion, AUV motion Effect of wind in the crane Centre of gravity of AUV Lifting Splash zone, wind, safety distance Securing on deck Safe bed Transport on deck to storage container
Web sites: http://www.ausi.org/research/research.html http://www.freesub.soton.ac.uk http://www.cs.nps.navy.mil/research/auv/auv_links.htm http://auvlab.mit.edu/research/index.html
R&D program on Underwater navigation Develop navigation systems to be used for missions with long period of submerged vehicle Error robust systems, optimal use of working sensors Develop mathematical models and algoritms for new sensors with extreme precision In water testing of new sensors and mathematical models Project is based on experience and solutions used for the HUGIN family of vechicles
TMR4225 Marine Operations, 2006.02.16 Sum up the 3 most important learning outcomes of todays lecture Have your expectations been fulfilled? If not, why not?