Presenter:

Mr MM Mabaso

REMOTE OPERATED VEHICLE(ROV)

BACKGROUND

• Deep water operations have been in many years conducted by scuba divers even at conditions where it is unsafe for human such as extremely low temperatures, mine hunting and so on. Medical literature suggest that there are potential chronic long-term detrimental effect of diving such as:

• Decompression sickness (DCS), Nitrogen narcosis, subclinical damage to brain, spinal cord, inner ear, retina and small airways of lung due to extended exposure to increased pressure underwater.

• In the 1950’s ROV’s began to be in operation but their use was very limited due to technology of that time.

OBJETIVES

Design a work class ROV to carry out subsea operations to minimise/eliminate the use of divers

ROV is a tethered underwater mobile device. It is operated by a crew aboard a vessel.

Applications:• Mine hunting and mine

breaking

• Pipeline and platform Inspection

• Subsea installations

• Diver observation

• Object location and recovery

• Capturing scientific images

DESIGN SPECIFICATIONS

• Maximum diving depth: 3Km

• Diving duration: no limit

• Maximum allowable operational speed: 3knots (1,54m/s)

• Frame dimensions: 1,3m0,7m1m

• Weight in air: 100Kg

• Maximum payload: 100Kg

• Propulsion system: 6 propellers and 2 ballast cylinders

• Input power demand: 2Kw

• Neutral buoyant at 1m below ocean surface

• Total variable force: 612N

Launching and recovery system

• ROV is kept aboard a vessel inside a cage.

• It is launched by lifting the cage and dip it into ocean until the ROV is fully submerged.

• Rear thrusters will then propel the ROV forward.

• Recovery is performed the same way, a skilled pilot will steer ROV onto the cage.

• The cage is then brought back aboard a vessel.

Propulsion and buoyancy

• Six propellers and two ballast cylinders are used for propulsion.

• There are two cylinders in x, y and z direction.

• Two ballast cylinders are used as buoyancy control device (BCD).

• Approximately 2Kw is required to drive two thrusters.

• Ballast cylinders will reduce power demand.

Frame

• Frame material must have density close to sea water to allow for easy neutral buoyancy.

• Acrylonitrile Butadiene Styrene (ABS) material was used for a frame

• The frame is design with slots to reduce drag forces on the frame while leaving the room for other components.

• ABS has good corrosion resistance and high yield strength.

Cage and Tether Management System (TMS)

• TMS is used to control the coiling and uncoiling of the cable to avoid over tensioning.

• Tether length is the only factor that will affect diving depth.

Robotic arm and manipulators

• Robotic arm is equipped with interchangeable manipulators.

• It is driven by five motors.

A good material selection and part location played a vital role in stability as it governs centre of buoyancy. This knowledge also ensured that ROV sinks before floating. However in this design conducting underwater welding will be hazardous and will require further design alterations. A further knowledge and research needs to be done to compensate for this drawback

CONCLUSION

QUESTIONS?

THANK YOU