How to Build Your Own Robot Submarine
They can gently manipulate a china cup on the bottom of the ocean, 2 1/2 miles beneath the surface, or inspect the bottom of a boat's hull at the nearest marina.You see them "swimming" around offshore oil platforms and flying above the bow of the Titanic. Stacked with electronics and hydraulics, they have cameras to "see" where they're going and "arms" to move things---they're robots, they're submarines and they're properly called remotely operated vehicles (ROVs).
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Things You'll Need
- Grade 5 titanium (sheets)
- Plasma cutter
- Metal break
- Electron beam welder
- Grade 5 titanium tubing
- SDE-S7 Siemens programmable logic controller
- Compensated junction boxes
- Charged coupled device
- Lexan camera housing (depth-rated)
- LED lights (depth-rated)
- Waterproof screw-on pigtail connectors
- 4 electric thrusters
- Syntactic foam
- Depth-rated umbilical cord, power/control
- ROV Control station
- Data recording devices
Instructions
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1
Build the control module enclosure from grade 5 titanium, which the manufacturer will have stress proofed at 828 MPa, or 8,172 atmospheres (atm). Translate the 8 atmosphere rating to a lowest working depth (LWD) by multiplying the atm by 33: 8,172 x 33 = 269,676 feet LWD---far deeper than the deepest point in the worlds oceans, the Challenger Deep of the Marianas Trench, which only has a depth of 36,201 feet.
Use the plasma cutter to cut the bottom and sides of the control system enclosure as a single piece, and cut the top separately. Bend the sides up with a metal break. Weld the corner seams of the control system enclosure with the electron beam welder, then attach the top with screws and waterproof gasket material rated for 20 atm.
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2
Make two skids, like the runners of a sleigh, from square section grade 5 titanium tubing. Weld two legs to each runner, and weld the legs to the bottom of the control module enclosure.
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3
Install the SDE-S7 Siemens PLC (programmable logic controller) into the control system enclosure with marine adhesive. The PLC becomesthe interface between the control panel on the surface and the ROV's camera and thrusters.
Make all external electrical connections to the control module through compensated junction boxes to prevent water ingress into the control module. Compensated junction boxes will compensate for the difference between internal pressure and pressure "at depth." These connections include the connection from the PLC to the "pigtail" connector for the umbilical (the electronic connection cable that runs to the surface), the thruster connections, and the lighting and camera connections, which can you can run to the same junction box.
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4
Mount a color camera, a charged coupled device (CCD) in a clear Lexan housing rated for the lowest planned depth (LPD)---the greatest depth at which you plan to operate the ROV. Connect the housing directly to the compensated junction box by means of the screw fitting on the housing.
Mount LED lights, rated for LPD, to the sides of the control enclosure, aimed in the same direction as the CCD, and make the power connection to the control enclosure by means of a compensated junction box.
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5
Weld the mountings for the four electric thrusters to the top, bottom and sides of the control enclosure. Mount the thrusters and make the connections to the control system by means of compensated junction boxes.
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6
Mount the custom-made block of syntactic foam to the top of the ROV using the mounting system provided by the foam's maker. Syntactic foam, a structured flotation material, gives the ROV neutral buoyancy (the ability to remain constantly at a specific depth).
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7
Connect the umbilical, which supplies the power and data transmission connection to the ROV, to the pigtail connector. Connect the umbilical to the ROV control station and data recording devices. Lower the ROV into the water, and operate.
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Tips & Warnings
Remember that when working with an ROV you have full control in three dimensions.
Maintain an awareness of the location of your umbilical, lest it become entangled in an obstruction. Should it become entangled, turn the ROV around and follow the umbilical. The ROV will drag the umbilical behind it, pulling it free.
This project involves working with toolsnot usually found around the house. Take appropriate cautions.
