Underwater ROV

5 Articles

Underwater Drone Faces Trial By Water

December 3, 2020 by 7 Comments

Underwater Remote Operated Vehicles, or ROVs as they’re typically known, generally operate by tether. This is due to the poor propagation of radio waves underwater. [Simon] wanted to build such a drone, but elected to go for an alternative design with less strings attached, so to speak. Thus far, there have been challenges along the way. (Video, embedded below.)

The underwater drone uses a 3D printed chassis, replete with googly eyes that go a long way to anthropomorphizing the build. Four motors are used for control, with two for thrust in the horizontal plane and two mounted in the vertical plane for attitude control. This allows the drone to be set up at neutral buoyancy, and moved through the water column with thrust rather than complicated ballast mechanisms. The build aims to eschew tethers, instead using a shorter cable to link to a floating unit which uses radio to communicate with the operator on the shore.

The major struggle facing the build has been sealing the chassis against water ingress. This is where the layered nature of 3D printing is a drawback. Even with several treatments of paint and sealant, [Simon] has been unable to stop water getting inside the drone. Further problems concern the excess amount of ballast required to counteract the drone’s natural buoyancy due to displacement.

Regardless of the struggles, we look forward to seeing the next revision rectify some of the shortcomings of the current build. We’re sure [Simon’s] experience building an electric surfboard will come in handy. Video after the break.

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PVC Submersible ROV

February 10, 2017 by 18 Comments

[mark.brubaker.1] and his crew decided to make a submersible for a school project using PVC pipes as a frame. It has two motors on the back to provide forward thrust and steering as well as a horizontal mounted motor in the middle of the PVC chassis to provide up and down thrust. They used regular motors which they waterproofed by inserting them inside a case full of plumbers wax. We’re not sure how long this will hold at the bottom of the ocean, but it works fine for a school project in the pool. Here’s the instructions on how to make one.

The build is completely analog, the controller is a board with three switches which individually control the different motors. So if you want to turn left, you fired up the right motor. For right you do the opposite and fire up the left motor. Up and down, well, you get the picture. If you have a swimming pool, lake or some water body nearby and you’re looking for a weekend project with your kids, this is a great tip. It’s not an Arduino controlled robot fish, but it’s a first step in that direction; you can later on use the frame to improve on the design and add some electronics.

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Subsea ROV Has 6 Degrees Of Freedom + Autopilot

May 18, 2016 by 16 Comments

This is what happens when you give Norwegian engineering students half a year to develop an ROV for their class.

The team utilized 3D printing to design and print their own thruster propellers and ducts for the ROV. It’s powered by HobbyKing motors with VESC speed controllers. This allows them to get from 0.6 to 30N of thrust from each propeller at 12V. Because of this accuracy they’re able to use a PID system to do automatic pitch, roll and depth control!

The electronics are housed in a 200mm acrylic tube (15mm wall thickness) with aluminum end caps and o-rings — an exact pressure rating is not given, but the team could flood the chamber with non-conductive oil to increase that even more — they just don’t need to for tests in a swimming pool. The undersea wire connectors they use (Subconn) are rated for 700 and 600 bar!

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THP Hacker Bio: Rusty Jehangir

September 5, 2014 by 18 Comments

[Rusty]’s project for the Hackaday Prize is extremely ambitious. He’s planning on sending an autonomous craft across the ocean, from LA to Hawaii, a distance that will end up being well over 2,500 miles The best part about this project? It’s already had some time in the ocean, cruising off the coast of southern California under its own power for a distance of 20km.

Why is [Rusty] doing this? Partly because he wanted to do something no one had ever done before. For him, this meant developing a cheap underwater thruster, building an autonomous solar-powered surfboard for a months-long voyage halfway across the Pacific. It’s a small step to the goal of exploring the deep ocean with his thruster and mostly off the shelf parts, but already [Rusty] has learned a lot about electronics in a marine environment and being confident enough to let a project go on its own for months at a time.

Interview below.

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0.19 Leagues Under The Sea

January 18, 2014 by 20 Comments

ROV

[Doug] and [Kay] have been building a steel 70-foot sailboat for the last few years, and since it’s a little too cold to work outside their home/shop in Oklahoma, they’re bringing their projects inside for the winter. Until it warms up a bit, they’re working on an underwater ROV capable of diving to 3000 feet below the waves, maneuvering on the ocean floor, and sending video and side-scan sonar back to their homebuilt ship.

Like [Doug] and [Kay]’s adventures in shipbuilding, they’re documenting the entire build process of ROV construction via YouTube videos. The first video covers the construction of a pressure vessel out of a huge piece of 10″ ID, half inch wall steel pipe. The design of the ROV will look somewhat like a torpedo, towed by the ship with cameras pointing in all directions.

For communication with the surface everything is passing over a single Cat5 cable. They’re using an Ethernet extender that uses a twisted wire pair to bring Ethernet to the ocean bottom. With that, a few IP webcams relay video up to the ship and a simple Arduino setup allows for control of the ships thrusters.

The thrusters? Instead of an expensive custom solution they’re using off the shelf brushless motors for RC cars and planes. By potting the coils of a brushless outrunner motor, [Doug] and [Kay] found this solution makes an awful lot of sense; it’s cheap, fairly reliable, doesn’t require a whole lot of engineering, and most importantly cheap.

Bunch of videos below, or just check out [Doug] and [Kay]’s progress on their slightly out-of-date blog.

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