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First dive with T200 thruster


(Chris) #1

Here is my ROV after its first dive with its new t200 thruster. It started as a high school project one year ago. Back then I used selfmade magnetic coupled thrusters, but the vertical thruster used for diving had way too less power and the coupling would slip when spinning too fast. So I now replaced it with an t200. And i have to say, I’m blown away by it. The ROV dives extremley fast and can be controlled very accurately.

I’m looking into replacing the two horizontal thrusters with BR thrusters too. But I still have to decide between the t100 and the t200. Has anyone a recommendation which thruster to use for which size of ROV? My ROV weighs 22kg in air and +1kg in water and is about as aquadynamic as a brick :wink:

Goal of this ROV build is to design it as versatile as possible. The frame is made from item aluminium extrusions which allow to easily add components to the frame and move them around. The electronics consist of an arduino which is linked to the surface PC via a modified power lan module.

Cheers :slight_smile:

Chris




(Harold Scadden) #2

Chris - interesting unit! What are all the various modules that you can see in the picture? Inquiring minds want to know.

 


(Chris) #3

The aluminium tube in the center is the main pressure vessel which contains the communications and control electronics. The long acrylic tubes on the side are the batteries (One 12V LiPo which powers the electronics and t200 and one 7.2 NiMh which powers the horizontal thrusters). The two short tubes on the front are the LED lights ( not hooked up yet). And the small tube towards the center is a simple cctv camera that transmits a video signal to the surface station via the tether. You can also see the lead weights on either side. These add stability to the rov (in combination with the topside buoyancy foam) and are a weight “reserve” for future additions.


(Rusty) #4

Chris,

I’m really impressed by your ROV. I think you thought things through really well and designed well. I’m blown away by the fact that you did this in high school. You should let me know if you’re interested in internships :wink:

Regarding the thruster choice, I would personally go with the T200s to provide some margin, slightly better efficiency, and to stay consistent with your other thruster. That said, either one should work well.

Best regards,

Rusty


(Chris) #5

Thanks for your advice, Rusty. I will go with the T200 thruster, so I sure have enough power.

An internship is definitvely a thrilling idea to me, since I just finished high school and currently taking a gap year. So if this really is an option, I would be happy to discuss it in more detail. :wink:

Kind regards

Chris


(Rusty) #6

Chris,

For sure. Send me an email at rusty@bluerobotics.com.

-Rusty


(Richard) #7

Chris,

Nice work. Impressive, especially on the high school level.

I have a few questions if you don’t mind:

What is the primary and secondary purpose of your new ROV?

Are you operating it in salt water?

To what depth have you tested your ROV in operation?

How does it do in a 1 knot, or so, current?

What material are you using for the tether/signal cable?

Thanks, and keep up your really neat work,

Richard


(Chris) #8

Hi Richard

Of course I don’t mind :wink:

The purpose of the ROV is to provide a low-cost and and modular platform for all kinds of exploration and research. I am especially interested in exploring wrecks in a nearby lake.

By now I’ve only operated in fresh water.

In operation, the ROV has been to about 10m. I had the chance to test the main components of it in a medical hyperbaric chamber. At maximum pressure of the chamber (50m) , all the components were still intact and leak proof. (Though the ROV wasn’t operational then, because they don’t allow any batteries in the chamber)

In the lake where I have tested the ROV I never had to deal with currents. I guess, with the current setup I wouldn’t be able to hold my position in even the lightest current. The selfmade horizontal thrusters which are mounted at the moment provide way too little thrust. I’m sure this will improve with the new t200 thrusters :smiley:

The tether consists of 100m standard cat5 ethernet cable. I found a very lightweight and cheap cable which is very close to neutrally buoyant. I also attach a cave line to the ROV . Just in case I have to pull it out of the water. (I don’t really trust in the breaking strenght of that cat5 cable)

All the best

Chris


(Richard) #9

Thanks for answering the questions Chris. For your operating environment you can certainly get away with a bulky, high drag structure. For the ocean environment I am building for every component must be as small as possible to avoid drag. For example, I am working on air inflating the cat5e cable to give it positive buoyancy and reduce the drag and chance for entanglement on the reef structure. Just the cctv portion should be up and running in the next few weeks, then I will move on to adding two thrusters for directional control. Lots of fun, huh? I am 75 and get the same satisfaction in building something unique, as you also do. Good luck and keep us posted on your progress.