ECJJ ROV

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shuda716
Posts: 4
Joined: Jul 25th, 2014, 4:38 pm

ECJJ ROV

Post by shuda716 »

Hi everyone!

We are a team of four people and we are making the plans of our ROV. We have a big project. The mission of our ROV is to be able to reach the St-Lawrence river's floor for the purpose of geological research. The ROV is then obligated to be able to resist to a 450 meters depth pressure (46,306577 bars).

The project is base on Raspberry PI and Arduino UNO.

We are still young and we are just beginning our baccalaureates (2 members are studying mechanical engineering, 1 is studying eletrical engineering and I'm studying marine geology), so we have a lot of interogations.

PVC isn't going to resist that much pressure right?
What kind of material should we use for the frame?

So basically, how to start planning it?

Thanks in advance!

NOTE: I'm a french speaker, my english isn't perfect
ssrc30
Posts: 33
Joined: Aug 1st, 2014, 12:26 pm
Location: Alberta, Canada

Re: ECJJ ROV

Post by ssrc30 »

Have you considered maybe going with a pressurized hull of some sort? The Saint Lawrence River is pretty deep so it may be something you want to consider.
shuda716
Posts: 4
Joined: Jul 25th, 2014, 4:38 pm

Re: ECJJ ROV

Post by shuda716 »

And how could we make a pressurized hull? Do you have example of ROV using those?

Thank you!
ssrc30
Posts: 33
Joined: Aug 1st, 2014, 12:26 pm
Location: Alberta, Canada

Re: ECJJ ROV

Post by ssrc30 »

Not off hand but I don't see why it couldn't be done.
TwoBeaner
Posts: 27
Joined: May 24th, 2014, 9:58 am

Re: ECJJ ROV

Post by TwoBeaner »

Welcome, I'm by no means an export (in fact I'm pretty new to this) but her are a few topics form this site on the subject of pressure compensation.

viewtopic.php?f=3&t=1417&hilit=pressure+compensation
viewtopic.php?f=4&t=362&p=1209&hilit=pr ... tion#p1209
viewtopic.php?f=13&t=158&hilit=pressure+compensation
viewtopic.php?f=3&t=92

In all honesty and in my opinion you don't really need pressure compensation. While 47bar (or 650psi) is a lot of pressure a well made metal (maybe aluminum) pressure hull should be able to withstand that no problem. In my mind pressure compensation would be a lot more work... just my thoughts. Any cheers and good luck with your project <><
ssrc30
Posts: 33
Joined: Aug 1st, 2014, 12:26 pm
Location: Alberta, Canada

Re: ECJJ ROV

Post by ssrc30 »

TwoBeaner wrote:Welcome, I'm by no means an export (in fact I'm pretty new to this) but her are a few topics form this site on the subject of pressure compensation.

viewtopic.php?f=3&t=1417&hilit=pressure+compensation
viewtopic.php?f=4&t=362&p=1209&hilit=pr ... tion#p1209
viewtopic.php?f=13&t=158&hilit=pressure+compensation
viewtopic.php?f=3&t=92

In all honesty and in my opinion you don't really need pressure compensation. While 47bar (or 650psi) is a lot of pressure a well made metal (maybe aluminum) pressure hull should be able to withstand that no problem. In my mind pressure compensation would be a lot more work... just my thoughts. Any cheers and good luck with your project <><


I imagine using a single cylinder design suspended inside a seafox style frame would work? I've seen several designs that I think might work really well for a pressurized design. I do agree though, an aluminum material would probably be the best way to go. I'll leave that to people who know more than I do on the subject lol
ssrc30
Posts: 33
Joined: Aug 1st, 2014, 12:26 pm
Location: Alberta, Canada

Re: ECJJ ROV

Post by ssrc30 »

Another thing I've been looking into is motor mounting. Recently I learned that you can, in fact, expose your motors to water and have them still work. Further research tells me this works best with brushless motors and according to my source, should be good as far down as 200' or so. So this begs another design question. Do you stick to the tried and true bilge pump method of propulsion or do you take the plunge and expose your motors to the elements? If both methods are proved, I see no reason why you wouldn't want to try both and go with the one that works best for your application.
scubersteve
Posts: 251
Joined: Jan 28th, 2013, 10:29 pm
Location: Milton, Florida

Re: ECJJ ROV

Post by scubersteve »

I still maintain that the downside to waterproofed motors is that if they do ever leak then they just sit and soak in it inside the case and you don't ever know about it until they quit working.
An exposed motor actually has no depth limit and can be flushed out and oiled between dives.

My 2 cents...
ssrc30
Posts: 33
Joined: Aug 1st, 2014, 12:26 pm
Location: Alberta, Canada

Re: ECJJ ROV

Post by ssrc30 »

Can't help but agree with you on that one. I'm still trying to wrap my head around putting unsealed electrical components in water LOL
perfo
Posts: 151
Joined: Jan 27th, 2015, 12:05 am

Re: ECJJ ROV

Post by perfo »

shuda716 wrote:Hi everyone!

We are a team of four people and we are making the plans of our ROV. We have a big project. The mission of our ROV is to be able to reach the St-Lawrence river's floor for the purpose of geological research. The ROV is then obligated to be able to resist to a 450 meters depth pressure (46,306577 bars).
Hello, I know this is an oldish thread but 450 meters is 45 bar not 46,0000 (which is 6600 psi ish). I not a ROV senior but I do know a bit about other stuff and one thing to bear in mind is a pipe like the injection system on your car can take 1000's of bar because it is small and thus the hoop stress is small. SO just my thoughts but the smaller you can make it in diameter then the less chance you have of crushing.
But as this was from 2014 I guess you already know all this.. :)
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