Hi
This may sound crazy. How about a quadcopter designed for underwater use. Brushless motors operate perfectly well submerged and the rest can be waterproofed quite easily. Idea being that one would use small props, basically the quad would operate in a different medium but essentially it should still stabilise as it does in air. I thought about escs (which don't like water) getting hot but they could be exposed, covered with tectyl or some other waterproofing spray.
As a fail-safe, waterquad would be slightly buoyant so in case of power loss, it would merely float to the surface. One would then have keep throttle on all the time to stay submerged and power up to sink as opposed to normal operation. I know that 2.4ghz does not work underwater but the older 35mhz systems do. For fpv, 1.3ghz could be used ?? Also I wonder which flight controller would work best, kk2 maybe for cost-effectiveness.
Has this been attempted before and if so, any success? Couldn't seem to find anything on this concept. I'm itching to start building but somebody please stop me if I'm wasting my time.
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Shall I start a new thread ? or is it ok to add to this one and ask my own questions ?
My thoughts are the control system underwater needs to be a lot slower so any PID controller would have different parameters so the thing slowly rights it self.
The Air props would put too much load on to the motors ? Wouldn't they ?
Can anyone suggest a DIY type set up ? If I make one (which I'm hoping to). Can the folks on here suggest a motor and controller set up etc? The motors ideally would be ok to run in fresh water without any special waterproofing... Hovering would be the most important thing for me to get close up stable video. I'm even thinking that maybe tilt switches would be sufficient to tell it when it is upright or not. I'm going to admit my ignorance here and ask.. Does the quad have to tip when moving forward/backwards or side to side or can t it do it whilst being level ?
have a look at http://www.bluerobotics.com/thruster/
these look perfect if you can speed control them which I guess you can however at $138 per motor they are going to be way out of my budget for four of them on my test craft... thanks for the link...
would something like the turnigy SK450 be a good donor craft ? It appears to have all the bits I'd need. I'm conscious of the fact that I'll probably drown this thing so I don't want to spend too much until I've got the ideas sorted. Can I get something like the SK450 without the radio gear and save some cash? ... Also has anyone got any hints how I could interface the radio inputs to a raspberry PI so I can control it over a network ...
I don't think this sounds crazy at all.
I have done some testing of 2.4ghz under water and there is no way to get it to travel any where near enough distance to control and underwater quad. In fresh water you may get up to 16cm if everything is perfect but less than 10cm is more likely. The lower frequencies do work thought the antennae get bigger but if you are intending to get video from the quad then the bandwidth on these become a problem..
I am looking in to the same thing as this but will tether mine. at present I'm intending to use a fiber optic to command and get data back..
I'm tempted to get hold of a real cheap quad and convert it by swapping the air props for boat props and sticking a raspberry pi on it to handle the fiber optic conversion and camera stuff. Water proof the whole thing and see how it goes. I would opt for neutral buoyancy if possible if anything a slight negative would be advantageous.
Did you get anywhere with this ?
Thanks
Check this out:
https://www.youtube.com/watch?v=UaRpTclSwX0
Great video, I will reiterate though getting live video stream from that camera will be impossible over radio link once you are more than a jiffy under the surface and if the controls are on 2.4ghz then they will not be far behind...
I would be curious to know if you have done any progress on this project. I was just thinking about something very similar.
something you may have trouble with in regards to slight buoyancy is the deeper you go (and this is assuming your using air as the medium to obtain buoyancy) is it can get harder to obtain depth as you go further down, kind of like a pool noodle is hard to keep down when you want it down (its a bit like drag, and will require more power). Now I know the following idea may sound more complicated, but you could use a very small can of compressed air (or maybe co2) with a small water proof inflatable sack thats programmed to inflate on command or when fail-safe activates. just a thought, Good luck and I hope to see your results!
Quadcopter for underwater use? Well, I don't think it is a bad idea. Be careful with the design of copter orientation system.
Read more at http://robotics.stackexchange.com/questions/1466/quadcopter-applica...
What I understand from it is that the quadcopter for underwater use is a possible thing. And hope you know the importance of hydraulic lubrication systems. Repairs should be done immediately.
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