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Hybrid Aerial Underwater Drone – Bachelor Project [video]

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Re: Hybrid Aerial Underwater Drone – Bachelor Project [video]

#21

Post by jbay808 »

petermcneeley wrote: post #20

As an undergrad project this is rather impressive. But those motors do not look very water resistant. We all know that that shape and those blades are not very efficient in the water. And as others mention the RF signal probably cuts out at a few meters (probably worse in salt water).

Definitely impressive as a proof of concept. A lot of the other problems can be solved with iteration. There are some IP67-rated drone motors meant to both fly and run underwater (available from Westmag for example).

There might be less that can be done about the underwater drag, but if it doesn't need to go long distances underwater that's not as much of a problem. For the RF signal, it can either run autonomously underwater, or use a fibre-optic umbilical, or even convert from an umbilical to wireless when it takes to the air.

Re: Hybrid Aerial Underwater Drone – Bachelor Project [video]

#22

Post by ch4s3 »

engineer_22 wrote: post #16
ch4s3 wrote: post #9

Earlier quoted context omitted.

> imagine what DARPA and the like have been doing for the past 20 years. People always say this, but anyone I know who's ever worked in one of these companies that contracts for the DoD or DARPA always complains about how behind the market government tech is. Obviously private industry isn't producing competitors to the F35, but for less complicated kit the government doesn't seem to be doing anything super sophistic…

> In fact a bunch of people I knew who went to Iraq bought supplemental gear on the private market. Like, photography gear?

No, like armor and rifle optics.

Re: Hybrid Aerial Underwater Drone – Bachelor Project [video]

#24

Post by echoangle »

stoev wrote: post #10

Any ideas how the signal is transmitted once the drone is underwater? Typical RC transmitters run 2.4 GHz. Some systems use 700 MHz. The former wouldn't penetrate at all, the latter might penetrate to a shallow depth, but I think that what's shown in the video is deep enough that the signal would get attenuated. There doesn't seem to be a tether and the drone doesn't seem to have any computer vision capabilities to f…

IMU that determines rotation rates and acceleration without vision. A drone can fly and hold attitude with some accuracy without any outside help, it doesn’t need cameras or outside control. Only GPS to counteract drifting but that can be neglected in the very short term.

Re: Hybrid Aerial Underwater Drone – Bachelor Project [video]

#25

Post by echoangle »

engineer_22 wrote: post #15
lm28469 wrote: post #14

Earlier quoted context omitted.

> I'm almost surprised this doesn't already exist after looking at it. What's the use case? We have very good dedicated aerial drones and very good dedicated submarine drones. If something is technically possible but no one makes it usually it means it's not that interesting

If your mothership is low-observable/submersible you could park it in a harbor and when time is right unleash a swarm of hybrid aerial underwater drones with mission payload. This design uses 1 swashplate server plus 1 brushless drive motor for each prop for a total of 8 motors. Designs in Ukraine are now using 1 brushless drive motor to synchronously drive all 4 props and 1 swashplate servo each prop, reducing total…

Why do the drones need to be able to work underwater? Can’t you just connect some floats to them and launch the drones once they’re at the surface?

Re: Hybrid Aerial Underwater Drone – Bachelor Project [video]

#26

Post by nhma »

stoev wrote: post #10

Any ideas how the signal is transmitted once the drone is underwater? Typical RC transmitters run 2.4 GHz. Some systems use 700 MHz. The former wouldn't penetrate at all, the latter might penetrate to a shallow depth, but I think that what's shown in the video is deep enough that the signal would get attenuated. There doesn't seem to be a tether and the drone doesn't seem to have any computer vision capabilities to f…

As far as I can tell from their report (https://gitlab.com/hybrid-drone/paper), the authors did not consider underwater RF transmissions in their prototype design and simply use standard COTS components typically used for DIY UAVs.

Re: Hybrid Aerial Underwater Drone – Bachelor Project [video]

#27

Post by nhma »

idiotsecant wrote: post #3

Variable pitch! Waterproof! This thing is awesome. Surely there is different tuning when it's in water vs when it's not, right? How do you detect the transition? Motor currents? This is a really neat project!

In their report (https://gitlab.com/hybrid-drone/paper) the authors mention that they implemented one controller for flying and another for diving. The transition seems to be initiated manually, but they propose a few ways of automatic detection and transition.

Re: Hybrid Aerial Underwater Drone – Bachelor Project [video]

#28

Post by tantalor »

> Hybrid drones offer great potential in many industries due to their ability to operate in air and water.

"Hybrid" usually means a combination of features from two different things.

For instance, a car with electric & internal combustion engines.

But here they are using "hybrid" to mean a combination of capabilities. That's different than features.

Also, "hybrid done" already has a meaning:

https://en.wikipedia.org/wiki/Hybrid_drone

Re: Hybrid Aerial Underwater Drone – Bachelor Project [video]

#29

Post by phire »

hermitcrab wrote: post #11

Very impressive. I assume that underwater propulsion uses a lot more energy per meter moved?

But you use spend much less energy fighting gravity.

I’d expect it to have more range underwater than a typical quadcoter has through air. And much longer “flight” time.

But I doubt it gains enough to compete with a fixed wing drone using the same battery.

Re: Hybrid Aerial Underwater Drone – Bachelor Project [video]

#30

Post by stinkbeetle »

tantalor wrote: post #28

> Hybrid drones offer great potential in many industries due to their ability to operate in air and water. "Hybrid" usually means a combination of features from two different things. For instance, a car with electric & internal combustion engines. But here they are using "hybrid" to mean a combination of capabilities . That's different than features. Also, "hybrid done" already has a meaning: https://en.wikipedia.org…

Looks to me like it is a hybrid of an underwater drone thing and an aerial drone thing, and that you have a good opportunity to expand that wiki page to include the other meanings of the term.
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