Droplet V2: tetherless BlueROV2 retrofit for research on autonomy and localization. Underwater cave dives & next steps


Droplet 2 collecting data in a cenote

To support our particular style of underwater field robotics research, we are developing an AUV platform called Droplet that is a tetherless BlueROV2 retrofit with industrial quality sensors and an easy ROS based interface for programming the robot. It’s my goal to keep working on this thing throughout my Ph.D. until it is a reliable and open source platform for doing autonomous underwater robotics. There currently aren’t any good options out there that allow you to just jump in and use ROS to control a tetherless AUV.

I wrote up the lessons learned about our platform and suggestions for next steps during a particularly difficult field deployment in Mexico.

I’d appreciate any criticism on the way we are doing things or ideas about how to do things better.

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Hi @slensgra, this progress is really cool to see! :smiley:

I enjoyed the writeup, and particularly like the wifi access and display. It’s worth noting that while an aluminium tube would definitely help with keeping things cool, it would also make wifi and the diver-friendly display harder to get working. The display may be able to be replaced with a few penetrated indicators, or perhaps just one with an RGB led or similar, although lights at the back are likely not quite as convenient as being able to just look through the sides. Perhaps it would also be possible to have an external wifi antenna via a penetrator, although I’m less certain of that (as a side-effect, that could be placed such that it’s out of the water without the vehicle needing to be lifted when it’s at the surface).

Have you considered using some sort of leak sensor for better handling of leaks? If you’re expecting that leaks may occur and you don’t want to stop operation for a slow one, perhaps you could allocate a small section at the bottom of the enclosure with a highly absorbent material in it (to avoid splashes/sloshing), and potentially have leak detection above and in that section, to detect when a leak starts, and when it gets severe enough that switching off is essential.

More generally, given the ideas behind this system, we’d love if you could share some thoughts on autonomy in marine robotics:

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Well done, @slensgra! This is an awesome project and great write up. I also really like the wifi access and display additions you’ve made. That dock looks like a pretty fun place to write some code :wink:

I think an aluminum tube would help substantially with the heat dissipation. It makes a pretty big difference, but it’s also harder to see what’s going on inside. The buna O-rings should be fine for this temperature range. They can get pretty hot before they would fail. I’d be more concerned about having to open/close the tube a lot, which could lead to damage or debris in the O-ring.

It adds a lot to the price, but I’d also consider adding a DVL like the ones from Water Linked or Cerulean! That solves a lot of problems in making it autonomous.

Excited to see your progress!

-Rusty

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Hi Sam! As I am sure you have gathered from Rusty and Eliot’s feedback, we are really enjoying this project! Would you mind if we shared about this on our social media as well?

Thank you!

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Thank you all for taking a look! Please feel free to share on social media.

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