Converting blueROV into AUV (removing tether)

Is there a guide of any sort that details how one would go about removing the tether from the blueROV? I already have a well-tested control system that I have added to the rov and don’t use the QGC interface at all anymore. We are just looking to remove the tether cable and have the raspberry pi host the various 192.168.2.2… pages over wifi. I have had success recently with connecting to a Jetson Nano via mobile hotspot on my windows PC. Wondering if I could do something similar with the raspberry pi on blueROV then remove tether all together

Hi @cmarq -
Is your intention to remove the tether but maintain connection via WiFi? This would work, until the drone is immersed in water, which blocks the transmission of wireless RF signals. So you could connect to the vehicle wirelessly, tell it to start the mission, and then splash it - if it operates autonomously it should then return? You won’t have a wireless connection until the WiFi antenna of the device is above water.

Hi Anthony,

Yes, this is the plan. We have already tested fail safes based on depth/velocity feedback to terminate the mission if anything misbehaves. We will also be pool-bound for a while before moving to any open water tests. My main concern is that I would like to have wifi connection and qgroundcontrol to have some gui feedback for calibrating sensors, but I am fully expecting no direct feedback once the vehicle is submerged

Have you taken a look at Mission Robotics, and their computing platform? They still use a topside software component, but have some of the hardware parts worked out.

And, with some of the new DVL tech (we are using some Cerulean and very happy) WP and AUTO missions have become fairly trivial.

We are interested in testing some AUV functionalities as well, so please keep us posted on your progress!

I’ve done this a couple of ways - the first being to have a WiFi network on the boat that the ROV is configured to join and then you can access the BlueOS web UI via the router-assigned IP. This is the way I’d recommend since you can ensure you’re connected whenever the ROV is at the surface. The BlueOS hotspot is another way of doing this, but that doesn’t do our use case.

As far as the ROV itself, we replaced the tether’s penetrator with a BlueTrail Ethernet connector and can connect/disconnect the tether depending on what we’re trying to do at the time. Having the tether is useful for connecting realtime debugging but no one wants to have to open the bottle to remove it. I highly recommend the BlueTrail connectors for this. You have to pot them yourself, but worth it.

Our specific configuration is to join a Starlink terminal’s WiFi network when at the surface. We also have some software on the ROV that powers down BTLE and WiFi when we descend because there’s no point in keeping those powered up while submerged. Our software does a bunch of other stuff, but that’s just one useful feature.

Hi Chandler,

I will check them out, we are using the waterlinked DVL and it has greatly increased the ability to dead-reckon on our vehicle

Will do!

Hi Matt,

I was thinking to use the mobile hotspot functionality on my laptop. Any idea if you can access QGC through wifi connection? I am sure you can, but just wanted to see if anyone had experience with it so I don’t have to waste a whole day trying to figure it out.

The ethernet connector is a great idea, I had thought of it, but hadn’t gotten as far as figuring out how to do it in practice.

Starlink on the surface is pretty sweet. And that’s a good point about disabling unnecessary functionality when it is not needed

Hi @cmarq -
QGC can be used through any TCP/IP connection from vehicle to client computer - you just need to define the appropriate IP address under Mavlink Routes (pirate mode.) You’ll select UDP client and enter the IP address of your target control computer. This works over services like ZeroTier to let you operate the vehicle from anywhere in the world!

Anthony,

Pirate mode is in the new blueOS if I’m not mistaken. Can similar steps be taken in the Companion software?

I have updated to blueOS. Are there any tutorials on how I may add an endpoint such that the raspberry pi onboard can communicate with QGC over WiFi? Preferably by connecting the raspberry pi to my PC’s mobile hotspot

Hi @cmarq -
Welcolme to BlueOS! It would have been possible to setup a mavlink route with Companion, but would have involved a bit trickier process vs. the GUI provided in BlueOS for mavlink routes. Our documentation covers this lightly, but I’ve provided more detail here.

For your particular situation -

  1. Connect to BlueOS via ethernet, with your IP set to 192.168.2.1, subnet mask 255.255.25.0
  2. Click the WiFi icon in the upper right and select your mobile hotspot, enter in any password, and verify you get connected with an IP address on the WiFi network.
  3. In BlueOS, navigate to MAVLink Endpoints on the left menu, and click the plus in the lower right hand corner.
  4. Name your endpoint, and select UDP Client. Then specify the IP address of your client computer on the WiFi network.
  5. Leave the port information as is - no other changes. Click Create Endpoint.

If you have QGroundControl open on the computer, it should immediately start receiving telemetry. If you need to also receive the video feed, this is possible by adjusting the target IP under the Video Streams menu, but I would not expect your connection to be high-quality and able to send the video smoothly. The vehicle can only send video to one IP address at a time, currently.

I hope that’s helpful! Sorry for the delayed response

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Hi Anthony,

Thank you so much for that walkthrough. I followed it exactly and it worked just like you described. I can now remove the tether from our BlueROV and interact over QGroundControl and the online dashboard perfectly.

I have one other question, I am using a waterlinked DVL and it was very nice to be able to go to 192.168.2.95 and view the DVL web interface for monitoring temperature, etc. l cannot seem to replicate this now that I have the tether removed. Do you know of any way to replicate this? My networking knowledge is definitely not as robust as I’d like

Hi @cmarq
When you remove the tether, your connected computer is no longer on the 192.168.2 subnet - that’s why you can’t access the DVL. You are connected to the Raspberry Pi WiFi, so in order to reach the DVL you would have to do some fancy trickery with a web tunnel or network rules within BlueOS - I’m not super familiar with this myself, but it may be possible to still reach the DVL. I’ve wanted this ability in other contexts, so I’ll look into it and see if I can find a solution. Generally if your DVL is in the water temperature should no longer be an issue for it though!

Ah, yeah that makes sense. The ethernet made it possible to connect to the DVL directly instead of having to go through the raspberry pi for it now.

True that it’s a non-issue when it’s in the water. If you find a clean solution, or if I happen upon one, I’ll put an update to the thread

Thanks for your help!

Hi @cmarq, Genuinly interested in your work here and hope its working well for you. A few questions:

  • Do you have a GPS chip mounted to the vehicle to bring in spatial awareness?
  • If not, how are you mission planning in QGC?
  • Do you have to reset the DVL to 0,0 manually before each mission to get it to run?

I definitely need to do some work in auto mode (have a waterlinked as well) to figure out how to create a mission without geographic waypoints.
Thanks,
Mike

Hi @cmarq -
We’ve got a new extension in the store, that’s still in development, but may help you out! Check out the BlueOS Proxy extension - you may have to click extension by blue robotics at the left side for it to appear (along with being connected to internet.)
image

Once installed, click the menu entry on the left added for it. You can then enter in whatever IP and port you’d like to access, and after you click save and open, it will load that in another tab, as if you were connected to that network. Let us know how it goes!

Hey Anthony,

Any idea what the ip should be for this to work with waterlinked DVL?

Hi @cmarq -
I believe you earlier shared the IP you had been accessing the DVL at? This is what you put into the proxy extension - it lets you open a connection to this device even though your wireless connection is on a different subnet (via the Pi WiFi radio.)

I tried that and it was not successful. Unsure what the issue is there

Hi @cmarq -
If you can, I’d recommend connecting to the ROV via tether and seeing if you can reach the DVL on your computer at that address, or if your configuration of the DVL indicates it is at another address? Whatever it comes up at, that is the address you put into the proxy extension.