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Autonomous movement through fish net cage

Hi

I’m in the process of trying to get our custom ROV made by BlueROV2 parts to move through a fish net cage in an autonomous way. The thought is that the ROV get put in the water and by a press of a button it moves through a specific pattern through the fish net cage. This is thought to be used in the aquaculture and the fish net cage is cylindrical with an diameter of around 160m and 20m deep.

The ROV is for now set up with 3 thrusters. One to push the ROV to the fish net cage, one to move it sideways and one to regulate the depth.
My initial thought is that I give an constant signal to the thruster that are pushing the ROV into the fish net cage. This signal can be regulated to the specific value after testing out the optimal.
My other thought is that the ROV uses Depth hold to regulate the ROV through the whole fish net cage. And with the use of compass heading the last thruster can move the ROV around the cage so that the whole cage is covered.

My thought is the following scenario:

  • ROV is armed with the press of an button
  • Put ROV in water
  • Push ROV into fish net cage
  • Register heading (ex 359 degrees)
  • Move ROV in an clockwise motion until heading 359 is reached
  • Move ROV 1 meter down
  • Repeat same clockwise motion
  • Repeat this action until ex depth of 15m, then return to depth of 1m

Any thought of where I can start to get something like this done?

With regards to ‘programming’ your rov with the steps you listed, you can use pymavlink to do that.

But there is a problem with this that it won’t work for very long before the rov gets stuck on the net. The currents and fish and other interactions will cause the rov to go off of your desired course very quickly. To follow exactly the path you want without mistakes (and to be able to do it in a current too), you need some ‘position feedback’, like the underwater gps.