Bluerov2 heavy issue with yaw 270 navigator mounting

Hello all,
I’m running a 8-thruster configured rov with navigator & continuous power supply.
firmware version: 4.1.1
version: blueos 1.1.1
navigator mounted at yaw270 degree instead of roll90.

issues that I’m facing:

  1. rov not moving straight or back, rather in an arc.
  2. stabilize and depth hold modes are not working properly.
  3. thruster auto detection is continuously FAILING at thruster-1 itself. message is showing to check thruster-1 & frame setup.

I’ve thoroughly checked the ESCs and connections to the navigator. Everything is fine. Thrusters orientation and combinations are all correct.

Hi @surajbilung
Sorry you’re having issues! Some troubleshooting questions:

  1. Did you calibrate the ROV accelerometer and compass with the unit completely assembled, and far away from magnetic influences?
  2. When the thruster auto-detection fails, is the vehicle floating in water, free to move?
  3. When you say the stabilize/depth modes aren’t working, I wouldn’t expect the unit to therefore be able to drive in a straight line. What happens when you switch to those modes? If the vehicle “goes crazy” and moves violently, the thrusters may not be where the vehicle expects them to be based on the frame definition, or they may need to be reversed. You can check and set each motor direction without the auto-detection, it’s just a touch more time consuming.

If all else fails, trying another autopilot orientation may be helpful to determine what’s going wrong? I’d be interested in how your high-current carrying wires route in relation to the Navigator as well…

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hi @tony-white
thank you and sorry for late reply

  1. yes i calibrated the ROV accelerometer and compass with the unit completely assembled and far away from magnetic influences.
    2.yes, ROV’s thruster auto-detection is performed in water only, when auto-detection start the 1st thruster turns the ROV but in QGC it show “failed! check thruster 1 and frame setup”
  2. we manually check and set each motor direction without the auto-detection, the ROV seems to work in stabilize/depth modes but not perfectly, but in manual mode when forward or backward is given through joystick, ROV moves in a Arc instead of going in straight line .

Please note that , we also have a custom frame to which some extra components are added.
Some signal and power lines are going beside the navigator. Do you think that might be an issue. Do you or your team have any idea on how much current carrying wires are allowed to pass through beside navigator.

Hi @surajbilung -
I would recommend swapping the ESC used for thruster 1 with the ESC from another thruster, to see if the issue follows the thruster. This may be what’s happening, if the motion of the vehicle is less then expected. In manual mode you should not expect the vehicle to drive a perfect straight line, but if it is traveling in an Arc is may be due to poor performance of one of the lateral thrusters, hence my suspicion.
If that proves to be the culprit, using that ESC for a vertical thruster may reduce the impact on performance while you wait for a replacement.

A bad sensor calibration is possible - were the scores in the green zone post calibration? This is shown in QGround Control. Routing power wires in close proximity to the Navigator could definitely be causing poor performance in stabilize/depth hold mode - can you detail what exactly is not perfect? It is possible that the general design of your vehicle is causing issues if generally asymmetric or unstable?

In our ROV, we are using 4 T500 thrusters for horizontal motion & 4 T200 thrusters for vertical motion. The navigator is mounted in Yaw 270.
After a few trials, I am able to drive the ROV in a straight path in Depth hold mode and stabilize mode. But in manual mode it’s moving in an arc.
For calibration, I have used both conventional way where the result was in green jone and also fast calibration method. I thought fast calibration will be more effective since the ROV weight is around 34kg. Please note that the ROV is perfectly symmetric and stable.

Since some extra components are added to the ROV, we had to pass some minor current carrying devices like multibeam sonar, USBL, DVL, etc.

The issues that I am currently facing are

  1. ROV moving in an arc in manual mode
  2. Sometimes the ROV gains auto depth in stabilize mode
  3. The navigator is placed in Yaw 270 orientation, but in fast calibration, the ROV is working with Yaw 90 settings, which I am wondering how is that possibble.

Plz let us know.

Hi @surajbilung -

  1. Unfortunately, the ROV driving in an arc in manual mode is expected behavior, and cannot be corrected - this is what stabilize mode is for!
  2. In stabilize mode, depth is not controlled, so it is on the user to adjust. If the vehicle is positively buoyant, this means the operator would need to apply downward thrust occasionally. This is what depth hold is for! It is stabilize mode + depth control based on pressure sensor.
  3. We’re investigating the auto motor calibration with different orientation settings, but if yaw 90 and yaw 270 is equivalent in your setup, and one works, it sounds like you’re all set!
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