I didn’t manage to find a topic similar to this one, which caught me by a little surprise.
So, we have a problem with vibrations on our BR2. We’ve had our BR2 in heavy configuration for over a year now. It is most often equipped with additional Ping1D and Ping360, elevated with payload skid, and 3 equally separated additional cameras set up on a carbon pole mounted to the front of ROV.
Vibrations that we’ve tracked now seem to be happening for over a year now, in bigger or smaller measure, right about when we upgraded to heavy configuration. We weren’t detecting them before as a problem since camera stabilization (we mainly use GoPros) compensated them, and since vibrations are big enough to be seen on camera during bigger vertical movements, and that is the part of the video that we usually discard/do not use.
So, vibrations are stronger while moving vertically (up/down), and really weak (not noticeable) while moving or rotating in other directions. Also important, vibrations occur during stabilize mode, which we use during our underwater inspections (vibrations do not occur during operating in manual mode). With that said, the cause of vibrations are most likely four of the vertical thrusters.
Also, vibrations got much more visible when we upgraded our underwater GoPro housings to aluminium ones, which are really heavier, so them sticking out on a carbon pole really intensified the vibrations.
Short example of video for GoPro while there are vibrations is here as an example, taken from the left camera:
Our BR2 in this setup looks like this:
To counter the argument that vibrations are caused by cameras on relatively long lever, vibrations are also happening while ROV is without cameras, in water, in stabilize mode (not currently able to video this because ROV is in a different setup now, while testing). With that said, I consider vibration of the camera in this stage as the issue, but not the cause.
The main thing we saw during this whole testing period (which is longer that supposed because of some leaks we’ve been having) is that the “upper” part of ROV (4" tube with 2 aluminium cradle screwed to the ROV side panel via HDPE center panels) does move differently in regards to lower part (3" tube on HDPE bottom panel).
Specificaly, if you apply force to the side of ROV, try to shake it, on our ROV there is a distinct difference in regards of movement that 3" and 4" tube are doing. Since 3" tube is on a solid piece of HDPE, it is shaking considerably less than 4" tube that is on a less sturdy mounting system (2 brackets and 4 HDPE center panels).
I am wondering, did anyone notice this? How did you solve or at least mitigate it?
We are currently experimenting with removing the skid and stiffening upper part of ROV frame with 3D printed pieces and threaded rods, which do seem to help, but still with some work on it.