Uneven thrust from motors + unstable behaiour of ROV in general

control-systems
mechanical
propulsion
software

#1

Runnng a OpenROV 2.8 with the latest 30.0.2 installed.

Recently completed this first build on the ROV and have been having a few issues ever since completion. Put everything together and have reasonably reliable ability to boot it up, get information back to the dashboard and send instructions to the ROV itself, but performance is very unreliable.

Issues:

  1. Thrust is not balanced. At any thrust rating, when I instruct the ROV to move directly forward it veers drastically to the right, as if more thrust is coming out of the left prop.
  • Note that I’ve swapped out the motors with other motors and even swapped them around, yet the thrust is always imbalanced in the same way, so I doubt this is a motor issue and more likely to be a instruction / software issue?
  • One of the six batteries seems to have issues charging, I’m unsure if this would be relevent it seems to be a “low performer”
  1. On multiple occasions the ROV has failed to boot and I’ve had to reinstall the firmware (30.0.2), and perform the subsequent update to the Arduino, this then ususally resolves the start up issue and lets me successfully control and get information back from the ROV (albeit with the issues above).

Here is a text dump of teh error log I got via SSH, but I don’t know if it contains particularly useful information as I can’t really understand it - I got this log after issuing a bunch of thrust (forward, back etc) commands to the unit.

Any help or advice greatly appreciated!


#2

We have released version 30.0.3 of the software which directly addresses the failed boots you have been seeing.


#3

Hi Brian, thanks very much for that - I’d somehow missed 30.0.3.

Have loaded it on and tested today: the boot up seems much more reliable which is great. Differential thrust remains an issue however. I took some video and want to get more logs via the new webSSH tools in the updated software, so I’ll update my post.