Depth Hold Problems?

btrue · January 31, 2021, 1:09am

Has anyone else experienced problems with the Depth Hold autopilot where it just fires the downward thrusters at full power when the Depth Hold is engaged? It’s happened to me 3 times now, 2 times in a row last November and once again today. The weird thing is that is works exactly as expected except for those 3 specific times.

The first clip I was accidentally flying in Stabilized mode and the problem happened the moment I switched to Depth Hold. I then disarmed the thrusters, and then the problem repeated itself as soon as I tried Depth Hold again.

The second clip is the start of the dive. I flew it manually away from shore a few feet and then the problem happened exactly the same as the other 2 times. I then disarmed the thrusters as usual, but then Depth Hold worked as expected for the rest of the dive.

williangalvani · February 5, 2021, 2:13am

Hi @btrue !

Thank you for sharing your dives!

I believe the depth-hold issue is caused by the I-term of the depth-hold not being reset when switching into it from stabilize (and other modes).

I made a test build to fix it, you cant try it here. Please let me know if this fixes the issue so we can put out a 4.0.3 release.

btrue · February 2, 2021, 3:42am

@williangalvani Thanks for the super fast support!
Is there anything I can do to ‘force’ the issue to happen when flying to make sure that it’s the cause? Should I try to compare the old and new versions to see if it’s the fix, or just use the new version and see if the problem disappears? It’s a intermittent problem for me right now so it might be hard to tell if it’s really fixed, though it only happened when Depth Hold is engaged, so I can try switching between Stabilized and Depth hold every minute or 2 and see what happens.

Edit: What do I do with the .apj file?

williangalvani · February 2, 2021, 2:03pm

Hi. To flash the .apj file, navigate to http://192.168.2.2:2770/system
and click “choose file”.

I was able to replicate the issue by going into depth hold, switching to stabilize, going up or down to change depth, and switching back into depth hold.

btrue · February 5, 2021, 2:18am

@williangalvani I tried the test build today and there was no sign of the problem, so far it’s looking like it’s fixed. Was this a known issue or was I the first person to mention it? It seems like other people should have experienced it before I did.

almathisen · February 5, 2021, 8:10am

We had this problem before, but we was not able to track down the issue.

williangalvani · February 5, 2021, 2:27pm

Yes, we had reports of it but we were unable to replicate it properly to narrow down the issue. When you reported it, I gave it another try and managed to track it down.

schleitauche · February 12, 2021, 7:56pm

Hi,
how did you record the thruster sounds?
Chris

btrue · February 13, 2021, 3:42am

@schleitauche It’s the audio from the GoPro Hero 4 Silver mounted on the front (shown as the top left part of the video). Right now I sync the videos for the GoPro and the ROV stream with my phone camera flash as shown in the bottom picture at: Soap Lake, WA 1/29/2021 (Shallow Dive)

schleitauche · February 13, 2021, 8:18am

A Gopro, I thought as much. That makes videos some more interesting. Thanks!