Massive wobbles when entering loiter while drifting in stabilize mode

[Bill]

I';m sure my APM 2.8 never used to do this but it';s going to cost me my multirotor if I don';t figure it out soon!.

It doesn';t happen if I get it completely stationary before flipping the switch, but if it';s drifting slightly then it goes crazy tail down then throws itself nose down and left and right (in no particular order) until I flip the switch back out again or it sorts itself out sometimes.

Any ideas please guys?.  Hopefully it';s just a parameter that I need to adjust. I';ll edit a video and make it available tonight. Cheers

[Bill]

https://youtu.be/_RdrOwLVizY

[Paul01]

You';ll need to adjust the loiter PIDs

Sent from my HTC One_M8 using Tapatalk

[Bill]

You';ll need to adjust the loiter PIDs

Sent from my HTC One_M8 using Tapatalk

Reduce them you mean?.

I';ve already adjusted them down from default slightly as I was getting little oscillations in wind and flight.

[Paul01]

POS_XY_P (shown as "Loiter PID P" at the top right of the screen shot above) convert the horizontal position error (i.e difference between the desired position and the actual position) to a desired speed towards the target position. It is generally not required to adjust this.

VEL_XY_P (shown as "Rate Loiter P, I and D") convert the desired speed towards the target to a desired acceleration. The resulting desired acceleration becomes a lean angle which is then passed to the same angular controller used by Stabilize mode. It is generally not required to adjust this.

According to APM docs you need to be adjust Rate Loiter P, I & D and not Loiter PID P

[Paul01]

Your loiter speed is set to 1000, I';m pretty sure it should be 500 by default

[Bill]

Something is very weird, I can';t adjust Loiter PID P back to its default of 1.0000 or any other value, it just jumps to 0.100 when I hit write params.

Edit: Got it back by just typing "1" and enter, but I got a message saying the value was out of range and to accept anyway y/n?.

I like it with a fast loiter speed but I will try putting it back to 500cm/s. Cheers

[Bill]

Nope, now Loiter PID P is stuck on 0.000 and wont change for anything .

[Paul01]

Might be time to backup your settings, reset and start from scratch.

[Bill]

Yeah that';s what I';m close to!.

Although it';s a pain I can adjust the settings from the full param list OK it seems.

Will try these settings next.

[Paul01]

Yeah that';s what I';m close to!.

Although it';s a pain I can adjust the settings from the full param list OK it seems.

More then likely a bug with Mission Planner as I think its no longer supported.

[Bill]

I';ve just tried the new settings and it';s still doing it but only when drifting forwards or backwards. Holds from a left or right drift nicel and soft.

Will try the following next to see if it has any effect then I';ll look into tuning it properly if it does. It was facing south when I tested it so would I be right in tuning down the Lat PIDs?. I can';t find hardly any info on these individual Lat/Long settings so it';s just trial and error.

[Bill]

After another experiment it seems that it';s only doing it while drifting forward and as far as I can tell nothing else has any effect such as such as if facing north south east or west.

CG is perfect.

Loiter is very sluggish and slow to make the multirototor hold steady if activated when drifting in any other direction such as backwards, left, or right.

Time to start from scratch by the sound of it?😞.