Two things to tune in ACM2 - help needed - Discussions

After having some problems with previous version of Arducopter code (including ardupirates) i tried current, second version. I must say that im impressed, it flies quite well at default settings ! Quite, because i must solve 2 things, im flying only in stabilise mode as for now.

1. Quad is prestty stable, but also a bit "nervous". From time to time its catching short oscillation, also its oscillating a bit at quick descent. What parameter should i change (rise or lower ?) to correct it ? Wiki suggest to focus at Kd, but maybe in this case its matter of "P" ?

2. This matter is a bit more complicated. During flight with first version of Arducopter (and ardupirates) i noticed that after crazy and fast flight quad its drifting quite strongly to opposite direction for some time. For example if i did some fast forward flight with some turns and so on, and if i try hover just after that - quad drifts backward quite strongly. After some time, about 10-15 seconds quad get back his level and hovering more or less in place again. Also landing and reconnecting battery do work.

Unfortunatelly i see that same behavior with ACM2, but not so strong like in previous version. After fast flight forward and relasing sticks, quad for about 5 seconds tries to drift backward till it get back his level and hover normally. What can be reason of such behavior ? In my opinion, in ACM2 it looks like quad is trying to stop his forward move when i relase sticks, but this "contraction" is too strong making him not only stop, but also drift backward. What parameters i should try change (rise or lower) to correct this ?

My setup:

- APM 1280 + Oilpan (version before 1.4.), no magneto, no sonar, no GPS

- 850 kV RCTimer motors with 10x4.7 APC props

- own frame with 50 cm motor to motor distance

- 1 kg RTF weight

Greg

Replies

Kristian May 31, 2011 at 6:09am

2. I have exactly the same problem that you describe! Sometimes I have to give full stick movement to stop the quad from flying away.. Did you solve this problem?
eduardo May 11, 2011 at 11:04am

if you put too much Ki the AC will back when you release sticks.

Put less i parameter.

As Kp i think that you can change "STABILIZE DAMP"
MB1380 May 11, 2011 at 2:31am

I am also experiencing the short oscillation which you have. I tried changing the D value to -0.1 and +0.1 but both were un flyable. I then lowered the P value to 0.5 and then to 0.4 and it is slightly better but still not right. I also lowered the stabalise damp value but still have oscillation.
Greg May 11, 2011 at 1:45am

Really nobody ?

This reply was deleted.