Hi.
I have a problem after updating AC to 3.2.1 from 3.1.5.
When in Loiter, the the speed of the motors rev up and down/pulsate quite rapidly. This was working fine when I was using previous versions of arducopter.
I have downloaded the logs, and have looked into accX, accY and accZ. These seems to be inside the range specified in the wiki at arducopter. (Log_vibrations.bin)
Please have a look at the Log.bin, and note the difference between ThrIn and ThrOut when I'm in Loiter mode.
Anyone having any idea what the problem may be?
Replies
Your graph diverges with "no problem for the moment" ;)
1. What is power setup? motor kV, props.
2. Did you do autotune? It greatly helps to find starting point for further tuning.
3. It is pretty strange to have ROLL overshot after high speed flight, it there something you didn't tell us? ;) :)
4. If you are confident about 1-3 are working as should be, try lowering P on roll axis.
What I have'nt tell is that If I let go my stick of roll very gently , it would not overshot ,even after a high speed flight. I guess the reason for that if my frame is too light. After a hight speed flight the vehicle would climb normally , the althold controller have to reduce the THR_OUT to keep the vehicle from climbing .Once the THR_OUT been reduced ,the stb controller can't hold the fram stabile ,so it overshot !
There is common manual what you should do, to get drone in the air.
It is on apm wiki, and if you follow all the instructions there it will get better.
I know it could seem, that it flies OK and it is awfully boring to do everything from scratch, but for now there is no other option.
I like to skip some steps myself and I should admit, there is no easier way than through manual.
1. Wizard.
2. Autotune.
3. PID extra tuning if needed.
Right now you are trying to tune advanced parameter, when basic parameters are not in good shape. It's a good way to have headache.
I mean no problem WITH althold,it just roll and pitch got overshoot. the althold is good!
my setup :HEXA frame size 680mm F4006 KV680 30A blheli 1238 4S5000 2400g
I have'nt done autotune. my pid is so large now, rate_p =0.25 rate_i=0.25 rate_d =0.024 , I am not sure autotune can success or necessary,since the loiter mode is very good ,soild in the air.
the only problem is overshot after high speed flight ,if I let go roll stick quickly.
I have tried lower rate_p to 0.185 ,the overshot get bad,almost to 70 degree,So I don't know, should I keep raise my rate_p , since it is so large already now!
Just try autotune. It will do everything as it needs to be.
Handtuning PID is like searching for a cat in dark room by smell :)
My PIDs were WAY too far from default values.
But still I recommend extreme caution, 700mm quad is no small thing.
Still consistent with my theory since the change was between 3.2. and 3.2.1 :)
Yes, but 3.2 has a lot of useful features that 3.1.5 does not have.
/!\ Message for Dvelopers, please respond. /!\
Obi Van Kenobi, you are our only hope.
Can we use complimentary filter as it is shown in this artice?
It might not require as much resources and speed as EKF, but it could give fresh breath to APM 2.x platform.
Comments appreciated.
It's not that simple. The reason 3.3 is pixhawk specific is because it uses EKF only for navigation - which is too slow to run on an APM. So pulling in features would require that you avoid EKF stuff - and that permeates the 3.3 codebase. Better to fork 3.2.1 and fix specific bugs as they come up. Like this one :)
+1 on that notion... I wish I was a developer to be able to contribute... I will gladly donate to the cause...in appreciation.
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