Hi Guys,
I hope some one can help me. I have spent quite a bit of time flying quads using multiwii and thought I would try Arducopter get some more functionality.
I spent some time tuning my quad indoors using the method posted by Dave C. I then tuned it outdoors on a still day and was very happy with the results.
They next day I tried to go for a fly when there was a little wind around. Well it felt like I was flying a different quad. It was jumping around like there was something wrong. I landed and checked everything over and found nothing out of place. I tried to fly again with a similar result. I then thought I may have gone a little heavy handed with the the PIDs so I reduced P and I a little with still the same result. The wind calmed down for a moment and I tried again and it was alot better. I thought maybe the lower PIDs had helped then the wind picked up again and it went back to jumping around..
The setup is a X650 airframe
APM2.5
880kv motors
F30A escs
4S 5000ma lipo
The performance on a still day was excellent I could throw it around and be agressive with no problems at all. Just a little wind comes along and the quad is dancing around again. It almost like the power is backed off too much after a correction to a motor ???
Here is a video to demonstrate I am not sure if you can hear the motors pumping during the corrections.
https://www.youtube.com/watch?v=y4YHOz-DlH8
Thanks in Advance
Matt
Replies
@Mathew,
My friend was flying his 3DR hexacopter on Saturday in a 15 - 20 mph breeze and it would not hold altitude just like you describe. He has also installed the sonar so his altitude hold was being controlled by both the sonar and the barometer. Otherwise he had complete control of the copter, but it slowly bounced around like it was on a yoyo.
Just a thought.
Regards,
TCIII
Hi Matt,
Me and my friend were discussing on a similar phenomena with the wind in action for a quadcopter, making it unstable. A line of reasoning we went through was that the 'Natural frequency' of the winds when matched 'the frequency of oscillation' of the quad, then at the resonant frequency the quad may become unstable.
The idea was to choose the right PID values using transfer function of control. Just wanted to share this with you. Although, this was more in theory and aren't sure if this is applicable in your case.
Cheers,
Shyam.
My first thought lies elsewhere. This looks like a mechanical fault, like a bearing is binding, or an esc is playing up.
Or you have got rate_D too high, or you have something out of balance (a cracked prop etc), and the rate_d you are using is amplifying this vibration into a fast oscillation.
So am I right in understanding that this wobble only occurs when it's windy?
Could you post a screen shout of your config page in MP please?
Also I love f30A speed controllers, but not with stock firmware. simonk improved theses ESC's more than any other I've tried.
Hey David,
I am using APM2.5. I have covered the baro sensor with some foam. I have been testing it in Rate/Acro mode. Is the Barometric sensor a factor in Acro mode?
Matt
The first question going through my head was what version of the APM are you using? And if it's APM 2.5, have you covered the barometric sensor?
Cheers,
David.