Servers by jDrones

Vibrations or PID gains?

Hi,

I have a hexacopter which shows really high vibrations (I see these in the VIBE measurements in the logs) when it flies in windy environments. However, when there’s almost no wind, I don’t have this issues. As a side note, I haven’t autotuned this copter, so its reactions are slow: when it’s in Loiter mode, some disturbance will move it a couple of centimeters, and then it will return to the desired point after some seconds.

Is this related to vibrations in the Pixhawk or is it because my PIDs are not good enough and I get “vibrations” as the wind moves the copter away? I always use an antivibration mount for my Pixhawk (this one).

I have attached a log file.

Thanks,

Javier
Bin file

How about a pic of the frame or a link to. Some frames have “soft” arms that has caused this for me.

It’s a Tarot T960 frame.

I find foldable frames can be an issue. I would do an autotune first. If no improvement try adding a bit of weight to the FC. I use a 1 one once piece of lead- like a stick-on tire weight on the center of the FC. I fly in Wyoming USA, and to me a 10 -15 MPH wind is a calm breeze! ( I am at 4550 feet above sea level as well) ! I have battled this calm vs. wind issue since I started flying multicomputers. I found firmly attached motor arms are the best. I also use a square of vibe tape ( foam or gel) under the FC where it attaches to the vibration mount. Lots of trial and error involved I am afraid to get good readings

Also props make a difference in dealing with wind. I found that APC props are a bit soft and Master Air Screw one a bit stiffer. I would guess that Carbon fiber are the best, But I don’t want to spend the money on those. I found that dropping prop diameter an inch can really help in handling wind. But this is all trial and error stuff. Be sure you props are balanced.

Joe.

Try to fly one or two minutes in hover without wind and look your vibes, if they are ok, you need tune, if not, try to solve them first. I have 2 Tarot quad frames and go well but I avoid to fold for Joe reason.

Hi,

I did an autotune and my copter is extremely twitchy. Would you mind checking my logs? I think there’s a way to tell the performance of the autotuning, but I don’t know what parameters I should look.

Best,

Javier

Bin file

Servers by jDrones