[octavvian]

Hello, I'm flying a small-medium tricopter with Revolution mini FC, 1400kV motors, 3s Lipo. In alt hold mode, it maintains altitude but in a jumpy like manner. How do I make it fly smoothly in alt hold mode?
Thanks

[Mateusz]

You can tune vertical pids which are for maintaining altitude.

[octavvian]

Thanks, here comes the problem, in witch order i should play with it  ? In the alt hold page in configuration I reduce the first parameter from 70 to 10 and it calms down, but .... not enough.
The 2th and 3th parameter doesn,t do much, and here I stopped and search help.
Thanks for you're help!

[kicekilla]

make sure your baro is protected from sunlight and wind(even the slightest) if it is not. maybe a small price of tissue or opencell foam inside the little case.

[octavvian]

Hi, thanks for the advice, all that is been taken care off... , variation in sys graph is within +/-0.4m there is a black sponge that covers the baro chip. What I'm not happy is the way is done. The transition when altitude is degrading is done fast enough to make it looks like the tricopter is jumping.
I must say that the fly test is done in a room like conditions, not on open space or outside.
 

[TheOtherCliff]

Baros can be a cross between a balancing act and a detective act.

To start with, put the altitude PIDs back to stock.  Then set the thrust limits (found in the same area).  The middle one is the amount of stick it takes to hover.

As mentioned, bouncing baro is usually a matter of not enough foam.  The idea with the foam is that it slows the wind down and it takes more foam than you would think to do it.  It's almost like you seal it with foam that leaks a little.  Too much foam and you have gotten rid of your bouncy, but replaced it with a slow, large vertical oscillation.

Light has a large effect, mostly noticeable when you yaw around.  Easy to test just after sundown to see if this is the case.

Even with enough foam, sometimes wind deflects along the arm and hits the FC sideways.  I would wrap the FC in a 360 degree vertical cardboard fence for a test, especially to block the wind coming along the top of the tail boom from the rear motor.  Maybe put a half a paper cup upside down over the FC with plenty of lip hanging down below the FC.

One of these things should help a lot.  Then try tuning the altitude PIDs.

[octavvian]

Thanks, I'll investigate in that direction to see the results.😀

[kicekilla]

might be worth trying it outside too in some good forward flight?

I honestly have never flown around in altitude hold mode but just hovered around. I'll be retuning my revo quad tomorrow so I will give altitude hold forward flight a try and see how it goes : )

[octavvian]

Thanks, unfortunately here is raining. I'll try an outside run asp  .