stability tricopter

[Ludodg]

I tried to balance the Tricopter, i.e. I placed it on a perfectly flat tabel (checked it with level tool), all the landing gear-pods are of the same height, ....
I then hooked the Tri, which has a Flip 1.5 FC to the PC and via de the MultiWiiConf-software, did a calibration of the gyro's.

But every time that I get the Tri to fly up, when I should be able to let go of the controls because of the ANGle- and/or HORIZON-functions being applied ...
the Tricopter tilts sideways slightly and drifts away.
I can only get it te be moderatly syable when applying some constant stick (ailerons and elevator).

How is that? Should the Tri not have to stabalise itself with the Horizon or Angle-functions aplied? where do i go wrong?

 

[C0d3M0nk3y]

I think you need to calibrate the accelerometers. Those are used by self leveling modes, not the gyros.

Also, don't expect it to be perfectly stable because you have self leveling on. You'll still have give lots of input on the sticks to keep the copter hovering in one spot.

 

[le3dmax]

Here's the link about the ACC calibration/trim.
It's very easy to do it.

http://www.multiwii.com/wiki/index.php?title=Calibration_Accelerometer

"Trim

you will have to use the TX stick combo
Give full throttle** (must be >1900) ** Caution!! Don't forget to DISARM before you give "full throttle"
With the help of your roll and pitch stick you could now trim the ACC mode.
full PITCH forward/backward and full ROLL left/right (2 axis possibilities) will trim the level mode according to the neutral angle you want to change.
The status LED will blink to confirm each ticks.
So for instance, you have to move the pitch stick full forward about 4-5x. That means from neutral to full and back to neutral, 4-5 times. You will here the buzzer each time beep and see the led each time blink, when move full forward. The same for the roll axis.

If you want to reset the ACC trims, just perform ACC calibration Once you have it trimmed do not calibrate acc again as you will loose the stick trim settings"



I've found this videos as well, but I never tried this method.

https://www.youtube.com/watch?v=knagzCgXGEg

But I think you can start calibrating the ACC just like the video then use the regular ACC Trim before you flight in case you still need some fine tuning.

NOTE: IF in case you need to calibrate you ACC, You'll lose all your Acc trimming. You'll need to trim it again.
Have fun! LD

 

[jhitesma]

ACC cal and trim are very different. Usually you shouldn't need much if any trim if you have a proper calibration.

The only time's I've had to use ACC trim is if I had a bad cal or something else wrong with my setup that was causing issues. It's an ok band-aid fix but my experience seems to indicate that if you need to use ACC trim there's probably something else wrong on your setup that you're missing.

That said it's not that bad to dial in some ACC trim for testing. Just use one or two notches at a time (disarm, then throttle at full and push your roll/pitch stick in the direction you want to add some trim.) So if you're drifting left and need to give right roll to correct you'd disarm, give full throttle while disarmed, then give full right roll until the light blinks and release. Repeat that right roll 2-3 times and then pop it back in the air and see how it does. Rinse wash repeat until you're happy!

The warpquad I built with a motowii board for some reason would never calibrate right. Even flat on on a level table after calibration I'd be 2-3 degrees off on my pitch/roll afterwards. Instead of dialing in trim I just shimmed the quad so it wasn't sitting level when calibrating to compensate. Not sure what it was about that quad/board but it pretty much had to have a manual gyro cal run before each flight and the acc never zero'd out unless I shimmed or used trim.