Naze 32 changes trim when changing flight mode

[biggestRCEfan]

I have a FT tough tilt tri with naze 32 acro. The issue I have is that I need to trim differently in pitch when switching between rate, angle and horizon modes. For the moment i sorted this by programming my taranis, but I dont understand why the control laws have a different static off-set when changing mode. Any ideas?

[2ma]

I have the same but as I only fly accro now… I think It’s just a matter of balancing your tri 🙂

[biggestRCEfan]

Yes, 2ma, it is a matter of balancing. I found that you could trim the Angle mode here, under the flight test part.

Disarm, max throttle, move pitch and roll stick(s) to counter the drift in Angle mode. The result is stored in acc_pitch_trim and acc_roll_trim (get trim in CLI will show the correct parameter names in cleanflight). The values are stored by the board – no further action required before power off.

When you move pitch/roll stick(s) (one channel at a time), the green LED will blink for every two increment/decrement in the relevant parameter, which gives you an indication how far you are trimming.

[LeoTheHuman]

I think that 2ma meant that if your CG is in the center and your accelerometer is calibrated correctly (flat horizontal surface, no trims) you should need no trims for either mode. Accelerometer trims are indeed required if you didn’t calibrate on the horizontal surface or have weird CG.

[biggestRCEfan]

@Leo, yes, I understood it as such. Once I sorted out the basic gains and had a stable hover, in Acro mode, the tri was sitting dead-still with very minor drift with hands off the controls. For me this meant the CG and level surface calibration was good. When I switched to Angle mode, there was a distinct and immediate forward tilt (I would say around 5 deg tilt) with the resultant forward acceleration to a steady speed.

I therefore thought there must be a way to trim the angle mode, as the CG and initial calibration was good for the Acro mode, so must be good for Angle mode.

My search lead to to the linked forum entry. I extract the relevant text from sdueck (thanks mate):

Trimming The Accelerometers (Autolevel)

This is necessary if when you switch to AL mode the quad drifts. Keep in mind this is Autolevel, and not position hold. Autolevel will only level the quad, not keep it in one place. That would be GPS hold. Anyway, Autolevel does need to be trimmed in order to allow it to level the quad, so it doesn’t inherintly drift without the force of wind. This is done by trimming the accelerometers. Keep in mind that they need to have been calibrated through the GUI in the earlier steps.

This write up was done by machina.Thanks for writing this. I will test it out and see how it works once I can find some time with no wind.

This can be done by landing the quad, disarming and pushing the throttle stick to the top. Now your right stick and modify the trim held by the autolevel. If it drifts left, move the stick right. If it drifts back, move the stick forward. Each ‘tick’ will be indicated by a beep (If you installed a speaker) or LED flash from the quad. The ‘ticks’ are very small; I usually go 3-4 ticks per adjustment in the beginning. From there you can refine it to the point where it’s one tick.

Also, do the initial trimming by switching on auto level in flight after takeoff, low to the ground. Mine was very bad initially and it would move wildly. Trying to trim autolevel by activating the auto level and then take off is very, very unpredictable.

Then it’s trimmed in. ONLY do this after you have gyro only flight is trimmed in. Otherwise the two conflict with each other and your quad won’t be happy.

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