Vtol oscillate in pitch while back transition

still, once within rtl radius, the plane would transition and try to capture WP speed as quickly as possible , even if it means braking in VTOL mode and waste the energy you have in fixed wing mode, right? i’m going to do some more complete tests about this behavior, but i suspect there is no way to set up an efficient coasting transition to land in an auto mission.

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Try reducing THR_MAX so there is less effort to attain the Q_WP_SPEED.

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I will try that in my next testing

@akhil I had a look at your log ‘2021-02-16 09-59-59.bin’ and found a few things:

  • it hasn’t gone through the basic setup process for tuning a quadplane. See Tuning Process Instructions — Plane documentation - for example battery range not setup for voltage compensation.
  • the motor expo is set very low (0.25). Do you have thrust stand data that supports such a low value?
  • it is a very old firmware (4.0.1). That firmware doesn’t have the changes to link the rate controller demand between elevator and VTOL motors. I notice there is a phase difference between the two:

that phase difference comes from the different time constants. This makes will make the issue worse.

I’d recommend you do the following:

The above is quite likely to greatly reduce the issue. If not then please post a log and we’ll have another look.
Cheers, Tridge

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I’m having the same issue, sharp pitch up followed by pitch oscillations during auto mission detransitions. Manual detransitions are smooth with no issues.

On a separate note, there is also a small pitch oscillation while in fixed wing auto mode. This happens even after the fixed wing autotune, any advice on smoothing that out?

Attached is the log, any help would be great. Aircraft if a quad, with tractor motor in nose. Thanks


logs are not accessible. I’ve sent an access request, but best to make it public

Oh, thanks. I made it public.

Hi @Gromitvt10 and @tridge - curious if you’ve made any progress on this issue?

Yes, Tridge fixed the main issue in 4.1.3 I think. That plus a bunch of quad-tuning smoothed it out. Flies great now. Changing transition deceleration to 1.3 helped too.

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Did some more testing and yes Q_TRANS_DECEL makes a significant difference, as it was designed to. Changes the vtol pos1 distance quite a lot.