Re: [Paparazzi-devel] rotorcraft / throttle sensitivity / rate mode

[Oswald Berthold]

hi felix,

thanks for the nudge.

turns out the multistars don't do calibration [1], so i swapped them for
some other ESCs, now throttle is fine.

spent some time playing with the attitude params. horizontal is fine but
yaw behaviour irritates me.
 - very weak response build-up to yaw stick and equally slow decay of
   yaw response (still yawing on when stick is back to zero).
 - thrust is diminished strongly during yaw
 - during disarm (full yaw, throttle neutral) motors spin up and frame
   tends to jump

i couldn't find any setting for PSI_[PID]GAIN where this would really go
away.

i'm on git master and using essentially
examples/quadrotor_lisa_m_2_pwm_spektrum.xml

bst, oswald


[1] they seem to have worked quite well with a multiwii type system (for
which the tx travel is adjusted to precisely 1000-2000us).


Felix Ruess writes:

> Hi Oswald,
>
> this very much sounds like you either need to calibrate your ESCs and/or
> set up the min,neutral,max properly in your servo section.
> The neutral value should be the pulse length in us at which your ESCs turn
> the motors on, but at an acceptable idle speed. Min is off in that case and
> max is well, max...
>
> This has nothing to do with the gains or anything like that at this
> point... first you need to make sure that if you send the "neutral" value
> all motors will rotate at idle speed and reach their maximum speed at max
> and not before.
>
> I never use rate mode, but the ahrs (attitude estimation) should run as
> normal... and works as expected here...
> Can you provide some more details?
>
> Cheers, Felix
>
>
> On Tue, May 27, 2014 at 10:45 AM, Oswald Berthold <
> address@hidden> wrote:
>
>>
>> dear list,
>>
>> i am very glad finally having a real paparazzi system for work and
>> play. as you're already suspecting, i have some questions.
>>
>> system:
>>  - quadrotor, X configuration
>>  - lisa/m v2
>>  - orange rx satellite
>>  - turnigy multistar 20A ESCs
>>  - git 82d414d8 .. (20140520)
>>
>> throttle issue:
>>  1. arming starts the motors but i have to keep them alive by giving
>>    some more throttle, otherwise some of them starve. igains are zero
>>    for the attitude controller. i cannot raise "neutral" because of the
>>    next subissue
>>  2. i have been able to make a first flight with my provisional PID
>>    settings and throttle seems oversensitive. quad takes off with maybe
>>    20% of stick and it was quite a challenge to hover manually.
>>
>> rate mode issue:
>>  - when i alternatively configure rate mode for switch 1 manual, the PFD
>>    doesn't work. is attitude estimation disabled in rate mode? also, in
>>    messages i see that the phi/theta/psi ests are not updated.
>>
>> regards and thanks for any feedback,
>> opt
>>
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