paparazzi/paparazzi — comment on commit 8b2892c0052ac9b4da597e400e490fa117c44577
File:  line 0
By dewagter:

I totally agree to get rid of the ir_ and ins_ stuff.
I also see some issues with the trim stuff, which is why I put it in a pull
request.

but:

1) to me trimming your plane is a pain in paparazzi. It takes me more time
fine tune the trimming than it takes to tune auto1 and auto2 together.
especially in planes with many servo's and fancy control laws (like the
butterfly mixer on 4 wing servos, and even worse when they have
non symmetrical plays). In manual, on your transmitter you simply push the
trim a bit to the left, but in your airframe file you need to compute
complex new servo ways and I always end up flashing several times before
the trims are what they need to be ...

"when flying in manual, and trimming your plane you ADD a trim to the
COMMAND since the RADIO is directly copied to there"

2) In rotorcraft it is a bit different but in fixedwing (UAV but also full
sized) the fuselage pitch trim angle is not always very straight forward.
Just like in general aviation you turn the knob on the artificial horizon
to remember the zero (no climb at certain airspeed) there is a real need to
be able to change and tune (at least) the pitch angle. Since this is
necessary, it has been hacked to any ir_ and ins_ ...

"Ideally you would TRIM your plane in manual, then align your IMU2BODY in
AUTO1 with the trimmed plane and then auto2 should be perfect right away."

-Christophe

On Wed, Nov 2, 2011 at 6:19 PM, Felix Ruess <
reply@reply.github.com>wrote:

> I would really like to get rid of these damned ad-hoc ir_ and ins_
> neutrals. Antoine already proposed changes to settings so we can
> adjust the imu_to_body directly via settings at runtime. I think that
> would be a much nicer approach to adjust these.
>
> But I'm not sure if we still want to be able to set trims like
> Christophe added here, that are valid in all modes and make it easier
> to trim the actual control surfaces without having to land and adjust
> them mechanically, then fly again...
>
> On Wed, Nov 2, 2011 at 5:28 PM, Gautier Hattenberger
>
> wrote:
> > ir and ins trims are representing the estimation error due to
> misalignment, while a command trim adds an offset after all the control
> loops. If we do that, will we be able to compare properly the attitude
> setpoints with the estimated state ? It's already a problem with the loiter
> and dash trims. If we want to merge these ir_ and ins_ neutrals, it should
> be related to the ahrs interface. It is already with the imu to body
> matrix, but it is only at compile-time. An ahrs_neutrals, available at
> runtime and for small angles, should do the rest.
> >
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