Hi,
Maybe you can look at this
http://lists.gnu.org/archive/html/paparazzi-devel/2012-06/msg00107.html
It looks very similar.
Gautier
Le 08/09/2012 23:10, Mitchell SLOWER a
écrit :
I think you are right Eduardo.
The attitude estimation when taking off with bungee might be
not perfect, we should try the int_cmpl_quat_gravity_heuristic
written by Felix.
As I said before, I thought it was some I-term winding up, so
I tried to decrease, even set to zero the two I-terms used in
the control loops: v_ctl_auto_pitch_igain
and v_ctl_auto_airspeed_igain. No improvement.
Improvement happened when I commented out in the config file
the auto pitch inner loop parameters: V_CTL_AUTO_PITCH_PGAIN
et V_CTL_AUTO_PITCH_IGAIN. The plane was not diving dangerously
anymore, but not getting altitude, just gliding on its track.
Regards,
2012/9/8 Eduardo lavratti <address@hidden>
Felix, the behavior that mitchel say is completely
different than the takeoff with bungee.
BTW, some week ago i tested the auto takeoff using
bungee and this behavior not occur.
because of this i think its a integrator problem.
i see int the code that some integrator are reset when
manual are engaged.
I not remember if it is a throttle or climb integrator.
Date: Sat, 8 Sep 2012 22:47:53 +0200
From: address@hidden
To: address@hidden
Subject: Re: [Paparazzi-devel] Strange behavior:
pitch down when engaging AUTO2, only after launch.
I'm pretty sure that
the AHRS_GRAVITY_UPDATE_NORM_HEURISTIC in 4.0.1
has almost no effect compared to not having it
defined.
Whereas the improvements in
my int_cmpl_quat_gravity_heuristic clearly
should help a lot (if the acceleration of the
bungee takeoff is indeed the problem).
At least in simulation I see a large
(temporary) pitch error of up to ~20deg before
the improvements (of course depends on duration
and acceleration in bungee takeoff) before the
improvements.
On Sat, Sep 8, 2012 at 10:42 PM, Mitchell
SLOWER <address@hidden>
wrote:
Felix,
I did a bungee test in AUTO1
with AHRS_GRAVITY_UPDATE_NORM_HEURISTIC
(4.0.1). It worked.
2012/9/8 Felix Ruess <address@hidden>
Hi,
the pitching down after a
bungee takeoff is definitely
noticable, however from what you
describe I'm not sure if that is
the only effect you are seeing.
you can test the improved
gravity norm heuristic from
my int_cmpl_quat_gravity_heuristic
branch which is up-to-date with
v4.0 otherwise.
Would be great to get some
feedback on this as I can't test
this with a real bungee takeoff
myself.
Cheers, Felix
On Sat, Sep 8, 2012 at
10:19 PM, Eduardo lavratti
<address@hidden>
wrote:
I have the same
behavior.
i am using float_dcm
and bungee but i
think this is not
due bungee.
this behavior occur
if i engage auto2
when pitching up.
If i pitch up,
stabilize altitude
and engage auto2
this behavior not
occur.
this seem that some
I term are working
but i not have time
to search the cause.
i have to make this
test.
takeoff in manual
then engage auto2.
this will reset the
integrator.
regards
Date: Sat, 8
Sep 2012 21:57:52
+0200
From: address@hidden
To: address@hidden
Subject: Re:
[Paparazzi-devel]
Strange behavior:
pitch down when
engaging AUTO2,
only after launch.
Marc,
Christophe:
initially, I
thought it
could be an
AHRS related
problem, but
I'm think it's
something
else.
(I'm using
int_cmpl_quat
and the
AHRS_GRAVITY_UPDATE_NORM_HEURISTIC
flag).
I think
it's not
related to
AHRS because:
- I had a
look at the
estimator
(theta), and
pitch seems to
be correct.
- If I
lauch with the
capatult, fly
some time in
manual, and
engage AUTO2,
diving also
happens.
- When I
disable the
airspeed from
the airframe
config file,
everything
seems to work
(I say "seems"
because I did
only one try
that was
successful).
Regards,
Mitchell
2012/9/8
Christophe De
Wagter <address@hidden>
We have
implemented
the
acceleration
feedback in
It has
flown several
times,
including
catapult
launches but
with the
complexity of
all aspects
involved (e.g.
gps latency
etc.) that is
not a
guarantee. If
you would be
so kind to
help test it
it would be
highly
appreciated.
copy the
file to your
repo, add USE_AHRS_GPS_ACCELERATIONS to
your airframe
(should pop a
message during
compile)
-Christophe
On Sat,
Sep 8, 2012 at
8:58 PM, Marc
Schwarzbach <address@hidden>
wrote:
Hi Mitchell,
your problem
seems to be an
AHRS
calculation
thing related
with the high
acceleration
at bungee
take-off.
See the
conversation
one month ago:
Subject: Re:
[Paparazzi-devel]
int_cmpl_quat
and bungee
takeoff
As a short
note, I had a
similar, but
very light
behaviour when
hand throwing
my Easystar
also with
Lisa/M. It
does a little
pitch down
before
starting to
climb after
the throw...
Probably we
should look
into the ACC
signals for
fixed wing..
Cheers
Marc
--------
Original-Nachricht
--------
> Datum:
Sat, 8 Sep
2012 20:37:18
+0200
> Von:
Mitchell
SLOWER <address@hidden>
> An: address@hidden
> Betreff:
[Paparazzi-devel]
Strange
behavior:
pitch down
when engaging
AUTO2, only
after launch.
> Dear all,
>
> I
encounter a
really strange
behavior on a
fixedwing.
> I had a
look at the
logs, made a
lot of flights
in order to
find out
> what's
> wrong,
but I really
don't
understand
what's
happening.
> So here
is the
situation:
>
> First,
the setup:
> Lisa/M
2.0, PPZ
Version:
4.0.1. I'm
using an
airspeed
sensor,
> I'm
launching the
plane with a
bungee, in
manual mode.
> Before
launch,
current clock
is set to
circle over
home, 150m
AGL.
>
> What's
happening:
> After
launch, when I
change to
AUTO2 , the
plane does not
pitch up with
> motor on
as expected in
order to reach
the desired
altitude, but
pitches
> down,
gaining
airspeed and
loosing
altitude (I
checked that
airspeed is
> near or
over desired
airspeed when
I switch
mode).
>
> As things
get dangerous,
I switch to
MANUAL, get
some altitude,
engage
> AUTO2,
and the same
behavior
occurs.
> Then,
after a few
tries like
this,
everything
works ! And it
works really
> fine, as
I have a very
good airspeed
control and
climb rate.
> After
that, I can
switch from
MANUAL to
AUTO2, and the
plane behaves
> normally
(get some
altitude at
the right
airspeed and
climbrate).
>
> I did a
lot of tests
(I initially
thought of a
I-term winding
up), all
> were
>
unsuccessful.
> The only
clue I found:
this problem
might be
related to the
airspeed
> specific
control loops,
because when I
disable the
airspeed
sensor from
> the
> airframe
config file
the plane
seems to
behave
correctly (no
pitch down
> when
engaging
auto2).
>
> Did
anyone
encounter the
same behavior
?
> Do you
have any idea
about what
could be
happening ?
>
> Of
course, I can
provide
further
details, setup
and logs.
>
> Regards,
> Mitchell
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