Re: [Paparazzi-devel] AP_MODE_FAILSAFE

[Felix Ruess]

Eric,

> In my understand, the failsafe mode began active when we lost GPS or lost
> Radio, in NAV-MODE

read carefully, its when GPS _and_ radio is lost in nav that you go
into the failsafe mode.

This makes sort of sense, because if you still have RC you can still
control the multicopter, if you don't have RC either.... well, you are
screwed and want to go into the failsafe mode (i.e. set attitude to
zero and slowly descend).


Gautier,
correct me if I'm wrong, but currently nothing is done if you just
loose GPS in nav mode, right?
Maybe we should go into some sort of (other) emergency mode in such a case?

> Also the horizontal control loops in hover and nav mode are slightly
> different, so if you tune in hover, your flight in nav may not be as good.
> So if your goal is to flight in nav mode, trim it in this mode. If you want
> to fly manually and hover from time to time, trim using hover mode.

This is very true, but not very nice...
Assuming for now that you don't use the horizontal reference
(GUIDANCE_H_USE_REF not defined and is hence zero) and you are within
HOLD_DISTANCE, I would expect the same behavior from nav (with "stay"
on a waypoint) as with AP_MODE_HOVER_*

What is the reason we have different scaling between these two modes??
This doesn't really make sense to me.
Any reason not to "fix" this and either change it in function
guidance_h_hover_run (guidance_h.c 243) or guidance_h_nav_run
(guidance_h.c 333)?

What I also just noticed in guidance_h_nav_run:
Shouldn't we reset guidance_h_nav_err to zero if we are within
HOLD_DISTANCE? Otherwise we will continually use an old tracking
nav_err if we get closer than HOLD_DISTANCE to the waypoint.

Cheers, Felix

On Wed, Nov 2, 2011 at 5:53 PM, Eric BAHIER <address@hidden> wrote:
> hi,
>
> I will move to NAV, and I'll define only one stand-by point.... In this case
> th AP_MODE_Failsafe will be applicable, and efficient..
> Thanks,
>
> Eric
>
> Le 02/11/2011 17:45, Gautier Hattenberger a écrit :
>
> Hi,
>
> There is no "almost" nav mode. Being in nav mode means that you are using
> the flight plans instructions to fly. If you really want to only hover while
> being in this mode, you can just make a flight plan that waits for the gps
> and then saty at a given waypoint.
> Also the horizontal control loops in hover and nav mode are slightly
> different, so if you tune in hover, your flight in nav may not be as good.
> So if your goal is to flight in nav mode, trim it in this mode. If you want
> to fly manually and hover from time to time, trim using hover mode.
>
> Gautier
>
> On 02/11/2011 16:53, Eric BAHIER wrote:
>
> hi felix,
>
> In my understand, the failsafe mode began active when we lost GPS or lost
> Radio, in NAV-MODE
>
> I read it on
> :"http://paparazzi.enac.fr/wiki/Rotorcraft_Configuration#Autopilot_modes";,
> your link :
> AP_MODE_FAILSAFE
>
> This is a failsafe mode that gets triggered if:
>
> RC signal is lost (and you are not in KILL or NAV mode)
> GPS and RC is lost in NAV mode
>
> I can accept,  AP_MODE_HOVER_DIRECT and AP_MODE_HOVER_Z_HOLD are not realy
> in NAV mode, but "almost nav mode".
>
> For my test I want first to have AP_MODE_HOVER_Z_HOLD full opperational up
> to  ????xx km/h wind, and move to NAV when the stationair(GPS) fly is done.
> how to, to triggered the AP_MODE_FAILSAFE , for my understand, this setup is
> indépendant from manual/auto1/auto2....I missuterstand?
>
>
> regards,
>
> Eric
>
>
>
> The autopilot will level the rotorcraft out (setpoints to zero pitch and
> roll angles) and descend at 0.5m/s downwards.
>
> Le 02/11/2011 14:29, Eric BAHIER a écrit :
>
> Hi,
>
> I woulds like to use  "AP_MODE_FAILSAFE ".
>
> Currently I use :
>
> <section name="MODE">
>   <define name="MANUAL" value="AP_MODE_ATTITUDE_DIRECT" />
>   <define name="AUTO1" value="AP_MODE_HOVER_DIRECT" />
>   <define name="AUTO2" value="AP_MODE_HOVER_Z_HOLD" />
> </section>
>
> I would like to have "AP_MODE_FAILSAFE" active in HOVERs mode,   is it
> possible?
>
> I probably lost the GPS some time in HOVER.... and the quad go away...where
> it can....  If is stay and land it could be nice for debuging.
>
>
> Where, how to... I will proced to use "AP_MODE_FAILSAFE"....
>
> Thanks,
>
> eric
>
>
>
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> 34 980 Montferrier sur LEZ
> France
>
> Tel : 33 4 67 59 92 53
> Fax : 33 9 59 15 92 53
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