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From: | Stephen L Hulme |
Subject: | Re: [Paparazzi-devel] Talking about Camreras and Wind |
Date: | Fri, 30 Jul 2010 20:07:14 +1200 |
Hi Christophe
Thank you. That clears everything up.
I had set measured high wind speeds and
directions manually previously on the GCS.
Regards
Stephen
On Thu, 29 Jul
2010 23:27:52 +0200 Christophe De
Wagter wrote:
> Sorry about the confusion.
> > We always fly with the -DSTRONG_WIND, even with not strong winds... > > If the wind is strong, you should make sure that the wind estimate is "set" > manually prior to takeoff. Once in flight the wind is estimated by the > groundstation and sent to the plane. But especially during a take-off, the > wind is not known yet to the groundstation while the groundspeed is reduced > due to the climbing, so the plane is very prone to get into trouble (flying > backward). Since it takes a while for the groundstation to have a good > estimate of the wind, it is (always) better to manually guess the wind and > set it. (as long as the direction is good, the amplitude is of less big > importance: set it to something in the range 0.5 x V-CUISE to VCRUISE: if > there is more wind than VCRUISE you shouldnt fly, and less than half VCRUISE > there is no need to set is.) > > > > > On Thu, Jul 29, 2010 at 1:28 PM, Stephen L Hulme <address@hidden>wrote: > >> Dear Christophe >> >> Thank you for the informative reply. >> >> But I think I am still missing something. >> >> When you say "I would say: if the wind comes close to your cruise speed.... >> you should *set it* prior to takeoff" >> >> Do you mean set the flags such as: >> >> ap.CFLAGS += -DNAV -DAGR_CLIMB -DLOITER_TRIM -DWIND_INFO -DSTRONG_WIND >> ap.srcs += nav.c fw_h_ctl.c fw_v_ctl.c >> >> or something else?. And if the wind is low remove the flags? >> >> >> Regards >> >> Stephen >> >> >> On Wed, 28 Jul 2010 22:16:27 +0200 Christophe De Wagter wrote: >> >> >> Dear Stephen, >> >> The wind.xml is redundant as the wind parameters are always present in the >> gcs - settings - flight parameters. >> >> Procedure for strong winds: >> >> I would say: if the wind comes close to your cruise speed.... you should >> set it prior to takeoff. In practice we never set it but always start with >> at least 1 standby circle. >> >> *Without *the "strong wind" procedure when the ground speed becomes zero >> or negative (e.g. when you climb, that reduces your groundspeed), the MAV >> keeps turning even when the nose is pointing in the right direction and >> hereby is blown away. The strong-wind procedure is no miracle but simply >> adds the estimated wind to the ground speed when estimating angles. Even if >> the wind estimation is not accurate but just points in more or less the >> correct quadrant, it makes a huge difference. When the groundspeed becomes >> close to zero, the strongwind function reduces the nav gain (as a small >> heading difference makes the plane move laterally which is seen as a (huge) >> 90 degree error, while the real heading error is only a few degrees). When >> the ground speed becomes negative, the strongwind function uses the >> estimated heading instead of the ground track. This enables you to fly >> backward. Using the formation flight routines in paparazzi you can make a >> "hovering controller" for planes. >> >> Success. >> >> On Wed, Jul 28, 2010 at 12:12 AM, Stephen L Hulme <address@hidden> wrote: >> >>> Hi Everyone >>> ** >>> *Re: Camera:* >>> >>> I have a similar software problem with a Canon IXUS 80IS and CHDK. >>> >>> Following a very kind donation from John Stowers of a Booz main, IMU and >>> power board I have successfully launched a 40cm MK quadrotor. >>> >>> I wish to carry the mentioned cradled Canon camera and remotely trigger >>> still shots using the USB remote configuration.while simultaneously >>> transmitting video over a 5.8 GHz transmitter. >>> >>> To date I am having great difficulty getting the video to display beyond >>> three minutes without the default script appearing on the video image. >>> >>> Any help with a working script would be appreciated. >>> >>> Pascal previously indicated in a PM that one of Antoine's quadrotors was >>> running this setup. >>> >>> *Re :Wind * >>> After crashing my Funjet last summer I came back to test my old the >>> airframe.xml code for a rebuilt version and found the settings file wind.xml >>> has been removed. >>> >>> Christophe De Wagter maybe you could kindly set out the proper procedure >>> to run the strong wind function? >>> >>> >>> Regards >>> >>> >>> Stephen |
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