Jordi's been doing lots of test flights of ArduPilot 2.1 and 2.2 in preparation for the Sparkfun autonomous vehicle contest. These new versions of ArduPilot include throttle control to help it handle wind better. Today seemed like a good day to test that. Jordi describes what happened:
"Today i went to test my ArduPilor and winds were about 15mph with gusts of 25mph, EasyStar was having a difficult flight due to the high winds, and suddenly the EasyStar climb for about 200 meters and start drifting away from launch pad (maybe at that altitude the currents were a lot more stronger)....
It was cloudy and I lost it in the sky and i was looking on the ground station how ArduPilot was trying to fighting against the wind, but the motor was almost off because the autopilot was trying to go down, but unable to travel forward, was going left and right, against the wind....
I tried to spot it on the sky over and over again to retake control, also looking into the ground station to know the direction but nothing! at that moment it was around 400 meters high!
In a matter of seconds the last position i got was 2500 meters away!! at 50 meters altitude, then i lost signal!! So i quickly took the coordinates and i made the calculation of the crash site (you know, with the last altitude and the heading i can estimate more or less the crash area, the battery was drained so no thrust at all). I've put the coordinates in motionX (iPhone app) and i begun the searching deep into the mountains!
The easystar was suposed to be lost, forever!!! And i was impressed with the range of the modem, normally i lost signal at 500 meters!
Then when i spotted i could't believe it!!
And OMG i still don't know how i find it, that was horrible, hills and canyon... That was for sure luck...
Reto, Ardupilot uses airspeed sensor and gps altitude, and the altitude error set the desired airspeed PID that controls throttle and also move a little bit the elevators... But that day was to windy....
When ArduPilot was falling down was with the battery empty, the motor control shut down the motor to protect the LIPO, but i still transmitting data, the problem was that mountain, it was blocking the signal!
I hope the FAA aint following the runup to the Sparkfun event, what with planes in TV towers, and another with loss of control at altitude.
I hear those boys have neither a sense of adventure, nor a sense of humour!
Glad to see you got your plane back. Its situations like this that it would be nice to have a small battery backup and transmitting Gps coordinates to the ground-station every minute or so.That's to say the equipment is still working.
Hi Jordi, great you found your plane! Did you break your personal longest distance flight?
You said the motor was programmed off to loose altitude. I wonder if there would be a way to have the throttle varying based on ground speed with some threshold parameter set specifically to the implemented airframe.
Comments
When ArduPilot was falling down was with the battery empty, the motor control shut down the motor to protect the LIPO, but i still transmitting data, the problem was that mountain, it was blocking the signal!
I hear those boys have neither a sense of adventure, nor a sense of humour!
Glad to you get your plane back.
Thx Benjamin.
Erwin
Do you think it turned downwind slightly and then got itself rushed downwind or did it keep its nose into wind and as power dropped got blown back??
You said the motor was programmed off to loose altitude. I wonder if there would be a way to have the throttle varying based on ground speed with some threshold parameter set specifically to the implemented airframe.
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