Re: [Paparazzi-devel] Updated: Tiny13+ArduIMU Multiplex Merlin project

[Christoph Niemann]

Hi David,

did you try increasing the throttle on the ground? Is the attidude information correct in this case? What kind of gyros are on your type of arduimu? I'm using also thatcher Sensor Board equipped with thatcher ST Sensors. It is working very well but the Gyros are a little bit sesitive to vibrations and if the IMU is coupled too hard with the airframe i was also experiencing Problems like you. I solved it by fixing the IMU on the battery and making the battery moveable within the fuselage (with foam).  For the sensorboard and pretty much every other analog IMU I integrated the DCM Code into Paparazzi. It is available in the current forker for ethischen on Github: https://github.com/chni/paparazzi .
I shop this is a help for you.

Cheers

Christoph

Am 01.12.2010 04:39 schrieb "David Conger" <address@hidden>:

Hello,

Just an update. I was able to power all servos from the BEC. Only the PPM wire from the autopilot goes to the servos. Ground and power to the servos comes from the BEC now. 

I was able to fly. However, during sustained turns the autopilot commanded a sharp roll which I was able to recover from. It is consistently doing it. Also if the autopilot starts level it tends to stay level. However if you engage AUTO2 while the aircraft is not level it does not recover well (or at all). 

This was confusing as I am told others are flying with this same IMU and code. So I searched YouTube and found someone flying but now I realize with different code. video: http://www.youtube.com/watch?v=H1rGYIDLKIE&list=ULKKPsIyq1E8Q&playnext=1 

That video was using the 6DOF razor which is just a sensor board. So the DCM code must be running on the autopilot in this case. In my case with the ArduIMU the attitude information comes from the ArduIMU. So if it's incorrect the autopilot is unaware. 

Did I miss something? I have a video showing the attitude information is correct on the ground. However in flight it simply is failing to stabilize my little Merlin aircraft. I am hoping maybe there is a tuning parameter I am missing someone can share with me to correct. 

I have not flown in weeks so I hope to get some new data soon.  However my questions are:
1. Am I supposed to be tuning the IMU somehow? If so how? 
2. The only video of a working example is not using an AHRS. Has anyone a video or proof of a Tiny+ArduIMU flying? Logs that can be replayed? Anything? I heard of a FunJet...can they share some more info to back up the claim and help me get flying. I have a FunJet BTW as well setup to go but don't dare try if the Merlin won't fly. I just am not sure where to start to try and tune this IMU or if it's possible. If someone is flying with it hopefully they can help. 

Regards,
-David

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