Difficulties tuning up the APM and airframe

I did the maiden flight this evening with the APM. I’m using ArduPilotMega 1.02 version dated 10 Jan’11. I have MTK GPS module configured with GPS_PROTOCOL_MTK (not MTK16). I followed all the protocol and everything seems to work OK. The start up sequence works fine, GPS locked, HappyKillmore GCS show right GPS location and attitude of the model, on ground “Stabilize” mode test  look fine, banking and pitching the model the surfaces moves in the right direction. So, “Manual” mode and take off. After a couple of minutes in Manual to trim and check that everything is OK I switched to “Stabilize” and… “ups!”.. the model pitched down hard. I had to give full stick up to fight against the APM that tried to put the model direct on the ground. After landing, I reduced SERVO_PITCH_P and tacked off again. The behavior in “Stabilize” is erratic, some time pitched down, sometime pitched up, and the most stable I got switchin to STAB was the model rolling to inverted and flying in this position. Yes, you understood well, stable flight but inverted. I ordered today the Xbee down link and next weekend will try again but with telemetry to see what it is going on onboard. Somebody has an  idea? What can be wrong?

 

I need help!!

 

You need to be a member of diydrones to add comments!

Join diydrones

Email me when people reply –

Replies

  • Developer
    Doesn't sound like a PID problem at all. Play with the airframe on the ground in STABILIZE of FBW_A and see if you can determine what is going on. If it is happy upside down I guarantee it is not a PID issue....
  • 3D Robotics

    Are you sure you've got the board oriented right? GPS connector forward.

     

    What aircraft are you using? It's worked perfectly right out of the box on every aircraft I've tried, from FunJets to Skywalkers.

     

     

This reply was deleted.

Activity

Neville Rodrigues liked Neville Rodrigues's profile
Jun 30
Santiago Perez liked Santiago Perez's profile
Jun 21
More…