Hi guys! I've just rebuilt my hex onto a new Tarot FY690S frame and put the latest (supported) firmware (3.2.1) onto my APM2.5.2. It seems to want to take off at a very steep pitch angle, and tips over backwards before lift off.
Holding it above my head and giving it some throttle, you can feel the control loop is working correctly (thrusting the correct motors to try and level out), so the FC orientation and motor wiring order/directions seem correct. It just thinks that level is 20-30 degrees tilted backwards!
The FC is mounted flat on the base, I’ve done the accelerometer calibration & level. The artificial horizon in mission planner reports that the hex is level when placed on a flat surface correctly.
Looking at the logs, as soon as the copter is armed, ATT.DesPitch (desired pitch) seems to just jump up to 22 and stay there.
Any ideas what could be causing this?
I've attached a log file. Note that I was holding the copter for this and not in "real" flight.
Replies
Turns out RC_TRIM in the parameters list was around 980, whereas the other channels were around 1480. Forcing it to 1480 gets the hex working normally. Redoing RC calibration however sets it back to 980.
Continuing discussion here https://discuss.ardupilot.org/t/hex-tips-over-on-launch-desired-pit...