Hi everybody
I have a rather odd problem:
I built a dji 450 flame wheel quad-copter with a pixhawk flight controller. I installed the firmware, chose the frame type (x), performed an accelerometer calibration, calibrated the compass and the radio and set up the flight modes an fail safes. When I got out to test it, the copter flipped over the front right and didn't take off. I took it back in and tried to feel the motor speed whilst I gave no input for the roll/pitch and discovered that the front right motor spun much slower than the others. I pressed the "calibrate level" button in missionplaner which performs a 1-axis calibration of the accelerometer. After that, all motors spun equally. I got out again and did a second test. This time the copter flew towards me and to the right so I cut the throttle and did a ground direction test: I increased the throttle so the craft just didn't take off. Then I gave input for the roll and pitch in each direction to see if the copter leans in the right direction. The result was very weird: Left, Right and Backwards worked fine (the right motors spun faster and the copter leaned in the right direction). When I gave input for the forward direction, however, the copter leaned back instead and to the right. and the motors spun up so fast it even took off and flipped right over. It did that every time it wanted to correct in the forward direction it looked to me and then over corrected to the front because it was obviously leaning in the wrong direction, causing it to flip over. Unfortunately I can't recalibrate the accelerometer because of the bug in missionplaner where it always skips a direction and therefore fails to do the calibration but I don't think the accelerometer is causing it because the artificial horizon in missionplaner is moving correctly as i move the quad. Do you have any idea why my forward pitch is misbehaving and how I can fix it?
Here are the details about my build:
Frame: dji flame wheel 450
Motors: dji 2312
ESCs: dji e420 lite
Radio receiver: FrSKY X8R (connected over a ppm encoder)
External GPS and compass: Ublox 7M
Thank you in advance
Replies
Ok yes it seems like the simple mode switch was the problem since everything worked out fine now. Kind of awkward but I'm happy that I can fly now :D
I think I got it to work by accident. I previously had a determined switch to switch between normal, simple and super simple mode and I guess that somehow didn't work as expected and confused it. I wanted to make another testflight and switched channel 7 to emergency stop instead of super simple and now everything worked fine it looked like. Not quite sure yet since the battery was just empty so I have to recharge it right now. I will post how it worked out later.
I will post some datalogs later
I would assume this is an APM hardware as the X8R works natively on the Pixhawk. Second thing is turn up the logging and let us see what the logs think of your test fights.
Have not heard of any calibration issue with mission planner. Have done this calibration many times without issue.