I am currently working on a tilt rotor reverse tricopter design and found that when transitioning to forward flight it nosedives into the ground and I could not make it pull up.
I have attached the video of the crash and will try to upload the log file as well, but have you ever seen this before?
Transition looked slow, but really you’ll need to share the .bin log file off the flight controller to really tell anything.
Did you confirm the FBWA stabilization corrections were moving in the right directions?
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Thanks for your response, I am going to confirm the FBWA stabilisation now, and I’ll decrease the transition time now.
The forums won’t let me put the .bin file up for some reason so I’ve uploaded it to dropbox.
Here is the link: https://www.dropbox.com/scl/fi/efjnyztladge9sq3jxs23/00000083.BIN?rlkey=ye99lpeencaq04prts7jo10mn&st=lj9p1s8y&dl=0
The forum will only allow small files, so that’s normal to use the cloud drive of your choice.
The plane never made it up to speed.
I don’t know what that plane needs, but looking at it’s shape on the video I’m going to guess it needs something closer to 15+m/s to fly, and by the time it got close to that it was already in a dive with a planet in the way.
You could try to increase the Q_TILT_MAX so the plane will use the quad motors longer and it might give you more time to accelerate, but I think there’s bigger issues.
I’m confused by your control configuration. I only see one elevator output (servo 2), but no form of roll control. What physical surfaces does the plane have? Does it have elevons? Are the canards supposed to move? Or is the plan to rely on vectored thrust?
I’ll definitely be increasing Q_TILT_MAX.
The control systems for this plane are pretty weird, I’m limited by my flight controller to only 6 outputs and 5 of those are taken up by motors and motor tilt servos so I only have one spare output which I have connected to canards to control the pitch of the airplane. The motor tilt servos then control roll, and they also control pitch. I don’t really need the motors to help in pitch, but I can’t find a way to make it so that they only help in roll.
I’m concerned that because the motors angle down when I give pitch up commands that they might be contributing to the nose-diving and not actually correcting it, I’m hoping that the canards will help with that but I’ve found that when testing on the bench they don’t move a lot in response to pitch changes when in FBWA, is there a way to increase correcting movement only for the elevator output and not for the tilt servos?
It’s common on the bench FBWA doesn’t move a lot. It should move in the proper direction, so double check the stabilization correction is going the right way. Use manual mode on the ground to make sure the controls are traveling far enough based on control inputs.
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