Hi Guys, i am new to this forum so hopefully i have this post in the right place.
I am having a small issue with with two multi-rotors i have set up. First machine was a quad with 14 inch props, 3508 motors, 6S AUW 2.2kg
Second machine having the same problem is a hex 2212 motors 8 inch prps on 4S AUW 1.9kg
Both machines are fitted with a Pixhawk FC system 3DR compass and GPS. The Hex on default gains is flying quite well and it is stable and agile. The quad was a bit twitchy but stable.
The issue i am having is that if I nudge the roll axes the Hex will level instantly with very little over shoot. However if i nudge the pith axes the machine kind of gets its self into an aggressive resonance back and forth, loses altitude until it hits the ground.
The quad has the same problem on both roll and pitch axes. It you only nudge it a little it can recover and maintain stability. However if you really push it over and let the sticks go back to center - it will set off a resonance which results in the machine rocking 30-40 degrees each way.
I have checked there are no motor sync issues.
Ensured the machine is balanced
Changed props as i thought it could be over powered
Tried 4 and 6S batteries on the Quad
I tried Auto Tune on the hex with 12 inch props at the time and it was rather scary. First half of the auto tune went smoothly however when it go to tuning the pitch axes I thought the machine was going to eat me alive. It basically pitched back and forth at least 40 degrees.
Any advice/help with the issue would be very helpful as i am not sure what else to do?
Flight log for the Hex during auto tune attached
Thanks
Replies
Your PID values will be useful for others to be able to help.
PIDs are all set to default.
I finally discovered my problem. ESC were not calibrated correctly. Very frustrating and such a silly mistake. Basically i was calibrating the ESC all in one through the Pixhawk. Because the ESC's were all ready powered on they had already done the initial voltage check and done the little jingle.
So when you push the safety button the ESC will beep twice straight away to acknowledge that the throttle high has been set. NOTE: you will not hear the little jingle to confirm battery voltage as this has already been done.
So as soon as you push the safety button you will here the two beeps. Then lower the throttle and you will get one solid beep to indicate throttle low has been set.
To check if your calibration is correct just raise the throttle slightly and all motors should start at the same time. If they do not start all together then re-do the calibration.
My problem was that i was waiting for the little jingle then the two beeps which meant the ESC was going in to its programming sequence.