Just did my maiden flight today and, well… it was rough. The whole flight had a ton of vibrations—way more than I expected—and things just felt off from the start. Flight was pretty short. Took off in Loiter and the drone felt wobbly and jittery, so I got nervous and hit land at about 7-8 meters. Instead, it kept on climbing all the way up to about 30 meters before finally deciding to land. Definitely not what I was hoping for. Here is the log file of flight.
Not really sure why it decided to shoot up like that even after I hit land at a much lower altitude, but here’s another weird thing I noticed while testing on the bench (no props). When I nudge the throttle just a bit above center, the throttle percent shoots up to 90-95% even though the stick is barely moved. Then it slowly drops back down to hover throttle on its own. This weird throttle overshoot wasn’t an issue at all with my smaller drone—no big spikes at center stick.
I’ve attached the log file if anyone wants to take a look. Happy to get any advice or pointers about what might be going wrong or what to check next.
Right now, I’m running an old Pixhawk FMUv3 on firmware 4.3.7. I was thinking of moving to 4.6.2 soon, but I had some previous flight data from a lighter drone on 4.3.7 and thought I’d stick with that for now—maybe that’s a mistake?
I’m actually planning to upgrade to a Cube Orange+ once things are tuned and behaving themselves. Just using the FMUv3 as a kind of “crash test dummy” while I figure out the parameters and tuning, so if (or when) something goes wrong, it’s not a total hardware loss. Does it make sense to tune with FMUv3 and then move the settings over to Cube Orange+? Or will I run into compatibility headaches with parameters or behavior?
Would really appreciate any tips for chasing down these vibrations, or general advice about the altitude weirdness on land. Also, if there are gotchas with migrating params between these controllers, would love a heads up.
Thanks in advance for any help. Really want to get this thing flying right before I swap to the new hardware!
There are a lot of things that you did wrong: the first flight must be done in stabalize, loiter can only be used after a couple on things are correctly tuned and configured. No wonder it skyrocketed like that.
Use ArduPilot methodic configurator software to fix those issues fast and safely.
The software can reset your FC to it’s default parameters
Thanks so much for the quick responses, @Allister and @amilcarlucas! I appreciate the advice.
Just to clarify, I did actually start with the default parameters before this flight. I went through the initial tuning steps recommended by Mission Planner, and the log you were looking at is from that flight.
I’ve also been using the Methodic Configurator software and have made a little progress. I’ve gradually tweaked the PID parameters for Roll and Pitch, and the drone feels a bit better, but it’s definitely not perfect. I’ve hit a point where I think I need some expert help to get it dialed in properly. Here is the log file which is sort of better now.
Also, I’m pretty sure I figured out why it shot up so fast on takeoff. It seems to have been due to the TKOFF_THR_MAX parameter, which was set to something high. I’ve since changed it to 0, which should make it use the hover throttle percentage instead.
Any further suggestions on how to improve the tuning from here would be a huge help. Thanks again for your time!
I also wanted to know how to set MOT_THR_EXP value for T-MOTOR Alpha 60A ESC, 6007 II motor and 20" prop. It is a FOC based ESC and I read somewhere that for FOC based ESCs the profile will be linear. Currently it is set to 0.75 which is slightly more than recommended value of 0.65.