I just built a new hex using 13X4.7 props, 1000kv 2820 BP motors and dual 5000 3s 40C batteries. Total weight comes in just under 4kg with my dslr. It flies pretty solid but I've noticed a lot of throttle management needed to keep it from "bouncing". It swings up and down in stabilize, alt hold and loiter modes. Loiter mode holds really well except for altitude swings. Stabilize and Alt Hold indoors (no wind) swings up and down too. I've been playing with ch. 6 tuning - tuning throttle kp but I can't seem to find the sweet spot. Currently I've got tuning (throttle kp) set with min of 0.1 and a max of 1. I is at 0.1, D at .001 and IMAX at 180. Since my hex is pretty heavy, should I be setting a higher throttle P? Should I also increase my IMAX. I'm a little uncertain and would love some guidance! Thanks in advance!
Another thought...my rate p is at .090. Should I take this value even lower?
you might want to go down on prop size. found this info.
Manufacturer recommends a 11 x 6 prop on 3-cells and 10 x 7 prop on 4 cells. We
suggest propping for around 480 watts continuous.
I will definitely go to 11X5.5 prop and 4s batteries. The reason i went with the 13X4.7 props is I don't have any 4s batteries and I had the 13X4.7 props!!!
Can you share a flash log of your quad doing alt hold? I could then tune the sim to match with these gains, then run a learning algorithm and spit out some new gains for you.
My first guess is your rate_I is too high and causing the oscillation. You have .1, where the default is .03
That can cause overshoot and if the gain is too high it will diverge.
It's been raining so these logs are quick and indoors so I'm not sure you'll be able to make sense of them. If not I will definitely get better logs this weekend. Thanks Jason!
If it's "bouncing" in stabilize, then I think you have some other issue other than Alt_Hold PID tuning, because Alt_Hold is completely inactive in Stab mode.
I was leaning more towards that idea as well. Just wasn't sure and wanted more of an expert opinion. I will give 11X5.5 props a try with some 4s batteries.
Finally got my new props and batteries. I went with 12x3.8SF and also testing out 11x5.5E APC props. I also went with 4s 5000mah 30c batteries. Still coming in under 4kg. Still need some tuning but I must say I'm pretty happy with how it's flying. You can't tell by the video but it's pretty stable. It did not complete the missions in the same way each time but it did complete the missions . You can see the simple mission I created in the video's bottom right corner. WARNING, my video is shaky from a broken gimbal. I wasn't going to let that stop me from getting some kind of video though.