Hi guys.

I have watched a lot of videos about PID tuning. I am thinking of trying to tune my quad because I think I have some propwash.
If I let the quad fall and try to level it gently with throttle I can see vibrations until it is level. I guess this is propwash.?
My build is a voladror II vd5 with dji o3 and 1950 2207 motors.

I will follow the instructions on this video


I will mess with the filters first before getting into the actual tune itself. So I will try the recommendation of the video about a single D term filter 80-110hz.

I just did the first part with a few throttle punches gradually and checked the log files and saw that my vibration logs are at lower frequencies. I see that they are overlapping the Low cut filter.

So if I set the single D term filter and is not working as it should, what symptoms will I experience? Since I am new into FPV I don't know what I should expect etc.

Here are my gyro scaled logs

Even with tuning you will never be able to get rid of prop wash if you are dropping down vertically directly into the dirty air under your props. You can tune out some of it if it happens while flying forward and down, but not from a straight vertical drop, so if that is the scenario when you are getting vibrations and wobbles, the best solution is to just learn to fly your quad without dropping it down into the dirty air.

Thank you for your input.
Ok so I will avoid that.

So I started trying some tuning guys.

I set the filter as I said at single D term at 90-110hz BIQUAD.
I set I slider and FF slider to 0.
I use Angle mode to hover and rock the pitch and roll axis to tune the P-I slider.

I notice that the yaw drifts a little to one side. Even if I just hover the quad to hover it drifts the yaw axis slowly.

Also I notice that when I have connected the FC to betaflight and have the quad on my desk stationary without any movement, the heading degrees drift over time too. It starts at 0 and then goes 359-358-357 etc. Without moving the quad at all. This is happening without the transmitter being connected to the quad.

Is this normal? Do I need to check for something?

(02-Oct-2023, 09:54 AM)jimskeet2002 Wrote: Also I notice that when I have connected the FC to betaflight and have the quad on my desk stationary without any movement, the heading degrees drift over time too. It starts at 0 and then goes 359-358-357 etc. Without moving the quad at all. This is happening without the transmitter being connected to the quad.

Is this normal? Do I need to check for something?

Myabe obvois but you didn't write it so... did you try calibrating the accelerometer?

(02-Oct-2023, 01:47 PM)Mike C Wrote: Myabe obvois but you didn't write it so... did you try calibrating the accelerometer?

Yeah it is calibrated.
I think the reason was some wind gusts that affected it.

I managed to tune it good and after resetting the I term it didn't drift any more when I was flying it.

The YAW heading in betaflight is doing it since always.

If you have yaw drift, you might check your BF receiver tab. The yaw channel should be properly centered (1500 by default), otherwise if your radio or FC is set to a different value then will see continuous slow yawing.

… you said you want to try pid tuning because you THINK you have prop wash…
I can honestly say, I have year to tune a quad using pids… RATES yes,…profiles YES, sliders. Yes…
I don’t fly as much as I like, but I know what hitting a turn hard and “feel” the quad kinda loose it.. I just learn what that quads “limit” is…
I can say when betaflight (4.3 I think) had “profiles” (race, cinematic, freestyle-Bardwell did a review)… I followed his lead.. and that quad flew incredible…
I have heard of “over tuning”.. where you quad is “dialed in” perfect… but chip, bend a prop and the perfect tune can cause failure…
Give it a shot..

I managed to get the step response graph as it should be. I tried how it flies today and it was a lot better in prop wash. Huge improvement.

I used this same video for my tune. First fly defaults pids and filter. Quick flight throttle ramps. Test the noise. Then do your filters. If you can turn off gyro filters. My quad at first had some noise but after new props that noise went wayyyyy down. I had issue with prop flutter at full throttle but was also fixed with new props. The only thing I did diff than Chris rossers video was that instead of starting moving the PI slider, I found better results by moving the D slider first. According to step response when D slider was at 1 the PI slider needed to be at 1.3-1.4, but it wouldn’t be a clean line it would bounce back. I couldn’t get it right. So I went back default then started this time moving the d slider. I found at .8 D slider with 1 on the PI was PERFECT. I couldn’t get that with moving the PI one like he did. Also the master multiplier didn’t do much besides cause overshoot and oscillations in my quad least. Left at 1. I was actually really surprised how I went thru and found the defaults were actually almost spot on. Don’t fix something that ain’t broke ya know. Good luck to ya on tuning. Idk much but I’ve been watching and reading and playing with my tune I think I got a good hang on it. But lemme tell you a lot problems came from props. Mine were even bad but had some curling at the tips. Made a lot noise. Take care mechanical issue first. Then use defaults and get your filters right. Then tune. Don’t go crazy and to aggressive bc the props can get slightly bent and cause hell.