Bad Twitching, how to diagnose?

It’s not Mission Planner messing anything up. It depends on the orientation of the FC and the ESC’s. This is a common configuration that’s easily solved. Arducopter has several different FRAME_TYPE’s that can often handle this or you can configure manually as @uneasy has done.

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Before you try to fly it again, I would run it one time with the props upside down on the table and then look at the logs, just to check that it will not happen again! If you don’t want to do it, it’s okay, just try to fly it directly if you prefer!

That’s a good shout.

I thought everything is right, so I did one more flight, but it seems like 2 motors are affected now. didnt crash it this time, but was close.
It started very very nice, for a moment I thought that’s all sorted, switched to Loiter mode and it was holding position nicely and it started twitching again.

Other thing I’ve noticed, when I switch to Loiter mode, all of the sudden it started drifting and I couldn’t control it, I had to switch it to stabilize mode.
I am out of ideas now.

Here is flight log

Looks like I might have faulty motor, it doesn’t sound good compared to others. That;s the motor number 4

I’ve also forgot that I have ESC telemetry (forgot to switch it on after flash)
Here is flight with ESC logs

there was couple of small twitches and 1 bigger just before last landing. I am struggling to read those graphs and get something out of it, but for me it looks like ESC are behaving right so twitch would be on the motor itself ? or I am wrong ?

That motor doesn’t sound very good, it seems like it’s shaking or it’s desbalanced

I took it apart but can’t see anything wrong, probably bearing or shaft bend.

I will get 920kv recommended for f450 dji, hopefully that will be a fix.

Try moving your receiver antennas around and see if twitching reduces.

Why does that matter? There is no losing signal in this case! We checked the logs and it’s something with the motor or ESC probably

I’ve changed motors to 980kv, but twitching is still there and other thing that happens now, is even when it;s on the ground but I am adding throttle, front lifts more than rear and it drifts straight away after lifting. Not sure why is that.
But yeah … twitching … 2021-04-02 (542.0 KB)

Only idea I have now is to switch ESC with other ones to see if it follows.

Consider changing the ESCs to something well known, BLHELI32.
Are you sure there’s no mixing set up in the transmitter? sometime it looks like both pitch and roll do exactly the same movement by the same amount, at exactly the same time…
You dont get acceptable GPS fix until half way through the session - set these to ensure you cant lift off until there’s a 3D fix and Home can be set:
FENCE_ALT_MAX,120 <- set for safety and local laws
FENCE_RADIUS,600 <- set for safety and local laws
Yes you can stand around waiting, but then at least you know GPS is working as expected. This could help your take-off problems.
In MissionPlanner, press Alt A and accept all the battery settings then set this too: BATT_FS_CRT_ACT,1

It was my bad, drifting was that I had to calibrate Accelerometer again, it looks fine now.

I do have BLHELI32 ESCs - Tekko32 35A BLHeli_32

I have turned off FENCE just for now for tests, but I am aware of that.
I definitely don’t have pitch and roll mixed together :wink: that would be very noticeable during flight.

I will set BATT_FS_CRT_ACT to 1 or 2, once I am happy with hardware. I am not doing proper flights just yet, due to my “twitching” problem

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Well I think I have my answer, I swapped ESCs around and it followed the “bad” ESC. It flys normally for about a minute and then starts twitching. I guess that will be it. Now time to get new ESC. Well this one was new

What are your ESC blheli settings? Although if all but one work ok you would expect the settings to be good.

I think I didn’t change anything in them, I did connect with configuration software, unless I’ve changed something accidently ? but that would be a weird case. I’ve already ordered new ones, they are not that expensive.
Also I think if it was setting, it would be like this from very beginning of the flight, but it’s always after about a minute, (temperature ?)

just out of interests, here is the log, I was hovering 30cm above the ground and just at the end and it1980-01-12 (578.3 KB) twitched and dropped me to the ground

Also what’s weird. ESC voltage

I have capacitor on input … maybe that is causing it ?

So yeah clearly something wrong with that one ESC

without capacitor not better, but I guess we have a clear winner - ESC
Below is the voltage from ESC0 and ESC2 (faulty)

Are the cables from the power distribution board to the ESC soldered correctly?

Like I mentioned before, I swapped ESC around and it followed ESC not wiring

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I give up. I got new ESC. Changed it and it looked like it’s working now. but then all of the sudden I got 2 twitches that put me on the ground (luckily I was just above the ground then).

What is happening… it;s not wires, because wires stayed on old place when I swapped ESC around.
It’s new ESC and different motors.
I really don’t understand anymore

Here is Voltage graph from ESCs Red is the new one …