Motors speed oscilates during flight

Sir,

Normally roll and pitch value of P and I should be same. In your case that not seen same.

If you have done many changes than start from below.
Now you can start reset all values by Configuration - Full parameter list - then you will find “Reset to default” . Than you need set all thinks like Fram type, Campos, flight modes etc.

If you think, that you can set value proparly than no need reset all to default to save your time.

Please set roll and pitch value of P and I same at nearly 0.12

What I obser, if motor are higher kv like 2300kv P and I value can start set from lover value like 0.10 than rise by gradually to tune, like 0.105, 0.11, 0.115, 0.12 etc.
If motor are low kv than mostly set in 0.18 to 0.2

I think you are using higher kv motor, for good start you can set roll and pitch value 0.10, than gradually increase.

Sir, you can increase simply way from configuration - Basic tuning

From here you can set roll and pitch value in single click from “roll/pitch sensitivity” button. I think this is best and easy way of manual tuning.

Some tips according to my personal experience.
Do that tuning in Loiter mode, this mode control lot of thinks to avoid accident like altitude and position.
You can start from lover value of “roll/pitch sensitivity”
When you strat and obser vibration at 40 to 48 % throttle at groud level , than you need lover down “roll/pitch sensitivity” value, than again try at 40 to 48 % than if you find no vibration than rise throttle just above 50% than copter will lift smoothlly and may be not need further more tuning.

Please share result so we can think on other points

Good luck Sir.

Stabilize P…from 4.5 to 1. OK,
And try to fly in Wind.

Roll and pitch P and I are the same and standard! I resetted to default parameter before screenshot and did the wizard again.

I am not in the air yet. Just keeping the copter in my hand. It is not an condition I would start my copter in the air yet.

@ambattuhari
As I wrote before, I can’t change P from 4.5 to 1. MP will correct it to 3 as a minimum value.
For sure I wont try such a shaky copter in the air. It’s not moving slowly around one axis, but shaking maybe more in roll with a frequency of maybe 10 to 20Hz.

Sir if possible send video of your test flight, well please recheck motor sequence and propeller direction according to following figure.

Than you need test motor individualy by motor test, for that go Initial Setup - Optional Hardware - Motor Test

Keep in mind Motor are tested in a clockwise rotation starting at the front right.

Please do that , and share tour result with video.

If this is right than please Reset all to default as I suggested way.

set d gains to 0!!!

what size are your props?

Quad H 250mm
Motor 2306 27000KV
Props 5040
Pixhawk Arducopter 3.5.3
ESC HAKRC BLHeli_32 protocol normal (Oneshot125 testet as well)
4S 2200mAh

I flashed rover and later Copter again.
I run through wizzard
Made an ESC calibration and Motor test
reduced Mot_Spin_Arm from 0.1 to 0.05 and Mot_Spin_Min from 0.15 to 0.1

I feel like ist getting better, as I set all P to Minimum, but as some suggested I can not set those in first Row below 3.
So someone can explain how I can reduce them?
Is it a MP Limit to 3.0 or is it limited in the FW?
If it is just MP can I load a manually edited Parameter file to the pixhawk?
Maybe it should be changed in the next FW update for use with small overpowered copters.

Now with lowest P’s it seems like it works from time to time. But it’s maybe luck.
I tried to get it up in the air then, but recognized, that it starts Spinning.
Is it possible, that the external compass is the Problem?

Here are two Videos.

https://www.dropbox.com/sh/38uwv2jsakrztrl/AAATZNs0kIyl1tLretTbaMrUa?dl=0

Hi, I didn’t check this particular value, BUT, usually the limits are in Mission Planner. And usually the limits are not applied when you make changes to the full parameter list.
So, try changing atc_ang_pit_p and atc_ang_rll_p, in the full parameter list.

Hello Tommy Sir,

That very great that you minimized Arm spin, and minimum spin, but main think to use over power motor you need to minimize maximum spin of motor through MOT_SPIN_MAX
I think you can set maximum spin limit 70 percent by set MOT_SPIN_MAX = 0.7
When your copter fly normally, than you can set maximum spin in this way so that in stabiliz mode your copter Hover at 50 percent throttle.

This is pure solution of over power motor.

Sir actually no need to set stabilize P value that you are trying, 4.5 default value is correct , at least for your case because I am using over power motor like you.

Some key specification of my copter.

Motor - Emax 2306 2300kv (Max thrust is 2kg per motor)
Total weight of copter is only 800 gm
I set max spin only at 50 percent

I think my pid values may mostly mach you . . . If you think right than please test your copter and reault please.

Well you need to match/set same direction of compass with copter nose. If you dont have an idea to set direction of compass than you can ask same me.

If you think your external compass is not working proparly than you can use internal compass, but just insure that no heavy current cable near Flight Controller.

Sir, I just saw video of your copter, dont confuse, you are very near answer, copter vibrating dua to high value of P and I. And copter yawing because direction of compass is not same with direction of Flight controller means at nose.

Just set maximum spin limit of motor, set pid according to my provided image of pid, and set compass direction. This will be good start, once normally fly than you can set more accuratelly.

Waiting for result . . . . Good luck

@wicked1
In full parameter list you can enter values below the limit. Thanks.

@ypsonar
I really apreciate your big efford. Thanks.
I finally got rid of the oscillation. I limited the Mot_Spin_Max to 0.5
and also read some other articles about Arducopter and small overpowered copters.
As suggested there I increased the Filter frequency to 40Hz.

But the turning / yaw is still there. I believe it could me magnetic interference. But it’s same with internal and external compas, so I don’t know exactly.


I think it’s getting more yaw-torque when I increase throttle.
Unfortunately I don’t know how to view different charts with different value-axis. This Log-viewer isn’t that comfortable.

1 01.01.2000 01-13-02.bin (180.1 KB)

Now I don’t have much time, so I can continue my testing on tuesday.

It same problem after upgrade from 3.4.6 to 3.5.2, i reset setting default after upgrade, wizard, ESC calibrated

After test fight it to bad fly.

abnormal!!! Moter Test. When click Test all motor. only motor A spined

Now back to 3.4.6 it good.
I just try flash rover before Copter

I had the same Problem with Motor Tes All. If you test them one by one it should work.

I still won’t get it in the air right.
I changed position of the power cables to the ESCs, but still turning in circles. Even the external compass is far away from the power lines. 180mm stand off.

2 01.01.2000 01-20-56.bin (537.9 KB)

But for me it looks like the more current increases the more desired yaw is away from yaw.

Hi all,

If you have oscillations with the default pids you have to go through the process of doing a manual tune.

I will try to get something up that is a little clearer over the weekend here:
http://ardupilot.org/copter/docs/ac_rollpitchtuning.html

At last I got time to test my quad. Here is the part of graph:


One can see smooth input of channel 3 (blue color) an jittering output of channel 3 (yellow color).
And here is complete log file:
3 7. 12. 2017 22-23-16.zip (318.6 KB)

I though it appeared since version 3.5.x, but now I downgraded to version 3.4.6 and motor oscillations/jitter is still there.
Any suggestions? I’m bit annoyed, because I really don’t know what to do. I’m afraid of using any auto flight mode.

You will need to do a manual tune followed by autotune.

I think I found the ground of my oscillations: Mot_Spin_Max had set to something big (guess it was 0.98 or so). Yesterday I set it to 0.85 and Bob’s your uncle :wink:
I didn’t do real flight yet because have no time to go to field, but in the room I started motors like the quad is going to almost take off, and the run of motors was smooth :-).
I think overpowered copters have just this problem (as ypsonar mentioned) and it is little bit miserable because I can’t use whole potential of motors - e.g. when I would need fast climbing. Is there a way to let the Mot_Spin_Max in full range (e.g. up to 0.98) and play with some PID parameter to get rid of oscillations?

@Leonardthall: manual tuning seems painful to me, I would rather do it by setting some PID param to get quad flyable in stab mode and then run autotune and of course with Mot_Spin_Max set to high value (0.98).