Tutorial Arduino: noisy motors while not moving? Check this out.

Hi
Again I want to help any members here by sharing the knowledge given to me, if you have similar issues: noisy motors while they are not moving. Although I am very familiar using the Arduino I was wondering all the last months why my motors are so noisy while they did not move. I had never the time to dig deeper into the source of that annoying "feature", until @RacingMat had coded and linked a new code for the Arduino "Utrasonic" which gave me the input to fiddle it out.
While I am using SMC3 due to the nice utility and myself approved code I asked @RufusDufus about any details of his Arduino code, which sends 20kHz PWM and higher (instead of standard 490Hz PWM - thanks @RacingMat for that) to reduce the noise.
He explained, that
"two parameters in SMC3 that are most likely to cause noise in the motor windings (buzzing or humming type noise) are the Kd and PWMmin values. This type of noise is most noticeable when the motors are holding position and not moving. If the noise you are getting is mostly when moving (unless slow smooth movement) it is probably not from the PID".
So far we know from where we expect the source of the noise. But what can we do?
His response so far:
"Kd values cause the PWM duty cycle to rapidly change positive to negative as the system tries to compensate for errors. This can create harmonics in the windings causing noise. There are two ways to minimise this
1. use a very small Kd value (0 completely eliminates these effects - but results in no damping effect)
2. Increase Fpid, this is a divider that reduces how often the Kd parameter will update the PWM calculation - specifically added to help combat motor noise.
PWMmin values has a similar effect because when the PWM drive changes direction it is not a smooth transition as the PWM duty ramps down to zero then raps up in the other direction. It ramps down to the PWMmin and then jumps to PWMmin in the other direction. So you get a stronger drive but potentially with more motor noise.
Thanks a lot @RufusDufus for detailed explanation, I hope adding this knowledge should reduce any further support in future if this issue will be discussed.
BTW my SMC values are for the
Seat (two 750W motors):
Fpid / 2
Kp = 500
Ki = 0
Kd = 0
Ks = 1
Fpwm = 20kHz
PWMmin =0
PWMmax = 200
PWMrev = 190
Max Limits = 110
Clip Input = 180
Deadzone = 0
Traction loss (one 200W motor):
Fpid / 2
Kp = 500
Ki = 0
Kd = 0
Ks = 1
Fpwm = 20kHz
PWMmin =0
PWMmax = 205
PWMrev = 200
Max Limits = 20
Clip Input = 150
Deadzone = 0
Settings shared by @RufusDufus
Fpid / 4
Kp = 700
Ki = 0
Kd = 80
Ks = 10
Fpwm = 20kHz
PWMmin =0
PWMmax = 220
PWMrev = 210
Max Limits = 20
Clip Input = 150
Deadzone = 0
Many thanks to @RufusDufus again for the time he has taken.

thanks for taking the time for sharing this information/explanation.

Is it sounds like knock from time to time?

no, this is normal and usually happens.

Hello,
thanks for your explantation. I understand where the noise comes from, but can this damage the Motors? The reason I'm asking is, I have tuned my PID settings again at the weekend. Now they are very aggressive and I like this settings much. But sometimes there is the noise when motors are holding the position. As I'm happy with this settings and waering a headset while gaming I can't hear the noise. So I would let my settings as they are, but i don't know if this can damage the motors for time.

Motors no, but reductor will wear

Pardon?

gears will wear if they are overloaded.

Hi, @Pit I tested those settings, my motor noisy will be better ,but as I shown in http://www.xsimulator.net/community/threads/arduino-noisy-motors-while-not-moving-why.7802/
It works sometimes quiet and sometimes noisy,Can u encountered this problem?

at least someone who knows that I am shortsighted... no need of my glasses any more Anyway I will have a look at this.

Are you hearing me????

I've likely read this all wrong, but are you using a cap on your feedback line to earth to get rid of noise?

I tested my project and I saw the same issue "noise"

Can be use the induction motor with magnetic stop?

maybe this noise caming from the brush motor, they can't hold the position well
without spend a lot of power and the accuracy to stop I think that some motor like "wiper or other gearbox" on the shaft have gap between the contact to brush is to big than when the motor trying hold this position don't have a good contact.

Thank for sharing.
Now My 2dof project is louder noise and not smooth.

So go back to former settings...

Low noise give less power but hight power has lounder and not smooth graph
Fpid / 1
Kp = 660
Ki = 0
Kd = 0
Ks = 60
Fpwm = 20kHz
PWMmin =0
PWMmax = 245
PWMrev = 240
Max Limits = 20
Clip Input = 150
Deadzone = 0

Hi,

1.Does this @RacinMat code will work for BTN8982??? In theory I found in datasheet that BTN8982 supports up to 20kHz but I do not know anything about electronics so I rely on you guys.
2. Is this code overwrite standard SMC.ide code? 3. Do I need to make changes in downloaded @RacingMat's note?

hi
I never used SMC sorry.

adjust Fpid / 1 ===> Fpid / 10

Hi,


Hi, I was able to lower the noise a little by playing with the settings. only I loaded a 40kg weight on it, and the noises started again. the problem is that in the end it's more than 150kg me with who will have to lift... in diy actuator e30-150 motors 750w mode, the gear ratio is not very strong..

here are my current settings my parameters for the smc3 utils:
Fpid: 7
Kp: 150
Ki: 15
Kd: 0
Ks: 30
Fpwm: 20kHz
Pwmmin: 0
pwmmax: 150
pwmrev:140
maxlimit: 215
clip in: 255
deadzone: 0