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Is this kogging and jitter in low rpms expected?

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Snabelost
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Is this kogging and jitter in low rpms expected?

Hello,

Im working on my dual boat motor for my fishing boat. Yesterday I connected the motors for the first time. The motors in Flipsky 65111 and ESC is FLIPSKY Mini FSESC6.7 PRO 70A.

I have run the FOC wizard and it detect the motor and everything is working. However at low RPM the motor runs pretty hard and it is impossible to run it at low rpms. See the video:

https://youtu.be/z02HhbUDVr0

Is this expected or can I adjust anything?

/Magnus

Snabelost
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Here is the motor specs:
 

  • Voltage range: 8-12S (33.6-50.4V)
  • Max power: 3000W; Continuous power: 1500W
  • Peak current: 70A; Continuous current: 30A
  • Motor KV: 160KV
  • Max spin speed(RPM): 8064
  • Size: OD65*L111mm
  • Shaft diameter: 10mm
  • Motor pole: 6pcs; 3 pairs
  • Motor stator slot: 12
  • Waterproof rate: IP68
  • Lead wires extension: 12AWGx1500mm

The ESC is this one: https://flipsky.net/collections/electronic-products/products/flipsky-min...

 

Snabelost
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I might have found the problem. HFI is not enabled. Will test tonite.

Snabelost
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HFI didn't make any difference except for a whining sound. However, if I switch to BDLC the motor runs a bit smoother.

What should I do to fix this or should it be this way? When i start the motor using like 0,15 duty it cannot decide in which direction it should turn. I kogs back and forth a few times before it runs.

Snabelost
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Now I have tried everything basically. Last step was to remove the propeller and run identification again. I got a little bit different results, but it's still the same. The motor is "misfiring" in different RPM's.

VESC is updated. It runs better in BLDC-mode than in FOC-mode. HFI doesnt make a difference.

What can I do or test?

I can add that I have two VESC and two motors and both are the same.

Rick van der Sloot
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Also first time user of VESC.

What control type are you using?

PID Speed Control?

Try a Current or Duty cycle control, most likely you want to use one these controls in the end.

For PID speed Control, I suspect you have to do some tuning on the Kp, Ki and Kd values, bust most likely it will already help if 'allow breaking' to false.

My experience so far it is difficult to get a decent Speed Control set up when the motor is unloaded.

HFI stands for High Frequency Injection, the whining is the  High Frequency part you hear at startup and low speed.

With the Beta/Test firmware you can also select silent versions of HFI, which eliminates the whine.

 

Rick

drummerboy5408
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First and foremost...what type (if any) of sensors are you using for the Startup? Hall sensors? Encoder? If you are not using sensors or have it disabled...you will need to tweak "Sensorless" FOC settings in the Tool.
Second, as mentioned above, Usually you want to start tuning with either Duty or Current control before tuning PID Speed Control. That way you aren't trying to diagnose around multiple PID loops.

Third, HFI is something that takes a LOT of tuning to work properly. You need to watch Benjamin and Franks HFI tuning videos before you even attempt it, because every motor is different and requires a different HFI recipe.

drummerboy5408
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Also, as mentioned by Rick above...You really need to tune the motors with the proper "Everyday" LOAD on the motors...meaning In water. If you tune the motors with the props in Air, you will most likely need to change the Startup parameters once in Water.

Snabelost
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Thanks for your replys!! I will read them thoroughly when I am in my workshop tomorrow.