Wobbles 35+ kmh on trampa board

#1

Hey guys ive had this issue for a while now like a few weeks and i cant figure out what it is. i jsut replaced relativly new bearings with a fresh set and replaced the rear dampas and bushings. i still get wobbles past 35+kmh only when accelerting going down hill without acceleration is perfectly fine 40+kmh no wobbles i cant figure it out for the life of me. i have managed to get to 40kmh by creeping the throttle up ever so slightly.

12s7p esk8 192kv motors etox Maxi drive 6.25 ratio helical gears,
Vesc 6 and vesc MK3

1 motor ,running HFI and the other running hall

just replaced rear wheels and tubes today still same

anyone have any idea whats going on here?

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#2

Is everything on your drivetrain secured + tight? Wheels balanced?

#3

just replaced the rear wheels + Tubes so they are brand new, the issue is only when accelerating when im going 35 then roll down hill i can easily hit 40+ no issues no wobbles. it only happens when accelerating.

#4

Check this thread, because it only occurs while accelerating this might be vesc/firmware related aswell.

3 Likes
#5

thanks ill read into it i really want it fixed! spent so much on replacing parts i thoguth were damaged its getting rediculous now.

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#6

Check this out, there are known issues with the vesc firmware that causes speed wobbles at higher speeds.

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#7

hopefully their is a simple solutiuon to it thanks guys.

1 Like
#8

hmm sadly i dont have any other firmware versions to downgrade too. i tried searching for an hour sunday but couldnt find where to download them from. anyone got any links?

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#9

Vesc tool backups from @rpasichnyk

And here are some version backups from @pookybear
https://drive.google.com/open?id=1mE_9zqmv7WPevKKG8KccF4fGCY9Qpj7S

2 Likes
#10

thanks i just set the T:1000uS value on the hall sensor on the 4.1 version is it worth testing out or just downgrade to a lower fw?
im running the Wand so this might effect what i can use?

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#11

In that case it might be worth to try with the adjusted T value on 4.1. Maybe @rich @Trampa can help further from here

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#12

going to do a test ride i changed the value down to 1k, but i am running one motor in HFI mode so not sure how much this effects it too

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#13

well it fixed the issue but now i have another 2…

  1. i get a loud screeching sound from the back of my board on startup
  2. i lost just about all of my torque

my brakes work fine, but it has never screeched like this before. all iahd done was set this

image
image1649×869 33 KB

i might try running both sensorless tomorrow as it is quite late here. at least i know its firmware related now and not hardware related so thats somewhat a good sign i guess…

#14

Hfi enabled?

#15

on the vesc 6 it is but never made that sound before not that loud either. i only adjusted the MK3 since it is the one with working hall sensor

Going to downgrade vesc tool to 1.28 since it has support for the wand. and flash 3.65 FW on both vesc 6 and MK3

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#16

Do you have a video of that screeching sound?

#17

i dont unfortunatly its fairly late now as its 9.45pm. i can take a video of it tomorrow night after work or before i leave around 8.30 in the morning and post it here. it is quite loud.

#18


Is it that sound? Go to that post and watch the video.

#19

nope that is normal i know from the HFI mode, it was a literal screeching sound. ill take a video of it in the morning while its on the bench.

#20

My guess regarding the sound is this?

although its only on the foc detection

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