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tsquaremedia

18L Shakes!!!

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1 hour ago, Dylan Weidman said:

so I think I figured mine out. I ride hard too and have 3000 miles on this wheel. Turns out the plastic mold that mounts the case to the pedal arms finally fractured away from the case. basically my wheel and my case were barley held together causing the board to freak out. check for fractures to rule this out if you ride hard

I double checked and there is no fractures on my case. 

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On 7/11/2019 at 3:30 AM, tsquaremedia said:

So I ran into an issue today with my Kingsong 18L and hope someone can help me out. As soon as I get on the unit and start riding, it shakes violently until I get off and then it resets itself.

Just a little backgorund, the unit has over 2200kms. I'm a pretty aggressive rider, cruising speed of 43-45km, jumping curbs and riding down stairs quite frequently.

I already opened the unit to see if there was any issues with the control board, loose axle bolts, etc but didn't see anything that caused for concern. Do you think it could be a motor problem, control board or firmware issue? I am running the latest 1.13 firmware.

 

 

IMG_0172.JPG

1. Check horizontal calibration when upgrade firmware

2. check whether this happen when the wheel is still, e.g. lift up the handle and push forward or backward to see whether it shakes.

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5 hours ago, Micheal Shen said:

1. Check horizontal calibration when upgrade firmware

2. check whether this happen when the wheel is still, e.g. lift up the handle and push forward or backward to see whether it shakes.

I already performed a calibration and it still has the shakes. 

The wheel does not shake when still or when I’m trolleying it around. It only shakes when there is pressure applied to the pedals or to the front/back end of the wheel with my hands. You can see in the video examples I posted earlier. 

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17 hours ago, Marty Backe said:

Can you please try an experiment with your ACM. Get up to 40km/h and then pull the hall sensor cable and tell us what happens.

If what you say is correct, I'd love to know at what speed they stop being used.

But I have my doubts that this is a true statement. @esaj, do you know anything about this?

There are so-called "sensorless" motor driving algorithms that rely on the voltage and phase current measurements to timing the motor drive, but I don't know much about the details of motor control algorithms or if such is  used in any wheel:

Quote

Sensorless control (see Sensorless FOC Block Diagram) of AC drives is attractive for cost and reliability considerations. Sensorless control requires derivation of rotor speed information from measured stator voltage and currents in combination with open-loop estimators or closed-loop observers.

All I remember is reading somewhere is that it's pretty hard to get right because of the precise timing requirements on the voltage measurement, and as usual with complex motor algorithms, the math gets somewhat hairy fast... 

Might be able to test by doing what you suggest, using some sort of a jig to hold the tire off the ground with the mainboard visible, speed it up to high speed by gently tilting and then yanking off the hall-sensor -connector, but I doubt anyone really wants to try that  ;)  For science? :P 

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1 hour ago, Eliran said:

Mine is brand new, out of the box, and it happens the same shaking. VERY DISAPPOINTED!

 

Wow, thats not good! Hope you get a new replacement.

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Re reading the topic, I think I will open it disassemble it and reassemble it all over again. 

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