Odd behavior from ModalAI 4 in 1 ESC
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@Alex-Kushleyev the motor / prop combination is a mn4004 or mn4006 with a tmotor MS1101.
I switched over to the 138 ESC last night to see if the ESC board was just bad, but I'm still having similar issues.
Thanks again for the help!
Matt -
@Matthew-Wellner , remember we had a discussion about 5 months ago, where i helped with the tuning. At that time, did you get the setup to work? https://forum.modalai.com/topic/2979/can-you-power-voxl2-from-the-modalai-6s-esc/ . Did anything change since then in terms of your motor / propeller setup? did this issue suddenly start occurring without a hardware change? (any crashes that could have damaged the ESC?)
Also, is your motor a Tmotor MN4006 or SunnySky? Also, what KV and what voltage are you applying (4s / 6s). I do have these propellers.
Alex
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@Alex-Kushleyev sorry for the slow response. I never actually test flew the setup outside of a few quick lift offs because we were making some housing changes. I thought the platform just needed to be tuned.
I have run 3 different motors with similar behaviors - sunnysky 4004 (400kv), tmotor 4004 (400kv) and tmotor 4006 (380kv) all at 6s voltage with 11" props. I also tried 10" master airscrew props with the 4006s.
I swapped the 0134-6 ESC with a 0138 ESC yesterday after the the 0134-6 got hot enough that, I think, one of the motor wires desoldered itself.
Thanks again for the help!
Matt -
@Matthew-Wellner , thanks for the clarification. I do have the tmotor 4006 and sunysky motors, since i ordered it last time we had the discussion.
Lets take a look at the px4 log once you have a chance to share it. Thanks.
Alex
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@Alex-Kushleyev I'm sorry to have to ask this, but is there a way to upload the logs via this interface? When I try and upload a file I get a permissions error.
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@Matthew-Wellner , no problem, if you are ok sharing the log publicly, here is how we usually do it : upload it here https://review.px4.io/ and send a link. from there i can inspect and download the log for further analysis.
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@Alex-Kushleyev Is there a way to share it privately? Otherwise I can send it to the link you already shared.
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@Matthew-Wellner , i will reach out to you via email
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@Alex-Kushleyev thanks! I responded. The ESC parameters file were exactly as you example except for the calibration parameters (the 3 numbers we need from the calibration routine). I averaged the numbers I collected from running the calibration on each ESC.
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@Matthew-Wellner , As we discussed offline, I am going to post the summary for the likely issue here:
By setting "demag_timing: 1" in esc params, it enabled some experimental feature, which fails to work correctly above certain rpm. It prevents motor from spinning faster when more power is applied (above a certain rpm). You can see from plots above, the desired command for motor 4 (purple) goes higher, but actual rpm is flat lined around 5700rpm (black). Also the current jumps up significantly for motor 4 (black) when it hits that ceiling.
For your motor, please disable this "feature" by setting demag_timing to 0. Depending on your current timing advance, we may keep that the same or increase slightly.
After disabling demag_timing-> 0, i would recommend performing rpm step tests to make sure the de-syncs still do not happen.
I am sorry about this, I will update documentation to not recommend using this feature.
zoomed in
Alex
