@awagner ,
I think the main issue that started the failure mode was the spin-up type was set to 0 in params, which I do see that you got from the seeker_v1 xml file you mentioned. It is not your fault. The non-sinusoidal spinup is not as reliable and it is mostly not used any more. I will look at removing the old param files that use that option.
Let me explain the reasoning behind using a larger ESC, especially during initial testing:
the larger (FPV) ESC can handle much larger currents and dissipate a lot more heat, so it can handle much larger glitches, which could arise from mis-configuration during initial testing
the ESC firmware does have some timeouts for protection, which generally do prevent fatal issues like this, but if the glitch results in enough current to quickly burn out a mosfet, the ESC cannot recover. The larger ESC (with larger mosfets and larger thermal mass will take longer to burn out, so the ESC's timeout / glitch detector should save it)
larger motors in general have larger stall current, which would result in large current if there is some glitch during start-up.
based on the numbers that you provided for the motor spec calculator (3.75A hover / 17A max), it should be possible to tune the mini ESC to work, however there are still some things to consider:
may need to add more bypass capacitance to handle larger current transients
if the motor is stalled (due to impact, etc), there is still a bit higher risk of ESC burning out due to stall detection being a bit too late.
As for the xml to use as a starting point.. You can start with this one:
https://gitlab.com/voxl-public/voxl-sdk/utilities/voxl-esc/-/blob/master/voxl-esc-params/D0020/m0138_3110_900kv_gemfan_10x4.5_tri.xml
This is tuned for a 6S application 3110-size 900kV motor with a 10x4.5 tri-blade motor (pretty powerful configuration). You will need to update:
voltage (6s to 4s)
motor params (kv, rpm curve, etc)
you can set the timing advance and sense advance from 20 to 0 (your application is likely not aggressive enough to require tweaking that), although you can do some bench testing to determine if you encounter de-syncs during large rpm transitions : https://gitlab.com/voxl-public/voxl-sdk/utilities/voxl-esc/-/blob/master/voxl-esc-tools/doc/low_kv_motor_tuning.md
you may need to adjust the spinup power / latch power -- generally keep it between 70-100 (7-10%) but when i tune this, i also usually find the minimum spin-up power that is able to reliably spin up the motor and then add a 10% extra (so 70->80). You can set spin-up power to a higher value in sinusoidal spin-up mode and it will produce a lot more torque, but will also consume more current. I usually try to limit a per motor spin-up current to 1-2 amps as a rule of thumb. for a fixed prop (not folding), your spin-up time can be anywhere between 500-1000ms, you can experiment. If you see the motor skipping during spinup and re-starting, you can increase either spin-up time or spinup power.
may want to re-enable start-up beeps (disabled in this config)
you can set kp (proportional gain) to 50 first (softer), then bump up to 100 or so, as you build confidence. higher kp will result in snappier response (faster than traditional ESCs without rpm control) but will also draw more current during transitions.
(with M0138, you should not need to add more bulk capacitance to ESC power).
With correctly tuned sinusoidal spin-up procedure, it should work pretty much 100% of the time (spin up on the first try every time). If you are seeing some inconsistent spin-up behavior, then it is possible there is some parameter issue and it needs to be investigated.
When you get your M0138, i suggest updating the params per my notes above and doing some bench testing using voxl-esc tools where you just spin up and stop motors many times in a row and make sure the spin-up is reliable.
Please let me know if you have any other questions!
Alex
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