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Adding a Openloop COMM Comand

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Sun, 2021-01-17 21:27
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JulianT
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Adding a Openloop COMM Comand

Hi all,

i am also trying to get an answer by putting this to another forum. But maybe my question is so silly, that it doesn t deserve an answer...

Is it possible to add a open loop comm command in the commands.c ? Like COMM_SET_OPEN_LOOP (Current, RPM)

As far as i know the open loop is already implemented and could be used in the new firmware in sensorless mode but i need it in sensored mode and i need to change the current value while running. To do this a UART command would be great.

I am building a 6 wheel car with 6 hub motors and the 6 esc s are controlled via uart / microcontroller. Turning at a point needs very high currents at low speed so it does not work with COMM_SET_RPM.  COMM_SET_POS works better but the movement is not smooth.

And a second question: is there an advantage for switching from sensored commutation to sensorless commutation at high speeds? (because of this feature in the VESC Tool)

Thx alot for an answer in advance and thx for this great project.

Kind regards

Julian Tacke

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Thu, 2021-02-04 10:30
MrShocko
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For UART control of FOC OPEN LOOP Refer to my comment in https://vesc-project.com/node/957

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Mon, 2021-02-15 12:17
JulianT
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Thanks alot for the answer and the workaround. But it still would be nice to have a direct Comm_Command.
The Answer to the second question would also be interesting... :-)
I had an idea that might be useful:
Temperature measurement via the internal DC resistance.
Advantage: You don't have to retrofit a temp sensor.
Disadvantage: only works when the engine is not running.
Because nearly every Motor has Copper windings and the change in resistance over temperature is more or less constant you just have to measure the resitance when you switch the ESC on or when you make the Setup. So when the motor is not turning the ESC can make a measurment again and than calculate the temperature. Of course it is not so accurate than a thermal probe but better than nothing.
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