Improving Copter current limiting

ArduCopter Copter 3.4
1

Hello,

Someone can explain how work current limiting in AC3.4.4 ?
MOT_CURR_MAX ?

In copter wiki:
This protection automatically drops the throttle to as low as 60% of full throttle in order to limit the current requested from the battery.

This protection can drop throttle at 60%, no 55%, that’s it?

So if I want that protection dro below 60% for over powered drone, you confirm that I can reduce it with MOT_PWM_MAX param?

Also, how does it work:
If current overshot MOT_CURR_MAX, this feature reduce throut max to 60%?
or
If current overshoot MOT_CURR_MAX, this feature gradual reduce throut max, Without ever falling below 60% ?

2

That’s not exactly accurate. The lower it will go is hover throttle + 20% of the available throttle above hover throttle. So:

  • if your hover throttle is 0.5, it will go as low as 60% (0.5 + (1 - 0.5) * 0.2)
  • if your hover throttle is 0.3, it will go as low as 44% (0.3 + (1 - 0.3) * 0.2)

And yes, it will gradually reduce the maximum available throttle, not an instant cut to the lowest.

3

2017-02-14 16-26-44.zip (2.7 MB)
Thank you for your explanation.

You will find attached log of flight with :
MOT BATT CURR MAX set to 35A
MOT BATT CURR TC set to 0

Could you please help me to show action of current limiting on theses logs?

Thank you.

4

current limiting.jpg1342×354 99.1 KB

I found,

Here we see action off current limiting.

Issue, is as soon as current drop below CURR_MAX param, throttle was fully released, and curr max is re Ajouter au dictionnaire…

It will be great to make that current limiting be able to learn max trottle out for reduce this overshooting alternance ?