Weight Changes While in Flight

ArduCopter
1

Hello, during the flight, my quadcopter carries a 330 ml (11.16 fl oz) water bottle, but I leave the bottle halfway through the flight route.
My questions:

  1. PSC_ACCZ_I and PSC_ACCZ_P parameters are set according to MOT_THST_HOVER parameter. Will this cause a problem with the drone, should I set these parameters with the bottle present or not?
    With the bottle MOT_THST_HOVER=Around 19,.
    With no bottle MOT_THST_HOVER=Around 22,    .
  2. Should I set the PID settings while the bottle is present?
1 Like
2

Always tune for the lightest case. More mass will damp any oscillation.

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3

330ml wont be a significant weight unless this is a really small copter, but for major weight changes adjust these ACCEL params as per:
ATC_ACCEL_P_MAX x (min_TOW / max_TOW)
ATC_ACCEL_R_MAX x (min_TOW / max_TOW)
ATC_ACCEL_Y_MAX x (min_TOW / max_TOW)

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4

I guess I can’t set the min_TOW max_TOW as I will be leaving the bottle in flight.
Also I don’t know how to set these values based on weight.
I set these values with the help of this excel file.

prmtrler
prmtrler959Ă—452 15.8 KB

As I understand it, on the flight where I have to drop the bottle, I will set the values (PSC_ACCZ_I/PSC_ACCZ_P) as if the bottle is not there.
I will take the bottle into account on the flight where I do not leave the bottle.

5

You are doing it correctly.
If you add a significant payload just calculate new ACCEL values using your minimum (normal) take off weight divided by your new increased take off weight, multiplied by the original ACCEL value. or just guess and set ACCELL to about 2/3 or 3/4 of what it is now.
But 310ml should not worry you. With bigger payloads, in the KG range, you tend to want to AVOID dropping them :slight_smile: so setting new ACCEL values is not an issue.

1 Like
6

Thank you so much.
The only thing that confuses me is that I didn’t take the weight into account when setting the ACCEL values. Calculated with 12 inch propeller and 5s battery as seen in Excel.
I guess 330ml shouldn’t worry me? :), Thanks again