Throttle and axisPID[PITCH]

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Throttle and axisPID[PITCH]

Postby copterrichie » Mon Mar 04, 2013 6:45 pm

I do not know if this is a bug but it is driving me nuts. With the copter sitting perfectly level on my work bench and no motors running, if I increase the throttle to 1600+ in the GUI, the axisPID[PITCH] value goes from -30 to -126.

I added axisPID[PITCH] to debug[2] to the Mix table.
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Re: Throttle and axisPID[PITCH]

Postby copterrichie » Mon Mar 04, 2013 6:54 pm

I should also mention, this is when I have ANGLE mode enabled but I am sure it happens in HORIZON and ACRO modes as well.
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Re: Throttle and axisPID[PITCH]

Postby copterrichie » Mon Mar 04, 2013 7:14 pm

Although this is my VTOL, this problem has nothing to do with the Mixing table itself. It is the value placed into the axis[PITCH].

http://youtu.be/YNHPaYbOcNA
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Re: Throttle and axisPID[PITCH]

Postby PatrikE » Mon Mar 04, 2013 7:29 pm

In Multiwii.ino
Code: Select all
  #define BREAKPOINT 1500
  // PITCH & ROLL only dynamic PID adjustemnt,  depending on throttle value
  if (rcData[THROTTLE]<BREAKPOINT) {
    prop2 = 100;
  } else {
    if (rcData[THROTTLE]<2000) {
      prop2 = 100 - (uint16_t)conf.dynThrPID*(rcData[THROTTLE]-BREAKPOINT)/(2000-BREAKPOINT);
    } else {
      prop2 = 100 - conf.dynThrPID;
    }
  }

It's dynamicly lowering the PID's when you use much throttle.
Great if you have oscilations when you pull full throttle runs.
Especially on airplanes.
Set TPA in Gui to zero and it should be disabled.
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Location: Sweden

Re: Throttle and axisPID[PITCH]

Postby copterrichie » Mon Mar 04, 2013 7:33 pm

Thank you, you hit the nail directly on the head. I just did a EEPROM clear and the problem appears to be fixed on the bench. Seems when going from one firmware version to another even if they are minor changes, the EEPROM should be cleared.
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Re: Throttle and axisPID[PITCH]

Postby copterrichie » Mon Mar 04, 2013 7:47 pm

Eureka, Hooray, Bingo!!! That Damn Pitching Problem is GONE!!!
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