Welcome to PhantomPilots.com

Sign up for a weekly email of the latest drone news & information

Purpose & effect of "GAIN" settings in the Assistant??

Discussion in 'General Discussion' started by PhantomFan, Nov 11, 2013.

  1. PhantomFan

    Joined:
    Oct 13, 2013
    Messages:
    408
    Likes Received:
    2
    Location:
    New York, USA
    OK folks...I've really made an effort to figure out the purpose and effects of the gain settings in the DJI NAZAM Assistant software through experimentation and reading, but I just can't seem to grasp the meaning from the manual, nor appreciate any meanigful differences by dropping the recommended 15% between each flight.

    The reason I'd like to understand the purpose and effects better is that I find I'm using only a tiny fraction of my stick throw in the course of piloting my Phantom. Consequently truly precise control eludes me since the stick movements are so fine. This is particularly true in pitch, where only the most imperceptible stick inputs are required to send my bird flying forward at unnecessarily fast speeds. I run out of room fast in my yard.

    So...do I dial the gain way down (like 60% or so) in that axis? I already dropped it to 100%, IIRC.

    Just what effect is the gain SUPPOSED to have on the operation of the Phantom??

    PF
     
  2. Studiowise

    Joined:
    Oct 22, 2013
    Messages:
    273
    Likes Received:
    0
    Location:
    Bristol U.K
    im watching this post with interest, i cant find enough info either and i hate having buttons or functions that i either cant use (S2 switch on my vision) or cant implement (settings in Assistant software)
     
  3. PhantomFan

    Joined:
    Oct 13, 2013
    Messages:
    408
    Likes Received:
    2
    Location:
    New York, USA
    I imagine a lot of folks would be interested in a fuller understanding of the gain function. Hopefully some Phantom guru will ring in on the topic and clear it up once and for all.

    PF
     
  4. Buk

    Buk

    Joined:
    Feb 28, 2013
    Messages:
    657
    Likes Received:
    29
    Location:
    Iowa, United States
    I don't know. That being said, I would like to hazard a guess.

    The relationship of input to output is proportional.
    Movement on a stick being the input and wattage being the output from the ESC to the motor.
    At a given gain setting, movement A to B on the stick results in output X
    Changing the gain, movement A to B on the stick results in output X plus some additional amount or minus some additional amount.
    Changing the gain, changes the proportional relationship. Greater or lessor response to the input.
    Changing the gain, changes the speed with which the full speed of the motors (response) is reached.

    Adding weight (gimbal, camera, FPV) slows response. Changing gain, increases response, to improve control lost due to increased weight. Maximum output is not changed by modifying gain, only the speed of which that maximum is obtained. In the same fashion, a too quick response will result in hunting (finding that sweet spot by searching too often and too fast).

    Just a guess. Now someone tell us what it really is. Thanks,
     
  5. PhantomFan

    Joined:
    Oct 13, 2013
    Messages:
    408
    Likes Received:
    2
    Location:
    New York, USA
    Well, that sounds like as good an explanation as ever I heard. I can only tell you that after an "extreme" experiment, I'm even more confused than ever. I dumped the pitch gain down to 40% (30% is the lowest allowable limit) and it seemed to have no effect at all to the response of the Phantom to Tx stick pitch inputs. Small stick inputs still resulted in what seemed to be the same forward motion of the copter.

    What DID seem to happen is that the Phantom's own attempts at recovering its attitude from disturbances caused by wind buffeting (zero stick input) was very twitchy, characterized by multiple fast corrections/over-corrections. Huh...<shrugs shoulders>

    I immediately restored all default settings and it flew in a stable, predictable manner and the hover corrections were much smoother. Go figure!

    I'd like to repeat this experiment when it is far less windy to be able to draw a more firm conclusion. I just don't get it. I'd have been very happy if the reduction in gain seemed to desensitize the Phantom to my pitch control inputs as logic would seem to dictate.

    Still waiting on an authority to tell us what is what, but my belief is that those values are for the Phantom's own "internal" use whose inputs are to be adjusted based on user observations on the need for sensitivity adjustments. The gain function does NOT appear to be a control function which varies the bird's response to the transmitter. I conclude this solely on the basis of experiment. It would be good if someone has actual knowledge on this topic. What I have suggested is merely surmise based on one experiment.

    PF
     
  6. ElGuano

    Joined:
    Sep 4, 2013
    Messages:
    2,219
    Likes Received:
    4
    If you're looking to dampen the effect of the sticks, you want to adjust "Attitude Gains" - pitch and roll. This dampens the stick input. I run about 80% to smooth out my movements/corrections while videoing. The downside of course is that the Phantom doesn't respond quite as quickly if you need to pull it back from an obstacle or gust of wind. And you can't adjust the stick gains for the left stick (throttle and yaw).
     
  7. Buk

    Buk

    Joined:
    Feb 28, 2013
    Messages:
    657
    Likes Received:
    29
    Location:
    Iowa, United States
    Perhaps you are correct. The gains change the proportional control the Phantom exhibits for itself. Changing the gains modify how the controller makes adjustment. The owner/operator may see the Phantom making corrections and either rapid hunting for control or lacking or slow response control and owner/operator changes gain to improve what they believe with correct erratic flight into stable flight.

    Stable flight would be modified by adding weight, losing weight, prop selection, motor power loss due to age (i.e. bearing wear) or the gamut of environmental factors (i.e. wind). Changing gains modifies the control parameters of automatic control.
     
  8. netphreak

    Joined:
    Sep 17, 2013
    Messages:
    228
    Likes Received:
    0