[greggles77]

Hi all

Please see my video


When applying yaw in flight, the hex 300 dips and heads off in an almost random direction.

I would expect it to pivot on the spot to face whatever direction when hovering fairly stationary, which it does for very small movements, but anything more than a touch of yaw makes it lurch off in a direction. This makes it a nervous thing to fly.

I suspect it relates to what my gyro/FC is doing, as seen in the video. The horizon moves as if it is being tilted, however Im keeping it perfectly flat.

*to note I have got roll set -6 and pitch set to 8 under ' Rotate virtual attitude relative to the board' to counter act it drifting forward and right when hovering (although it doesnt work too well, it still drifts).

Flight mode 1 is attitude hold, attitude hold, rate

Flight mode 2 is rattitude, rattitude, axis-lock with i-pids for yaw set to zero.. just testing combos

Any help would be great!

Thanks in advance

Greg
 

[TheOtherCliff]

Assuming that all motors run well through quick power changes and that the battery can supply enough power so that it isn't dropping out.

First of all, don't change the transmitter trims from where they were when you did setup.

Next, do ESC calibration and neutral setting.
https://librepilot.atlassian.net/wiki/display/LPDOC/ESC+Calibration

Next, disable pirouette compensation (bottom of Stabilization->Advanced).

This issue is caused by some ESC/motor/prop(s) being weaker than others in some regard.  A yaw command says "every other motor speed up and the other 3 motors slow down".  The result should be a little more twisting, but nothing else.  Now if only every other motor is running and one is weak it will fall toward the weak motor.

[greggles77]

Thanks the Other Cliff, I'll re-calibrate the ESC's again.

Any thought on what the flight info horizon feeding back when the drone is pivoted on a flat surface?  Why would it be appearing it as if the drone is banking? Seen that before?

Also, with the ESC tuning - https://librepilot.atlassian.net/wiki/display/LPDOC/ESC+Calibration
Why is it better to do it that way rather than using the calibration steps under the Hardware wizard in Libre Pilot? Do they not achieve the same objective?

[TheOtherCliff]

Any thought on what the flight info horizon feeding back when the drone is pivoted on a flat surface?  Why would it be appearing it as if the drone is banking? Seen that before?

If (motors off) you can sit it on a flat surface and hand spin it and the PFD/AH on the FlightData page shows banking, not simple spinning like a top, then you have a different issue.
If it does that then:  Did you mount the FC normally (servo connectors up and arrow forward and board flat and level when aircraft is hover mode level)?  Is your hex designed normally with motors pointing straight up?  If no to either, you must adjust Attitude->Settings->RotateVirtual.  You might also redo accel calibration and board level on the Attitude->Calibration page.

Also, with the ESC tuning - https://librepilot.atlassian.net/wiki/display/LPDOC/ESC+Calibration
Why is it better to do it that way rather than using the calibration steps under the Hardware wizard in Libre Pilot? Do they not achieve the same objective?

Both places explain and do motor neutral setting.  Only the wiki page does ESC calibration.  @f5soh tells me that the hardware wizard also does ESC calibration so both places do that too.  I know that the wiki explains a way to do it that doesn't even need the RC transmitter.  ESC calibration and motor neutral setting are two different operations.

More:  You might also reduce Vehicle -> MixLevel -> Yaw (you might retune yaw PID after this one)
and Stabilization -> Responsiveness -> RateYaw

[f5soh]

Both places explain and do motor neutral setting.  Only the wiki page does ESC calibration.  These are two different operations.

The Vehicle setup wizard allow the Esc calibration as well, the same way as the manual method does.

[greggles77]

Ok great - I'm very grateful for the help I get in this forum. It makes the change from planes to drones even more fun having the support for the clever bits.

I'll try a full re-calibration and see how I go. I'm not sure exactly what 'hover mode level' is but the  FC is in the default place that HK put it when I bought the quad. All motors also in their default position as per purchase.

[TheOtherCliff]

When it is hovering, all your motors point straight up.

If that is how it is built then it will be as expected, but if the motors are tilted, (some racing quads tilt all motors forward) then applying that rule (when it is hovering, all your motors point straight up) the motors will point straight up and the body will be tilted during hover.  In this case, the FC is not level when the quad is hovering.

Crash damage etc. can cause one or more motors to be a little off from straight up.  In that case the rule (when it is hovering, all your motors point straight up) does the best that it can.  It averages all the motor directions, and that points straight up.  The FC isn't level during hover by a small/fractional number of degrees.

Even when built perfectly, some copters don't hover level.  If it has an odd number of lifting motors (basically helicopter and tricopter) it does not hover level.

[greggles77]

Fantastic, did a complete ESC recalib and also retuned the transmitter, re-centred all sticks etc. Defaults pids. No more weird banking when when applying yaw, turns nicely on the spot. Big thanks.

Took it for a real good hammer this afternoon and it reacted to yaw really well. In fact it the best flying I've had with it, strapped it all over the football oval. Even chased a stray dog off with it that was interested in my kids lunch.

She still drifts front left a bit, however that did have a damaged front arm that I repaired, perhaps the motor is not perfectly level. I have to put back the offsets in the "adjust rotate virtual" roll in GCS -> Configuration -> Attitude => Settings... it seems to help a little bit.

Big thank you again 

[AerialPerPlexity]

The rotate virtual relitive to the board you keep talking about is the setting to change the way the board sits in the craft. You should not change it unless the board is Mounted (180)upside down or sideways or turned to make the USB cable  easier to access (90,-90).  So in less your board is sitting-6 and 8 degrees from level your fc thinks it trying to level itself  with the quad to make it level making it fly crazy cuz it is always trying to level itself. Making it fly erratic.  You should try to use the trim on your controller  to keep it stable in the air. But don't forget the air/wind will push the quad .

[greggles77]

Thanks for that, that makes a lot of sense.  My fc board sits off to the left hand side a bit (however is flat and pointed forward) - could be ing off centre affect it (i.e the centre axis)?

If not, I am thinking it may well be a weight issue or underpowered motor making it drift front left a bit.  Cheers for the reply.

[TheOtherCliff]

RotateVirtual is the place that you adjust to make it hover (Attitude mode) without drifting.    First of all, set your transmitter trims to where they were when you did the transmitter wizard.  Then adjust RotateVirtual:
 - if it is drifting forward you subtract from pitch
 - if it is drifting left you subtract from roll

It doesn't help just a little.  You can over correct and have it drift the other way. 

It doesn't matter where the board sits or if you have weak motors.  The "I" term in PID takes care of that.  If you think you have a weak motor or not balanced, then you really should disable PirouetteCompensation (Stabilization page bank#).