Slow Rotation to the left...

I posted this in the Droidwrorx forum as part of another thread but thought I might ask it here also....as this is the DJI forum.

I am experiencing a slow rotation to the left (rudder) when hovering in GPS mode. It will only hold steady if I hold in some right rudder. No issues with altitude holding or lateral hold.

These are the particulars: Droidwarx CX-4, Doridworx AXI 2217/20 motor with DJI Speed Controller. 5000mAh (35C) Li-Po. Futaba MZ14 / R6208SB. CX4 GPS was recalibrated. Assitant Software setting for the GPS is measured correctly and keyed in. Throttle was mid-point (green) when "write" was selected. All trims and sub trims were at "0" when connected to the Assistant Software.

I added trim in flight to try and get it to stop - but it really had no effect so I went back to "0" trim. Attached are pictures of the mounting of the GPS.
View attachment 10752View attachment 10753

Any ideas about what could be causing this would be appreciated. I can't trust it to fly until I can get this solved.

Thanks,
Dale.
 

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Tahoe Ed

Active Member
Did you calibrate your compass where you were flying? When was the last time you did it and have you added any equipment since then. It sounds like a compass issue. Any crashes that may have damaged the GPS puck/Compass? I would recalibrate your compass and try again. I am also not a big fan of your GPS/Compass mount. It looks like it could be subject to vibration and movement in flight. I would mount it on an arm or the shell, just try a different location to see if that helps. Also can you post your GPS x,y and z settings?
 
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Thanks Tahoe Ed.
Yes, I calibrated the GPS with the calibration "dance" just prior to taking off.
No, I had not had any "crashes".
No, I have not added anything to it - it's still new and I'm trying to work the bugs out before I add anything else.
Current settings for the GSP"
X = -11
Y = 0
Z = -2

View attachment 10754

I understand your point about the GPS puck location - Razzil had commented on his (sticking out the back on a metal tongue) also. I originally had it mounted to the top of the canopy but didn't like that it was tilted slightly forward so I made the plate out of CF sheet and mounted it level with the Naza.
 

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Did you calibrate your compass where you were flying? When was the last time you did it and have you added any equipment since then. It sounds like a compass issue. Any crashes that may have damaged the GPS puck/Compass? I would recalibrate your compass and try again. I am also not a big fan of your GPS/Compass mount. It looks like it could be subject to vibration and movement in flight. I would mount it on an arm or the shell, just try a different location to see if that helps. Also can you post your GPS x,y and z settings?

I have moved the GPS puck (see the pictures) to the Right Rear arm using two of the additional mounts for the arms and the motor mount. I have recofigured the location in the Assistant Software.
View attachment 10758


View attachment 10761View attachment 10760View attachment 10759

No change. It still rotates slowly to the left (no thanks to Will Farrell).

The only other thing that I can think of is to change out the GSP puck to see if that makes any difference. I'll have to remove the one from the F450 to try this.....

I don't know how these old pics (below) got attached - ?
 

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DucktileMedia

Drone Enthusiast
It's normally not necessary to move the gps but rather rotate it a little. But if you want to be real fussy about it, you can make sure it lays on an increment of a whole number since there are no decimals in the software.
 

It's normally not necessary to move the gps but rather rotate it a little. But if you want to be real fussy about it, you can make sure it lays on an increment of a whole number since there are no decimals in the software.

I tried rotating it +15 degrees and - 15 degress to see if it made any difference .... and .... nothing. It still rotates slowly to the left. I don't think that the VU will flash a gree light if the GPS disc is not picking up the GPS satellites - so, that point as a fact, althouhg I don't think that the GPS puck is defective, I don't see anything else that I can try to get this to lock into position.
 

DucktileMedia

Drone Enthusiast
All ESC's calibrated the same? I dont know the answer, just throwing out ideas. These things can be very frustrating sometimes.
 


tstrike

pendejo grande
Does it rotate even if you unplug the gps? All your motors are perfectly parallel to one another? I had a slow rotation to the right and it ended up being 2 of the 6 booms were slightly tweaked.
 

Does it rotate even if you unplug the gps? All your motors are perfectly parallel to one another? I had a slow rotation to the right and it ended up being 2 of the 6 booms were slightly tweaked.

tstrike - please define "tweaked"? I confirmed during the building process that the booms fit into the detents (nipples) and that they were "square" to the frame. I've just confirmed that all blades tips are at the same level / height to each other with a dial indicator (not exact as the body rests on a frame that is not 100% level - but that shouldn't matter when it's flying).
 

tstrike

pendejo grande
tstrike - please define "tweaked"? I confirmed during the building process that the booms fit into the detents (nipples) and that they were "square" to the frame. I've just confirmed that all blades tips are at the same level / height to each other with a dial indicator (not exact as the body rests on a frame that is not 100% level - but that shouldn't matter when it's flying).

I meant the motor twisted to one side or the other of the arm, on my round boomed ship there's no indents or anything to help with motor alignment. Another thing, did you go into tools in naza assist and do the imu calibration?
 

tstrike - thanks.
On the V2, there are indents in the boom / motor mounts to support the alignment. I guess they added those with the V2?

IMU calibration? No - I have not done that. What I have done is the GPS calibration (page 32 in the Naza v2.6 manual). Is that necessary? I saw the section on eliminating the Toilet Bowl Effect, but that's not what I have. I also thought that the IMU only came with the WooKong system? There aren't any real clear instructions on how to calibrate the IMU. Got any tips?
 



z_man_95

Member
My f550 w/ naza has the same problem. I repositioned the lipo and it seems to have solved my problem. Would off center cg cause this? I'm thinking that one motor is compensating for the imbalance causing it to yaw. Not sure though as I'm still new to these.
 

The imu calibration is under the tools menu (upper left corner of the screen in assist). http://www.multirotorforums.com/showthread.php?6045-IMU-Calibration
worth a shot.

Thanks tstrike. I looked at the thread but was unable to see the video's as they showed "This video is private". I've contacted Exploracam to see if I can gain access to them. Most of the thread was discussing "Right Drift" (Y axis), but I think my issue is the X axis. I don't think that I can add pieces of paper to correct this problem so hopefully the IMU (re) calibration will help.

Look at page 38 of the Naza Manual it will show you how it is done.

Thank you Tahoe Ed. When I accessed the IMU calibration in the Tool menu, I clicked the "Check IMU status" button and it responded that I didn't need to calibrate. I did anyway. (I didn't capture the settings prior to clicking 'calibration')
It is now showing:
"Gyroscope" X=0.0 Y=0.0 Z=0.0
"Acceleration" X=0.0 Y=0.0 Z=-1.0

Do all of the readings need to be 0.0?

Dale.
 

Buggah. It's still rotating - left - even after calibrating the IMU and making sure that the throttle was centered when I hit "write".

I have not tried a different GPS puck - maybe tomorrow.

I'm leaving on Tuesday and am still plannig to take it with me.....starting to get a bit frustrated.

Dale.
 

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