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Jul 01, 2012, 11:04 PM
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Xnaron's Avatar
Discussion

Naza w/gps sudden altitude drop on slow yawing


EDIT Aug 31/2012: SUMMARY: If you are getting sudden drops in altitude when yawing with the sun low in the horizon then cover the left side of the naza with black tape. The barometer is on the left side and it is sensitive to sunlight. I have all of my nazas completely covered and have not had any issues with altitude drops since.


I am creating a separate thread for this as the naza gps thread is getting to big.

I noticed an issue today with my setup and possibly the naza. If I have the throttle set at 50% in GPS or Atti mode it will hold altitude very well. However if I initiate a slow yaw about 1/2 to 3/4 of a turn in the altitude drops like a rock about 5 to 10 feet then recovers. You can see it happen at about 1:30~ in this video. It happens every time. I have a throttle lock switch on my transmitter and I lock it in at 50% throttle and initiate the yaw and the same thing happens. I used the switch to eliminate the chance that I was unintentionally mixing in some throttle while yawing.

I am running the simonk flashed esc's. I'm not sure but it might be worse with a heavier setup. When I tested without the gopro I don't think it happened as bad. I can manually compensate with the throttle to anticipate the drop but I think this may be a software issues. It holds altitude perfectly in atti or GPS modes without yawing.

My gains are all set very high around 200% with 230% on the vertical gain. Has anyone else noticed this?

To reproduce try holding a slow yaw while throttle is at 50% and see if you get the drop.

I am uploading the video now and I'll post the link here when it is done.

I'm going to try bumping the yaw gain down to 120% and the vert gain down to 210%

Scroll to about 1:30~ and it will happen shortly after.
Naza GPS Gopro testing (11 min 31 sec)
Last edited by Xnaron; Aug 31, 2012 at 08:32 PM.
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Jul 01, 2012, 11:17 PM
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Glad to see I'm not the only one seeing horrible naza performance when its doing anything else other than hovering. Look at those wobbles at even slow descent, holy ***.

<cue in DJI fanboys>
Jul 01, 2012, 11:39 PM
DJI Support
Tahoe Ed's Avatar
tc so nice to see you join the party. Xnaron, I think that your gains are too high. I like to start at 145/145/130/150 and 90/90 for the Atti with 30% expo on the Ail and Elev channels. Have you balanced your props? You have a lot of vibration going on. I am assuming that you have you GoPro hard mounted. If not, how do you have it mounted.
Latest blog entry: N3 esc calibration
Jul 01, 2012, 11:40 PM
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chuenwe's Avatar
I remember I had the same problem about altitude drop when yawing, when I first set mine up. My ESC was in all the default setting with low timing and slow rate, and for helicopter. After I changed my ESC to all the fast settings, it doesn't have that problem any more.

I just re-configure my entire hexa in the last few days and did a flight time test today. Did a couple of slow yaw and it held 100% sollid. My hexa is heavy as well. 3.02kg!

My gains are:
Pitch/Roll: 185%
Yaw: 130%
Vertical: 140%
Attitude Gain: 140%

I'll upload the video to youtube in a moment.
Jul 01, 2012, 11:47 PM
Registered User
Xnaron's Avatar
Thanks...I did have gains set similar to that when I was running stock esc firmware. With the simonk firmware I can crank up the gains. Think you are correct though that I mos likely need to turn down some of my gains. I am going to start with turning down my yaw gain to 120% and going to lower my vertical gain to 210%. I found with vertical gains under 200% I would get bobbing on altitude hold. The simonk firmware makes a huge difference to the performance of this thing btw.

Thanks for posting your gain settings. Much appreciated!

Quote:
Originally Posted by chuenwe View Post
I remember I had the same problem about altitude drop when yawing, when I first set mine up. My ESC was in all the default setting with low timing and slow rate, and for helicopter. After I changed my ESC to all the fast settings, it doesn't have that problem any more.

I just re-configure my entire hexa in the last few days and did a flight time test today. Did a couple of slow yaw and it held 100% sollid. My hexa is heavy as well. 3.02kg!

My gains are:
Pitch/Roll: 185%
Yaw: 130%
Vertical: 140%
Attitude Gain: 140%

I'll upload the video to youtube in a moment.
Last edited by Xnaron; Jul 02, 2012 at 02:05 AM.
Jul 01, 2012, 11:52 PM
Registered User
Xnaron's Avatar
Quote:
Originally Posted by Tahoe Ed View Post
tc so nice to see you join the party. Xnaron, I think that your gains are too high. I like to start at 145/145/130/150 and 90/90 for the Atti with 30% expo on the Ail and Elev channels. Have you balanced your props? You have a lot of vibration going on. I am assuming that you have you GoPro hard mounted. If not, how do you have it mounted.
Hi,

Yes I had to have gains like those when I was running stock esc firmware but as I mentioned above not with the simonk firmware. My props are statically and dynamically balanced and I do have expo dialed in. The gopro is soft mounted. The battery and the gopro hang on a tray that is mounted to the frame with soft rubber tubing.

I should mention that I have no other issues with the naza besides this and I am extremely happy with its performance.

What made you think I had a lot of vibration going on? Maybe in the video it might sound like it but in person it actually is very smooth. The props are all dynamically balanced. I will double check them to make sure nothing has changed.

thanks for your reply!
Jul 02, 2012, 12:59 AM
Registered User
What's causing those horizontal lines in the video. I realized they are present at certain headings (or maybe motor repm)...
I wonder what's causing it...
Jul 02, 2012, 01:06 AM
Suspended Account
props
Jul 02, 2012, 01:11 AM
Registered User
Xnaron's Avatar
Quote:
Originally Posted by iskoos View Post
What's causing those horizontal lines in the video. I realized they are present at certain headings (or maybe motor repm)...
I wonder what's causing it...
The sun going through the props. The sun was low in the sky and hit the props at the right angle to cause that. You can see as I change heading away from the sun it goes away.
Jul 03, 2012, 03:51 PM
Registered User
Xnaron's Avatar
I ran some tests without the gopro onboard the next day and it was better. Maybe very slight dropping in altitude during yawing but nothing like the sudden drops the previous nights. This makes me think it is related to load but more theories below...

Some other users posted that they could reproduce the issue but fixed it by changing the timing on their esc's to high. Not an option for me with my flashed esc's.

Another user was posting about altitude hold issues when the naza wasn't covered. I wondered about this as well. Sunlight can also affect the barometers. I previously had my naza unit covered with a black dome. Altitude hold worked well. But I can't remember if I tested slow yawing. I moved the naza to a dji style quad with no cover and I noticed I'd get sudden altitude drops while yawing slowly. At the time of the testing the sun was strong and low in the horizon. I am wondering now if perhaps I got the drops when I yawed the naza unit and the sun hit it in a certain spot. It was windy at the time too and it could also have been turning the unit into the wind. This happened to me with a gopro in place. When I tested the next day without the gopro it was better. But the sun was high in the sky and it was not as windy. I'll need to do some more experimenting. I can block the wind and sun with some foam and try again with the gopro on.

I need to retest with sun high and no wind. I also need to retest on 4s. Below are images of the old quad with naza under the black dome and the new quad with naza between the center plates.
Jul 03, 2012, 04:09 PM
pbw
pbw
arachnida
pbw's Avatar
Looking at your video you have exactly the same problem as I have. When the sun shines on the left side of the NAZA you get a drop. I had this too and noticed it happend always with the nose pointing to the same direction. I was able to fly into the shade of my house and the NAZA went up again.

Try to cover the left side of the NAZA FC with some black tape and please report if your issue is gone. I'm almost sure it will be!

Cheers,
Arachnida
Jul 03, 2012, 04:14 PM
Registered User
Xnaron's Avatar
Quote:
Originally Posted by pbw View Post
Looking at your video you have exactly the same problem as I have. When the sun shines on the left side of the NAZA you get a drop. I had this too and noticed it happend always with the nose pointing to the same direction. I was able to fly into the shade of my house and the NAZA went up again.

Try to cover the left side of the NAZA FC with some black tape and please report if your issue is gone. I'm almost sure it will be!

Cheers,
Arachnida
Thanks I will try that. Did you find that the tape was enough? Just on the side?
Jul 03, 2012, 04:36 PM
pbw
pbw
arachnida
pbw's Avatar
Quote:
Originally Posted by Xnaron View Post
Thanks I will try that. Did you find that the tape was enough? Just on the side?
In fact I used some thin black foam with two sided glue on it that I also used to put the NAZA on the bottom plate of my frame.

I only covered the left side as the barometer is on that side, but if I find some spare time I will cover the complete NAZA case. I also informed DJI about this, they replied once to ask more info but didn't confirm this yet as an issue.

Should be easy to test using a strong flashlight or maybe even a laser pointer.
Jul 03, 2012, 04:37 PM
Registered User
Xnaron's Avatar
Quote:
Originally Posted by pbw View Post
In fact I used some thin black foam with two sided glue on it that I also used to put the NAZA on the bottom plate of my frame.

I only covered the left side as the barometer is on that side, but if I find some spare time I will cover the complete NAZA case. I also informed DJI about this, they replied once to ask more info but didn't confirm this yet as an issue.

Should be easy to test using a strong flashlight or maybe even a laser pointer.
Excellent info! Thank you for posting!
Jul 03, 2012, 05:50 PM
Registered User
Quote:
Originally Posted by Xnaron View Post
Excellent info! Thank you for posting!
I also had the same problem as you. My rig is 1.8 kg dji450. I fixed it by changing the motor timing in the program. From recommended to high...


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