Loss of control after upgrade

[jakerizzo]

Loss of Control After Avata Upgrade
Hello, everyone. I'm hoping for some input after my crash yesterday. I did the AxisFlying 3.5 frame and motor upgrade on the avata, and took it out yesterday for the first test flights.
First one went fine. 10 minutes of slow cruising. Stayed in normal mode, low, and close to home.
Second flight I sent it up to look around at 29 stories. Got up no problem, but felt like I was getting buffeted by the wind more than usual, which was unexpected with the heavier weight and bigger props. Came down to find calmer air, and as I got lined up for a straight run above a street, all hell broke loose.
You can see as I line up with the brick street and begin descending, the drone starts oscillating from side to side. My first move was to hit the brakes and throw it into hover. You can see where it attempts but then immediately disengages.
My second move was to cut all throttle and get down as fast as possible before it lost all control. I was afraid it was going to flip over on it's back. As I cut power, I also tried to nudge it left a little too try for a parking lot landing instead of the middle of a street.
None of that worked. It kept rocking wildly and lost altitude slowly. It did get to the left a little, but crash landed on a parking garage roof. Battery went from about 59 percent to zero upon landing, and I think I had an ESC error in the googles but I was more focused on getting it down than reading the HUD.
Opened everything back up today and double checked all my soldering. No bridges and nothing loose, as far as I can tell, but I'm hesitant to put it together and get it back up in the air without some opinions on what the problem might be. Hoping for some input and direction. Thanks in advance.

 

[BudWalker]

The .DAT log file may help some. It will have motor data such as RPMs, voltage, current, etc. It will also have the motor commanded data.

If you had the mobile device connected to the goggles and the Fly App is set to not synch with DJI that .DAT will exist on the Fly App. Take a look here
Mavic Flight Log Retrieval and Analysis Guide
to see how to retrieve the .DAT from the Fly App.

If the mobile device was not connected to the goggles during the flight the .DAT can first be moved from the goggles to the Fly App using the method described here
.DAT available

 

[Kilrah]

Looks like there may be some prop vibration, could be throwing the FC out of whack.

Or the fact they change characteristics without doing any tuning adjustments just doesn't work right.

 

[BudWalker]

Kind of interesting that the instability is just in roll. Just about any explanation I can think of would cause instability in all 3 axes.

@jakerizzo did you actually see this roll instability? I.e., is it possible the gimbal is loose and the Avata itself is not rolling?

 

[jakerizzo]

Kind of interesting that the instability is just in roll. Just about any explanation I can think of would cause instability in all 3 axes.

@jakerizzo did you actually see this roll instability? I.e., is it possible the gimbal is loose and the Avata itself is not rolling?

Oh yeah, I saw it. Could hear it clearly as well. My spotter said it looked crazy. In the video I attached, it starts at 2:01

 

[jakerizzo]

Loss of Control After Avata Upgrade
Hello, everyone. I'm hoping for some input after my crash yesterday. I did the AxisFlying 3.5 frame and motor upgrade on the avata, and took it out yesterday for the first test flights.
First one went fine. 10 minutes of slow cruising. Stayed in normal mode, low, and close to home.
Second flight I sent it up to look around at 29 stories. Got up no problem, but felt like I was getting buffeted by the wind more than usual, which was unexpected with the heavier weight and bigger props. Came down to find calmer air, and as I got lined up for a straight run above a street, all hell broke loose.
You can see as I line up with the brick street and begin descending, the drone starts oscillating from side to side. My first move was to hit the brakes and throw it into hover. You can see where it attempts but then immediately disengages.
My second move was to cut all throttle and get down as fast as possible before it lost all control. I was afraid it was going to flip over on it's back. As I cut power, I also tried to nudge it left a little too try for a parking lot landing instead of the middle of a street.
None of that worked. It kept rocking wildly and lost altitude slowly. It did get to the left a little, but crash landed on a parking garage roof. Battery went from about 59 percent to zero upon landing, and I think I had an ESC error in the googles but I was more focused on getting it down than reading the HUD.
Opened everything back up today and double checked all my soldering. No bridges and nothing loose, as far as I can tell, but I'm hesitant to put it together and get it back up in the air without some opinions on what the problem might be. Hoping for some input and direction. Thanks in advance.

 

[jakerizzo]

Well I had low voltage at 2:08, the ESC overheated 4 seconds later. I guess I did something wrong in the soldering

 

[BudWalker]

Well I had low voltage at 2:08, the ESC overheated 4 seconds later. I guess I did something wrong in the soldering

Is there a .txt we can look at? A link to the AirData report will have a link to the .txt.

The .DAT will have individual motor data so you should be able narrow the search for a soldering issue.

 

[Barbara]

What about the recurring RC Stick errors?

 

[jakerizzo]

Is there a .txt we can look at? A link to the AirData report will have a link to the .txt.

The .DAT will have individual motor data so you should be able narrow the search for a soldering issue.

I'm not finding a way to link the AirData report from inside the app. Trying to get flight logs moved over from DJI fly now

 

[BudWalker]

I'm not finding a way to link the AirData report from inside the app. Trying to get flight logs moved over from DJI fly now

 

[jakerizzo]

Mar 25th, 2023 08:03AM | General / Overview | DJI Fly log 1.0.1 | United States | Airdata UAV

DJI Fly app flight log from Mar 25th, 2023 08:03AM, version 1.0.1 on , in United States. General / Overview | Airdata UAV

app.airdata.com

 

[jakerizzo]

What about the recurring RC Stick errors?

Recurring stick error has been constant since I first started. I can land and calibrate 50 times and as soon as I take back off, the error returns

 

[Barbara]

Recurring stick error has been constant since I first started. I can land and calibrate 50 times and as soon as I take back off, the error returns

You were getting these even before the mod?

 

[BudWalker]

Mar 25th, 2023 08:03AM | General / Overview | DJI Fly log 1.0.1 | United States | Airdata UAV

DJI Fly app flight log from Mar 25th, 2023 08:03AM, version 1.0.1 on , in United States. General / Overview | Airdata UAV

app.airdata.com

I suggest that you resolve the RC stick errors so we can be sure that's not related to the issue.

That said let's assume, for the moment, that it isn't related to the issue. From about 133 secs to the end of the flight pitch and roll are oscillating in a synchronized manner. Further, they are oscillating inversely. This would happen if either the rightFront or leftBack motor were switching on/off. If the relationship were not inverse the suspect motor would be the rightBack or leftFront.


Sure would be nice to see a .DAT.

 

[BudWalker]

Further, at about 123 secs the battery current climbs from about 12 amps to 36 amps. This suggests to me that the rightFront or leftBack motor may be blocked or otherwise hard to rotate.

 

[jakerizzo]

You were getting these even before the mod?

From the day I switched from the motion controller to the RC. It's never affected the flight, and after the first 10 times I recalibrated and five minutes later it popped up again, I just started ignoring it

 

[jakerizzo]

I suggest that you resolve the RC stick errors so we can be sure that's not related to the issue.

That said let's assume, for the moment, that it isn't related to the issue. From about 133 secs to the end of the flight pitch and roll are oscillating in a synchronized manner. Further, they are oscillating inversely. This would happen if either the rightFront or leftBack motor were switching on/off. If the relationship were not inverse the suspect motor would be the rightBack or leftFront.
View attachment 6261

Sure would be nice to see a .DAT.

I had to go to work, but when I get home I'll continue my quest for the.dat. For now though, could the simplest cause be that I didn't get that motor soldered well?

 

[jakerizzo]

I'll turn then tonight when I get in to check that there's nothing blocking rotation. Thank you so much for helping, sorry I'm such a noob on getting the files

 

[Kilrah]

Kind of interesting that the instability is just in roll. Just about any explanation I can think of would cause instability in all 3 axes.

Roll is the axis with the least inertia, it's common to need lower gains on roll vs pitch on custom quads.