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Failure to descend

Hugabeen

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This is a relatively new problem and one I have tried to research with no meaningful results. Quite often now, my M2P will mis-read the altitude and refuse to descend. Although it is more common when I launch at a specific elevation and attempt to descend below the elevation at take-off such as into a canyon or river bed, it has now begun to misbehave regardless of where I launch from.

I have calibrated vision sensors in DJI Assistant 2, Performed a compass calibration and and IMU recalibration. I typically wait a little while after gps home point is locked in prior to launch as wel.

On this most recent flight, I was illuminating a house roof with Lume Cube mounts on the aircraft at night. The aircraft seemed to behave normally until I attempted to descend. I have to initiate auto landing to get the drone to drop altitude and then cancel once it is where I need it to be. If it fails to descend on auto-land, then I will attempt to drop altitude while flying forward at speed. Sometimes this has worked.

I will also disable obstacle avoidance in the event that the low light is creating an issue, however this problem has also occurred many times in full daylight. An email to DJI Technical Assistance was met with crickets chirping, so....

If anyone else has experienced this issue, I would love to know and hear your thoughts and solutions.

Attached Flight Record

Thanks!
 

Attachments

  • DJIFlightRecord_2020-07-15_[22-07-57].txt
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Quite often now, my M2P will mis-read the altitude and refuse to descend. Although it is more common when I launch at a specific elevation and attempt
The cause is obvious.
It's not low light or obstacle avoidance
Here's what your flight data looks like:
You'll see that even when up high, the VPS sensors are showing a false reading.
Above 10 metres, they should show nothing.

You have something blocking their downward view or the sensors are dirty or out of calibration.
If you ever have a problem descending, you can always dosable the VPS sensors and the problem will be gone.
 
The cause is obvious.
It's not low light or obstacle avoidance
Here's what your flight data looks like:
You'll see that even when up high, the VPS sensors are showing a false reading.
Above 10 metres, they should show nothing.

You have something blocking their downward view or the sensors are dirty or out of calibration.
If you ever have a problem descending, you can always dosable the VPS sensors and the problem will be gone.
 
Yes however disabling vision sensors did nothing.
When did you have VPS turned off?
The VPS sensors are showing something close below the drone for almost all of the flight
There was only one short period where you have nothing showing for VPS altitude and also had the throttle down.
That was after 9:13.6-9:15.2.
And the drone responded properly for those few seconds.

This was only for a short period, so I'm not sure if you turned off VPS or it was just a temporary glitch that stopped them working.
 
The cause is obvious.
It's not low light or obstacle avoidance
Here's what your flight data looks like:
You'll see that even when up high, the VPS sensors are showing a false reading.
Above 10 metres, they should show nothing.

You have something blocking their downward view or the sensors are dirty or out of calibration.
If you ever have a problem descending, you can always dosable the VPS sensors and the problem will be gone.
So all I have on the drone is a Lume Cube Light kit. But that doesn't protrude downward. The glass in the IR sensor is pretty scuffed up from countless handling and finger prints over the last 2 years. Maybe it's that. I will look closer at VPS and disable next time to see if that solves it. Thank you for the suggestions.
 
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I had a piece of skin over the very edge of a sensor on my spark and it refused to descend.. actually on take off..it just climbed like a rocket. The problem was solved when I relocated the skin.
 
Update:

Landing assistance. That's all it was. Turned it off and everything was great. Problem solved. I feel like a newbie and pretty embarrassed that this small problem was so simple to solve.

Thanks for all the help, everyone!
 
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Landing assistance. That's all it was. Turned it off and everything was great. Problem solved.
Landing assistance being on still doesn't explain why the VPS sensors were detecting that the drone was only 1 ft above the ground for almost the entire flight.
Does flight data still show the issue with VPS height?
 
Landing assistance being on still doesn't explain why the VPS sensors were detecting that the drone was only 1 ft above the ground for almost the entire flight.
Maybe the downward IR sensor glass being really scuffed and smudged would contribute?
 
It's in the thread. Did you see anything that would indicate it?
It was all over the flight data from the flight with the problem.
I'd have to see data from your latest flight to know if it's changed.
 
It was all over the flight data from the flight with the problem.
I'd have to see data from your latest flight to know if it's changed.

Ok. Ill post yesterday's flight with Landing assistance off shortly.
 
Sensor lenses should be kept as clean as camera lenses. Both need to be immaculate to work well
 
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Virtually impossible with the downward infrared sensors being so close to the ground.
 
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