(Solved) Please help! Not able to complete. Why?
I have a plan that it can not complete.
Everything is fine until the last 2 marks.
The mission always stops between the next to last mark and the last mark.
It just stops and hovers there between the last 2 marks (close to the next mark to last one)
And, I have to pause the plan and land the drone manually.
Only the mission, I have this kind of problem and all my other missions are all ok.
Could you please help me to check it and help me find the reason why it can't complete?
By the way, there is no error message and the mission was just running, the aircraft did not move forward but just hovered there.
The plan's link and my aircraft is DJI Air 2S:
Comments
23 comments
Have you checked logs in something like Airdata? There may be messages there that would give a clue to why it is stopping
Barry Houldsworth
I am checking it and everything looks fine without any error nor warning.
The mission looks ok, right? I will try it again another day.
Ray Kao
I didn't see anything obvious between those points. Did you run it multiple times or just once?
A couple of things to consider.
Barry Houldsworth
Thank you for your kind information.
This is the third time and all of them stopped just after the next mark to last.
1. Yes, there is an open space and no any flight restriction zone.
2. Good hint.
I doubt it is caused by the last mark.
The last mark is just set at the last waypoint and the height difference between the last two marks causes the situation.
I will try to adjust the last mark and have another test.
With preview I noticed the camera capture marks were very close together after marker 31. Watching the preview run the horizontal speed drops to about 0 just as the descent from 295 to 52 feet begins. It seems that the horizonal distance between 31 and 32 is not sufficient to achieve the descent so the drone slows to 0 as the descent begins, then picks up a little. Giving the drone more horizontal distance to achieve the descent would help the speed issue.
How much vertical descent happened before the mission stopped?
What movement clues are in AirData?
This is a long mission at 25 minutes and you still have about 2,000 feet for RTH. Any clue about how much battery was left when it started hovering? Do you think that had some bearing on the stop?
Definitely need to Adjust the distance and/ or altitude between those two markers, 31 & 32.
Mike (Arizona Wyldwest) David Ritter
The distance between 31 & 32 seems to be not far enough to descent.
Originally, I thought so, but....
(1) If so, is it a kind of bug? Since, in the mission preview, the mission is completed without any problem.
(2) The landing (ending) spot is a special location and I want to do a "Push-in" ending. So, how far distance is enough to descent from 295ft to 52.5ft?
It will likely take a lot of trial and error. When you run a mission preview pay attention to what is happening as it gets to the descent point from 295 feet. Watch how the drone slows down to start the descent and then moves very little until it gets to the final level and then continues flat to the end. So the descent isn't gradual for the entire last leg. One of the problems I had was it was taking too much time to generate every change of parameters and it didn't want to create a test mission of just the last 3 markers; it might be an option. It might be an option to create a short test mission of just the last three markers where you can fly right from your home to see if it works.
Another option I didn't try would be to add markers between the last to to force a more gradual descent to your end point. I may try that myself and another option.
I have an Air 2s so I know it can handle very rapid descents, maybe more than dronelink can manage.
I did another check and changed the interpolation to curved for the last 2 markers and adjusted the slider to the center force a gradual descent. Even so it has to descend about 250 feet in a short time span. The done is forced to slow down to about 0.5 mph to make the descent in the 25 second time span descending at 10 fps. At 0.5 mph it may difficult for dronelink to manage that speed in real flight.. You could also in the mission settings increase the vertical maximum descent to 13 fps which would allow the drone to increase horizontal speed by 0.1 or 0.2 mph but the high vertical descent rate introduces another potential off-course error; I've had that happen.
In the end I think the final 250 ft descent in 25 seconds is too much so doubling the distance between the last 2 markers might be a good start. Unfortunately you won't know until you fly the entire mission on location. That's were a short test mission might be a good plan.
David Ritter
Thank you very much.
I create another mission and it proves that your answer is the root cause of the issue.
Why does it slow down to 0 H-Speed before the descending only when the distance between two marks is short?
The mission's link: https://app.dronelink.com/skycyclist/dronelink-sample-and-support/plan/7lESypBMwUCWI5DFv9Yo/S45DhRL3RbxFvbffNRk9
David Ritter
The vertical behavior is also different for different distance.
When the distance between two marks is long, the vertical speed will slow down when it is coming to the bottom.
But, when the distance is short, the vertical speed behaves very different...
It seems to be the same issue about DL's vertical path. It can't do vertical "Push-in" with DL...
It will slow down when it near the bottom of the descending.
But, it does not slow down the vertical speed when the two marks are too close.
There are other changes in Settings which you could investigate. The V Acceleration/Deceleration should control how quickly the change in descent/ascent starts to make the changes more gradual and less change of an off course error. I don't think they would make the stop-in-flight error go away though.
The flight data record is likely you best place to look for the error. I use AirData but I upload each flight manually. The data isn't public but could be subpoenaed if needed; as long as you have nothing to hide that's OK. You can learn a lot about each flight when you review the data after each flight.
I'll need to take a break until tomorrow. Thanks for your updates, but I need to wait until tomorrow. Check my notes on the v acceleration/deceleration rates.
Ray Kao
Good start on the short plan but some suggestions: Use the same altitudes for the markers as you have for the the main plan. Make sure the timeline shows about 25 seconds for the 250 foot drop.
You can make the descent start smoother by making the descent acceleration to -1 fps. Some of the descent starts before the marker. Check the preview chart for descent rate and horizontal speed.
The next step would be to actually fly the test mission. Make sure altitudes are correct to not crash into the ground.
As for AirData you can get a lot of information and interpret it for yourself unless you need crash data (you don't). If you have the first level of paid version you get an analysis of the flight wind conditions. The free version will give you battery and ampere information so you can look for problems them. You will also get line by line of altitude, speed, battery %, and more. Error notifications will also show. Just upload the flight.txt file.
How many times did you actually fly the mission?
Hi Ray. The mission preview is just for checking the plan to ensure it’s doing what you wanted. It will not indicate every possible error. You are just going to need to test how much distance is needed at the descent to your altitude. Trial and error.
An idea would be to create a very short plan with a path section with just those markers set to same values. Make several copies of it and then try moving back marker 31 a little bit more on each one of them. Then you can just fly those very short missions and see which one works. Save a ton of time since the issue is at the very end of the plan. Good luck. 😎
Mike (Arizona Wyldwest)
I have just completed 5 small different path missions' tests and all of them failed and were not able to be completed.
Well, it appears to me that the issue is the "last mile" of Dronelink's perfection.
Dronelink is super powerful but it just can not be used to do rapid vertical path missions. I can do all expected waypoint missions with DL but only can't do this part.
It could be the "last mile" toward Dronelink's perfection.
And, for me, it is really an issue for every flight since I will like the aircraft to descend to a lower altitude at the end of the mission and then I can land the aircraft safer.
Besides of that, the vertical Push-in or Pull-out are quite basic and significant drone movements and very needed.
Here is one of the 5 tested missions for your information:
https://app.dronelink.com/skycyclist/dronelink-sample-and-support/plan/B7AMpi7RN3UYXEGyQ6Mu/dANPOyrvtpZpG25Hk9ip
I tested the mission twice and both flights were failed to complete.
The results are all the same:
More information from the tests
With "High Wind Tolerance" disabled, it was stopped at similar point with the error message:
Drone Too Far Off Course: A -7.9 m
With "High Wind Tolerance" enabled, it was stopped without the error message. And, it needed to pause the plan to take over the control of the aircraft.
I am trying to increase the "Motion Error Tolerance" and if it helps, I will post the result.
Good news.
After adjusting the "Motion Error Tolerance" value, the mission is able to be completed perfectly now.
I am so happy with Dronelink and the community.
Case learn:
It is such a long journey but comes out with a happy ending.
Ray Kao
That's great news. Great to see the community diving in to help with the diagnosis and your dedication to finding the solution. Well done!
Ray Kao
I've had missions stopped due to off course with rapid descents; that's what was interesting about yours--no error. In those cases I didn't have the high wind tolerance checked. More recently I enabled high wind tolerance thinking it would help to stay on course but your findings indicate that it disables the off course error message. In my case I had to keep tight vertical tolerance as the mission was descending over water. I guess I'll disable the high wind tolerance just to get the error message; when I know the error I can adjust altitude and resume.
Thanks for keep us up to date.
The primary use case for high wind tolerance is to allow maps to complete with the drone flying slower on upwind legs.
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