Mini3 drift backwards when landing (RTH) in strong wind

[surfbird]

Yesterday I flew my mini3 in high wind. it was steady 8-9m/s, and it handled it quite well. Could do 8m/s in sport against the wind.

In RTH it flies to the exact takeoff point at RTH alt, but when descending it get pushed backwards by the wind. So it misses the landing sport with at least 50meters.
I canceled the RTH and landed manually without problems.

Strange, have anyone seen something similar?

A little bit worrying since I plan to program some autonomous followme flights and I always used RTH as a backup.
Now it seems like I have to program the whole RTH myself.

 

[AeroJ]

Yeah that's normal - I think RTH takes it out of Sport mode for you, so its resistance to wind is much much less. So it is probable that the speed of the wind was simply too much for normal mode as it tried to land. Cinematic mode would be worse still, but in that case RTH would increase wind fighting power from what you had.

Solution is, as you say, bin RTH as soon as it starts looking not up to the job, and do it in sports mode yourself !

 

[Yorkshire_Pud]

As with most problems ...... the flight log might reveal what happened.
I am suspect you have horizontal control during the descent phase of RTH so it might not have been necessary to cancel the RTH, perhaps an experiment is called for.

It is unwise to fly the outbound leg of a flight down wind in strong wind. Drones have been lost that way after being unable to make sufficient headway agianst the resulting headwind.
That is was blown "backwards" during landing suggests to me that the return was upwind.

 

[Yorkshire_Pud]

If it could actually make headway via RTH then I am a bit puzzled as to why it could not hold position during the descent.
I would have thought it still had the required tilts available to do that and since it was descending it would normally be using slightly less power than that needed to hover so that shouldn't be a problem ..... unless ........

What was the battery charge level ?

 

[surfbird]

If it could actually make headway via RTH then I am a bit puzzled as to why it could not hold position during the descent.
I would have thought it still had the required tilts available to do that and since it was descending it would normally be using slightly less power than that needed to hover so that shouldn't be a problem ..... unless ........

What was the battery charge level ?

It was >30%.

I have to run more tests and check the logs what attitude it has.
I have not seen this in other drones. though.

 

[Yorkshire_Pud]

It was >30%.

I have to run more tests and check the logs what attitude it has.
I have not seen this in other drones. though.

you could perhaps either attach the ,txt log to a post here or upload the .txt log to Phantomhelp

DJI Flight Log Viewer | Phantom Help

Upload and view flight logs from your DJI drones

www.phantomhelp.com

and post the URL here.

 

[Droning on and on...]

The Mini 3(P) does not have Precision Landing, so it wouldn't be abnormal to be as much as 30ft off the home point with a poor GPS sat config at the time of the RTH.

50m is way out of any expected GPS error, though.

 

[WNYBill]

My Mini pro 3 usually is <24 inches off its initial take off point. Not a problem since I use my driveway for a landing pad. I am going to try hand catching. Please take me through the procedure.

 

[AeroJ]

Please take me through the procedure.

People have different techniques of course, but the one I think 'safest' is the following...

1. Put the drone in Sports mode to disable OBS avoidance, which will stop it bouncing away from your hand.
2. Park the drone 1-2 ft above head height so that you need to reach up for it, but not too far.
3. Whichever hand is not controlling throttle should reach up and then be placed about a foot under the craft, with palm upwards and absolutely flat. Watch out for the thumb, which wants to naturally rise at that angle - don't let it !
4. Input gentle throttle decrease until lands in your hand. Once in your hand, hold throttle all the way down to stop motors.

I would say 'Don't try and grab it' unless terrible wind (or jumping dogs!) compel it, but if it does become necessary you should grab it quite firmly and try and stop motors as soon as possible, which is most quickly done by turning the drone upside down as soon as you grab it. This does place horrible stresses on props and motors, but if you save that move for emergencies it should be OK.

 

[Droning on and on...]

People have different techniques of course, but the one I think 'safest' is the following...

1. Put the drone in Sports mode to disable OBS avoidance, which will stop it bouncing away from your hand.

Not true. You can not disable VPS and Landing Protection on the Mini 3(P). It will still try to avoid your hand regardless of N/S mode.

The Mini 4P does have the ability to turn VPS/LP off, and you can then slam it in to the ground at full downward speed. It will not "see" the surface below and autoland.

Makes hand-catching really easy.

 

[Yorkshire_Pud]

1. Put the drone in Sports mode to disable OBS avoidance, which will stop it bouncing away from your hand.

I would be surprised if the downward looking sensors are disabled in sport mode but I don't have a mini 3 pro to experiment with.
Sport mode probably does disable the horizontal OA and that is probably a good thing when hand landing.
Personally I would switch OA off, if it was on, when descending to land but I very rarely have it switched on on the mavic 2s.

With my drones, mavic 2 and mini 1&2, I use a slightly different approach in that I land them in a slightly cupped hand, since I launch that way I have a fair idea how deep the cup can be.

Input gentle throttle decrease until lands in your hand.

I find that the throttle must be fully closed or nearly fully closed in order to over ride the landing protection hover height at 50cm. I just keep it there until the motors stop.

 

[AeroJ]

Yeah, I'm gonna stop answering questions about drones I don't own ! I am repeatedly confounded with the minute changes between models and a few videos that have (mis)informed me about certain functionality !

 

[Yorkshire_Pud]

Yeah, I'm gonna stop answering questions about drones I don't own ! I am repeatedly confounded with the minute changes between models and a few videos that have (mis)informed me about certain functionality !

I think the constant changes to RTH behaviour is a particularily troublesome aspect of DJI's improvements.
It seems to me an awful lot of people don't read the RTH section of the manual or fail to understand, me included, the nuances of words or phrases in it.