Logic to trigger a landing

[bonmot]

I normally manually land my Mavic 2 Zoom by holding the left stick down.
No problems so far. But I started wondering that what makes the drone think holding down left stick is a landing. I also hold down the left stick all the way to descend the drone.

I don’t think it uses GPS attitude to decide. Then it must be the IR sensor at the bottom. Then it leads to a possible concern: if during the descending by holding the left stick down, the IR sensor sensed something and think it is close to a surface, is it going to stop the motor?

I think the drone must be doing more completed the logic for landing.
would be really appreciated that if someone has more insight about it.

 

[steve_lyt]

the mavic 2 pro and zoom hover before landing by default. it will come down to about 4ft then wait for you to land it. you can continue to fly by not holding the stick down when in hover at the landing height

 

[OurAngryBadger]

I like using the both sticks down to start motors, faster than using the button in the app, but it scares me that I could accidentally do the same while it's flying and make it crash.

 

[Kilrah]

It triggers landing when at a given height above ground measured by downwards sensors and stick is fully down. It will however not stop motors until it sees no more reduction in barometric altitude. So if landing triggers in the air because of a fake obstacle below (happened to some in fog) it will initiate landing but will just descend slowly for a long time until the ground blocks it from going further down, only then does it stop motors.

I like using the both sticks down to start motors, faster than using the button in the app, but it scares me that I could accidentally do the same while it's flying and make it crash.

Unless you configured the setting for the CSC stick input to allow stopping motors at anytime it is disabled in flight by default.

 

[old man mavic]

the only time my MPP will just land itself is if after pausing it likes what the downwards sensors perceive underneath it
and then only if it is doing a RTH ,for manual landing it will always hover and wait for the stick to be pulled down
it will also put up a warning that the surface where it or you is trying to land is unsuitable and wait for an input from you

 

[sar104]

I normally manually land my Mavic 2 Zoom by holding the left stick down.
No problems so far. But I started wondering that what makes the drone think holding down left stick is a landing. I also hold down the left stick all the way to descend the drone.

I don’t think it uses GPS attitude to decide. Then it must be the IR sensor at the bottom. Then it leads to a possible concern: if during the descending by holding the left stick down, the IR sensor sensed something and think it is close to a surface, is it going to stop the motor?

I think the drone must be doing more completed the logic for landing.
would be really appreciated that if someone has more insight about it.

The autoland mode that you are referring to is ForcedLanding, and it is triggered when VPS height (OSD.sWaveHeight) is less than the parameter HOME.forceLandingHeight and RC_throttle is full down.

 

[FoxhallGH]

The prop's won't stop turning, 'till the Mavic stops descending (i.e. it has touched the ground).

 

[sar104]

The prop's won't stop turning, 'till the Mavic stops descending (i.e. it has touched the ground).

Yes - I should have added that. The FC will not shut down the motors until 3 seconds have elapsed with no further detected descent.

 

[slup]

The autoland mode that you are referring to is ForcedLanding, and it is triggered when VPS height (OSD.sWaveHeight) is less than the parameter HOME.forceLandingHeight and RC_throttle is full down.

Here for some learning ... again

In the chart from my Air below you see me apply full negative throttle from approx 505sec, there the MA is at 2,2m VPS height, well below that HOME:forceLandingHeight of 5m.
But the Forcelanding phase doesn't start until 512sec at VPS height 0,5m.

I know that you wrote "below" VPS height (OSD.sWaveHeight) ... but is the 0,5m VPS height reading also a factor ... or is that 7sec throttle down the factor?

 

[sar104]

Here for some learning ... again

In the chart from my Air below you see me apply full negative throttle from approx 505sec, there the MA is at 2,2m VPS height, well below that HOME:forceLandingHeight of 5m.
But the Forcelanding phase doesn't start until 512sec at VPS height 0,5m.

I know that you wrote "below" VPS height (OSD.sWaveHeight) ... but is the 0,5m VPS height reading also a factor ... or is that 7sec throttle down the factor?

View attachment 95278

I've seen similar results, and I'm not sure whether the FC is ignoring the 5 m parameter or something else is in play. It doesn't generally take 7 seconds to force land.

 

[slup]

I've seen similar results, and I'm not sure whether the FC is ignoring the 5 m parameter or something else is in play. It doesn't generally take 7 seconds to force land.

Mmm ... I was asking because I'm pretty sure that if I had stopped applying throttle there before 512sec the MA had just been hovering. Well another test that needs to be executed once the wind gets down to reasonable levels

 

[bonmot]

I like using the both sticks down to start motors, faster than using the button in the app, but it scares me that I could accidentally do the same while it's flying and make it crash.

That’s exact the reason why I stopped doing it after a couple of times.
EDIT:
After reading other posts I just realized that I was over concerned because by default you cannot just stop the motor in the air.

 

[bonmot]

The autoland mode that you are referring to is ForcedLanding, and it is triggered when VPS height (OSD.sWaveHeight) is less than the parameter HOME.forceLandingHeight and RC_throttle is full down.

What is VPS height? Is it what the bottom height IR senses?

 

[sar104]

What is VPS height? Is it what the bottom height IR senses?

Yes.

 

[BigAl07]

What is VPS height? Is it what the bottom height IR senses?

Are the bottom sensors IR? I don’t have an MP2 but thought they were US sensors.

 

[sar104]

Are the bottom sensors IR? I don’t have an MP2 but thought they were US sensors.

It's ultrasonic on the Mavic Pro. The Mavic 2 uses infrared.

 

[BigAl07]

It's ultrasonic on the Mavic Pro. The Mavic 2 uses infrared.

Thanks bud. Learned something new today

 

[jpzend125]

The autoland mode that you are referring to is ForcedLanding, and it is triggered when VPS height (OSD.sWaveHeight) is less than the parameter HOME.forceLandingHeight and RC_throttle is full down.

You helped me when I crashed my drone into the Hudson River. I have 2 questions on this thread: First, can you explain to a non techie what you are saying in the above post? Second,at what altitude will holding the stick down engage the landing sequence?

 

[bonmot]

You helped me when I crashed my drone into the Hudson River. I have 2 questions on this thread: First, can you explain to a non techie what you are saying in the above post? Second,at what altitude will holding the stick down engage the landing sequence?

Let me give it a try. LOL

Forced landing has nothing to do with the take off location, GPS signal, air pressure sensor, all these fancy stuff.

Only thing it cares about is if there is anything underneath the drone which is being detected by a Infrared distance sensor.

So when it senses something (the ground) it close enough, it will stop descending and hover, if the full throttle down is detected, it will start slow descending, until it hit the ground then stop the motor.

 

[sar104]

Let me give it a try. LOL

Forced landing has nothing to do with the take off location, GPS signal, air pressure sensor, all these fancy stuff.

Only thing it cares about is if there is anything underneath the drone which is being detected by a Infrared distance sensor.

So when it senses something (the ground) it close enough, it will stop descending and hover, if the full throttle down is detected, it will start slow descending, until it hit the ground then stop the motor.

That's a pretty good explanation.