Landing / recovering UAV at speed on a ship

[DennisTerpstra]

Good day,

I'm a captain on a 110 meters (360 feet) long ship. The vessel is 20.70 meters ( 68 feet ) wide and has a nice open deck the size of an aircraft carrier.

Im using my drone often making spectaculair footage at sea around the world. But this is always done with the vessel stopped. Now Im studying the possibility of shooting my vessel in full motion. She does 15 knots which is about 28 km/h at full speed. Im experienced enough in drone flying to know it's possible. Especially on such a large vessel. But I have a few unanswered questions which I cant solve by reading other threads.

1/ If I match the speed of my vessels 15 knots and come in for a landing the drone is tilted forward. Im afraid the propellors might start scraping the deck or cause problems when landing. Any experience on this matter?
2/ If I stop pushing forward on the controls the drone probably goes in hover mode keeping GPS position. ( Vision systems all off ). This is probably a big problem for safe landing. So are there people who have experience landing on a relatively fast moving object.
3/ Handcatching the drone...(Using leather welders gloves ). Can i power down the motors whilst keeping forward speed on the right stick? I can imagine if I only power down, the drone will try to hold GPS position and will try to escape from the catching hand for a few seconds. The drone is very powerfull so this might be a risk. So what happens during these few seconds you power off the motors whil holding it in a hand AND moving at 15 knots....
4/ What happens if the Software fails during flight. Go4 app or Litchi. Do I still have the controls or will disaster strike?

Anyone who has good experience with this very particular technique of landing a drone on a relatively fast moving object please share your tips and tricks. I really like to be well prepared before I risk ditching a huge investment into the ocean.

Brgds,
Dennis

 

[brett8883]

Good day,

I'm a captain on a 110 meters (360 feet) long ship. The vessel is 20.70 meters ( 68 feet ) wide and has a nice open deck the size of an aircraft carrier.

Im using my drone often making spectaculair footage at sea around the world. But this is always done with the vessel stopped. Now Im studying the possibility of shooting my vessel in full motion. She does 15 knots which is about 28 km/h at full speed. Im experienced enough in drone flying to know it's possible. Especially on such a large vessel. But I have a few unanswered questions which I cant solve by reading other threads.

1/ If I match the speed of my vessels 15 knots and come in for a landing the drone is tilted forward. Im afraid the propellors might start scraping the deck or cause problems when landing. Any experience on this matter?
2/ If I stop pushing forward on the controls the drone probably goes in hover mode keeping GPS position. ( Vision systems all off ). This is probably a big problem for safe landing. So are there people who have experience landing on a relatively fast moving object.
3/ Handcatching the drone...(Using leather welders gloves ). Can i power down the motors whilst keeping forward speed on the right stick? I can imagine if I only power down, the drone will try to hold GPS position and will try to escape from the catching hand for a few seconds. The drone is very powerfull so this might be a risk. So what happens during these few seconds you power off the motors whil holding it in a hand AND moving at 15 knots....
4/ What happens if the Software fails during flight. Go4 app or Litchi. Do I still have the controls or will disaster strike?

Anyone who has good experience with this very particular technique of landing a drone on a relatively fast moving object please share your tips and tricks. I really like to be well prepared before I risk ditching a huge investment into the ocean.

Brgds,
Dennis

15 knots is WAY too fast to do this In my opinion. It was tough when I tried at 8 MPH. really tough. It’s a really risky operation. Way harder than I thought it would be. I didn’t have as much open space and therefore margin of error as you do so it might be easier but keep in mind especially out at sea that the wind can play a significant factor.

I do not reccomend this at that speed. If you are like me and need to try for yourself trust me do it at a much slower speed first to get a feel for how difficult it is and then decide if you want to try it going faster.



When it gets close enough just grab that baby and don’t let go! Left hand on the remote and right hand to catch the drone. When you have it secured in your hand left stick down till it cuts the motors. Takes maybe 2 seconds.

Also remember to set your homepoint as a “dynamic homepoint.”

Yes if you take your hand off the control it will stop relative to the earth. You can modify it to use Atti mode which will be realitive to the air not the earth but if that would help or hurt I’m not sure.

You should have control of it as long as you have radio signal with it. Setting the dynamic home point as stated above will help if you lose radio control with it it will come back to your device which needs to have GPS capability and signal, internet not required. This is really meant to update the homepoint as you move from one location to the next and not as a “moving target” but it should help in an emergency get it to come back closer to your location and then take over manually.


again I can’t reccomend this it’s a huge risk maybe impossible at that speed.

 

[CarlStarke]

I definitely want to see some of these videos, please post link.

 

[Thealien]

I think you could do it with 2 people. 1 flying and 1 catching. It will have to be plucked out of the air. I do not believe there is any way to have it match or hover the speed the vessel is traveling at. Once caught just flip it upside down and it will shut down on its own? My thoughts anyway. If you try please have someone film to share with us (and maybe Americas funniest videos?).

 

[tcope]

First, you stand a good chance of damaging or losing the drone.

You want to set RTH to _hover_. If you loose connection you will need to turn the boat around and regain your connection or sit under the drone for it to land at 10%. If you want to catch on a moving boat I'd recommend setting up a net or have someone throw a large towel over the drone. Don't try to hand catch, you will only knock the drone so it goes and slams into something or someone.

Again, very good chance this will result in a lost or damaged drone.

 

[brett8883]

First, you stand a good chance of damaging or losing the drone.

You want to set RTH to _hover_. If you loose connection you will need to turn the boat around and regain your connection or sit under the drone for it to land at 10%. If you want to catch on a moving boat I'd recommend setting up a net or have someone throw a large towel over the drone. Don't try to hand catch, you will only knock the drone so it goes and slams into something or someone.

Again, very good chance this will result in a lost or damaged drone.

I would highly recommend against changing RTH to hover. Like I said above setting a dynamic homepoint is what you want to do here. Setting it to hover seems counter intuitive. If he looses radio then the drone will stay in the place it lost radio as he is sailing away.

 

[tcope]

If he looses radio then the drone will stay in the place it lost radio as he is sailing away.

What do you think will happen with dynamic RTH?

The home point will be updated every 15' or so. When the OP loses connection the Mavic will fly about 15' backward. By that time, the boat will be about 300' ahead of that point and moving away. What will happen at this point?

 

[brett8883]

What do you think will happen with dynamic RTH?

The home point will be updated every 15' or so. When the OP loses connection the Mavic will fly about 15' backward. By that time, the boat will be about 300' ahead of that point and moving away. What will happen at this point?

Well at least it’s gonna be heading back in his direction rather than staying put. It’s not perfect but I would think it’s better then doing nothing. If he loses connection while it’s in front of the boat at least it will ascend to get out of the way and that also probably gives him better chance of connection since it will be higher and better chance of reconnection.

 

[tcope]

Well at least it’s gonna be heading back in his direction rather than staying put. It’s not perfect but I would think it’s better then doing nothing.

It is going to move 15' back in its flight path rather then stay where it lost connection. Most likely this will be 15' in the _wrong_ direction. What happens once the Mavic returns to the home spot upon losing a connection? That is, if it is not set to hover.

 

[brett8883]

He would need to cancel RTH once he regains control. While I don’t think it’s meant for landing on a moving homepoint, it is meant for a moving operator like in active track. I just see it a a lesser of two evils. Keep the drone where you know it can’t get reception or try to move it somewhere, anywhere but where you know there’s no hope of getting in back

 

[Torcan]

Reading these posts, seems like you would get one chance to get the drone back, and for me that would be launching from the bow and hoping to catch it at the stern before it goes on it's merry way, if you miss, then it is possible the drone would never be able to catch up to the moving ship and you would just sail off leaving it to slowly disappear. 15 knots is a good speed, not sure if the drone could match, especially with wind factor

Remember guys, it's a ship not a private craft, no chance of turning and chasing it.

 

[Mrmund]

Now for the record I haven't tried this but if I was going to I'd try it like this:
2 person operation
Fly alongside ship
Set speed to match
Roll sideways over deck
Left stick down all the way to your partner's gloved hands(also eye pro just in case).
Partner hangs tightly to aircraft until motors stop
I've successfully hand caught my Spark and Mavic Air from a small sailboat but needed a "catcher" to grab it.
I think won't be as hard as these guys do, the SOG won't make a difference if you can match the relative speeds of the aircraft and ship.
Don't forget to take into account any rigging, towers, wheelhouse, ect.
Might want to turn off downwards sensors too.

edit: Also propeller guards would be a good idea when you first try

 

[Meta4]

Also remember to set your homepoint as a “dynamic homepoint.”

I would highly recommend against changing RTH to hover. Like I said above setting a dynamic homepoint is what you want to do here. Setting it to hover seems counter intuitive. If he looses radio then the drone will stay in the place it lost radio as he is sailing away.

Except the DJI Go 4 app doesn't have a dynamic home point.
You can't change RTH to hover.
You can set the loss of signal options to hover.

The biggest issue is that you don't want the drone returning to where it was launched when the battery level is getting low for that didtance.
Simply resetting the home point either to the drone's or the controller's current location every few minutes will prevent that.

 

[tcope]

Except the DJI Go 4 app doesn't have a dynamic home point.
You can't change RTH to hover.
You can set the loss of signal options to hover.

RTH Dynamic Homepoint should become an option when in Active Track. It is available on the DJI Go 4 app. has been for about 2 years now. It was missing since the Phantom 2 but was added back in.

You set Hover under the RTH setting. Don't blame me for DJI's poor app design.

 

[Meta4]

RTH Dynamic Homepoint should become an option when in Active Track. It is available on the DJI Go 4 app. has been for about 2 years now. It was missing since the Phantom 2 but was added back in.

It's available only with Active track but not for general flight.

You set Hover under the RTH setting. Don't blame me for DJI's poor app design.

The only thing you can set for RTH is the RTH height.
Hover is one of the options that can be set as a Loss of Signal action
RTH is the other option that's available.

 

[tcope]

The only thing you can set for RTH is the RTH height.
Hover is one of the options that can be set as a Loss of Signal action
RTH is the other option that's available.

You are 100% correct. RTH has altitude settings and Signal Lost has RTH and Hover as options.

To go back to my original post, when following something, you want to set RC Signal Lost to Hover (not RTH). What I should have said is, change RTH to Hover (under Signal Lost). RTH is the default.

 

[bliksem]

I know people who do this with Phantoms, easier to grab a leg.
Maybe try landing gear (those leg extensions) and land on deck, the extensions will prevent the blades hitting the deck.

 

[Drbobk]

There are some aftermarket floats and landing gear extensions that might raise the aircraft enough that the forward tilt wouldn’t result in a prop strike on the deck. But if the drone was still in POS mode, I think that trying to return it to a level attitude might cause it to try to hold position and therefore drift/skid backwards until power was cut. I guess the approach has to be done in ATTI mode.

Good luck! I’ve landed my Inspire on a 24 ft boat, and every time I was about to set it down the boat would drift with wind or current or swells, and it wasn’t as easy as I expected. I thought I would try it with the boat moving next time, but I hadn’t thought it through as thoroughly as you have.

 

[crlmjohnson]

My question is Why? Just stop the ship. it is already going to be a little hard, even while the ship is stopped, because of water. (GPS) It is not like you are at war or attacking something.
But anyway, I still would like to see the videos after your mission.

I built a custom landing pad for my drones, it is six inches off the ground, pretty large pad...but in a windy conditions my drones do rock a little while I trying to land them on it. I have had several incidents and busted up a few blades, in windy conditions.

good luck!

 

[Bobvt]

Lots of really good suggestions here, here's one more,have you ever watched the DRL,(drone racing league)make a big catch net and just fly it right in to it.
Good luck