Landing / recovering UAV at speed on a ship

BerndM · Apr 7, 2019

There has been a lot written about how METAL affects the compass calibration of a Mavic. Unless I'm mistaken, your ship is undoubtedly all metal. A whole huge bunch of metal
I would be EXTREMELY hesitant to try to fly off an all steel moving ship and have any expectations on a successful return and landing.
If you do decide to try it, post the video so we can all see

BanditsRoost · Apr 7, 2019

DennisTerpstra said:
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

Not on a ship but have successfully landed in the bed of a moving pickup truck, through the lift gate at a Honda CR-V and off a moving pontoon boat. Landed and took off from the pontoon. That was the easiest if the three. My only real advice is do it in atti mode. Every attempt I made in GPS resulted in broken parts. In GPS mode it stops abruptly and and tries to hover in last coordanance. In atti mode as you let off forward motion, the AC continues to coast forward while you descend in control.

Skry · Apr 7, 2019

Very interesting concept. I have not attempted motion landing but there are few videos on youtube and also some mods that could help. see my comments bellow.

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?
I think its a valid concern. 28 is quite fast and you might indeed be tilted enough to scrap, even more so in you have had wind. if you using phantom perhaps less of a concern.

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.
there was a guy who tried to land on moving pickup track. you can search youtube for it. It was un-successful. conclusion was - as soon as you engage the LANDING the drone will want to stop in its current position. If you have a long deck and attempt lading at the front of the boat, than the drone would stop at its position. it will take few seconds for the drone to land during which your boat would move forward. questions are:
- do you have enough lenght of the deck to allow sufficient time for the drone to land?
- at the touchdown the relative speed difference between moving deck and drone will be 28kmph. if one leg touches the deck first it might spin the drone. at any case there will be some serious sliding involved.

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....
you are saying drone is very powerful. so i suspect it is not Moavic Pro. If it was mavic pro or phantom you could hand catch it (you will need friend to help you). basically you would have to fly flose to your friend while he would need to catch it front leg and belly. Best results are with drone flying behing the boat for small vessels - for your large vessel pethaps you could also try at the deck if its stable enough.
Once your friend holds the drone you could tilt is quicly 90 deg which would shut the engines immediatly, or you could pull the landing stick down and wait second or two for engines to stop.

4/ What happens if the Software fails during flight. Go4 app or Litchi. Do I still have the controls or will disaster strike?
you can control the drone without the phone all together. However you will have no ides where is the drone and no camera streaming. So the only way to bring it back is to look at the drone and how it reacts to your stick movements. if you had head lights on you might be able to point the drone towards you easier and just keep full speed ahead. Personally i think if yo u are starting from a moving boat, and your phone dies - you have very little chance to land the drone. as soon as the drone is more than 100m away you will have hard time to see it, assess which direction its pointing and you will most likely loose it. Best option would be to restart the phone / the app and chase your boat using video streaming from the drone or using the map.

If i were facing your challenge i would probably consider hand catching, there are movied of people doing this quite sucesfully as per the point 3 above.
Alternatively i would consider also the following (i have mavic pro 1, which allows some modifications that could make this easier. not sure what drone you have):

1. install a net and land the drone in a net.for example fly in front of the boat and slow down and let the boat catch your drone in a net. Engines should automatically stop as soon as drone detects the crash (tilted more than 70 degrees i think). have a look on you tube for police drones designed to capture other drones in nets.
2. land using engine cut off (pull both sticks towards eat-ocher and inwards). Standard cut off takes 1 or 2 seconds during which Drone will spin and fly sideways for few meters, before the command kills the engines. There are movies on YouTube of landing on a stretched blanket using this Technic (movies made by the same guy who tried landing on the moving pickup truck). i think you would need to do it above a net as well, otherwise it might end up in hard crash landing.
3. to reduce the spin/sideways drift you can reduce the cut off time to 0.1 second but you would need to downgrade the firmware to old one and also use older version of DJI Assistant to access parameters.

landing on moving platform (failure)

emergency shut of landing (long, standard shut of time)

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

HoozierDroneDaddy · Apr 7, 2019

Drbobk said:
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.

I would think a 300' ship would not be having the same drift with wind or current or swells that at 24 foot boat would, even while moving unless the seas and weather were quite violent. In which case I would probably not be flying a Mavic.

SmileyGC · Apr 7, 2019

DennisTerpstra said:
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

Hi Dennis

Welcome to the Forum.
I have had my M2Z since November and have read the manual many times and watched a lot of tutorials - mainly on YouTube.
As yet I haven't tried what you want to do, but I have thought about it.
Mrmund above has some good suggestions.
With your large open deck, when near the bow, with most of the deck to the stern, aircraft speed matching you ships speed (on the right stick) lower the aircraft towards the front of the open deck (with left stick), then when within 1 - 2 feet, reduce forward speed (to reduce forward tilt) and land. The ship would be moving forward, the aircraft will slow - but you say you have a large open deck, now behind the acraft, so plenty of room for the landing.... even though the ship will be moving and the aircraft won't....

Or.....

attach some fishing line to the drone, with a fishing weight attached to the bottom. The line could be looped throught the battery compartment (M2) and held in place by the battery. You will need to experiment with length below the aircraft and the weight (to avoid swings into the props) when changing direction. I haven't tried it, but expect 1-2 feet long. Then matching the speed of the ship, lower the aircraft towards your catcher, he grabs the line (& weight) then slide their hand up to grab the aircraft. Keeping away from the props.
It will try to pull away if the sensors are on, but once the catcher has a firm hold of the aircraft, kill the engines....

I hope that was of help - Only my opinion though!!

Graham

Mrmund · Apr 8, 2019

musicjeremy said:
There are two main issues that others have noted: takeoff/landing, and mitigating the risk of losing the drone.

For takeoff and landing, I recommend hand launching and hand catching. That way there is no chance the drone will impact the deck. You can hold on to a mavic that is trying to get away. As long as you grip it firmly with gloves to protect against prop contact you will be fine. Just rehearse how you will do it - I definitely recommend a partner to help you with this.

For risk of loss - as others have noted the best thing would be a dynamic home point but apparently that option doesn't exist for RTH anymore. Plus the home point will be out of date instantaneously in any event. So there are two scenarios that we can consider:

1. The drone temporarily loses contact with the remote due to interference near the drone (usually happens when the drone is far away), or just maxing out the range.

In this case, you need the drone to autonomously come back towards you so you can re-establish control. Before you take off, set your RTH point to an intercept course with your ship. The drone WILL overshoot you, but the idea is that you'll be able to re-establish control and cancel RTH. Importantly, you need to re-establish control before the drone reaches the home point and auto-lands in the sea!

2. The remote fails, so you cannot control the drone at all even if it were in range.

Assuming you've set RTH per the above, you are going to need to get your ship underneath the drone's home point so that you can intercept it and have it land right on the ship. Obviously that is going to be really difficult and the chances of the drone surviving this failure scenario is very very low.

In summary, setting RTH for an intercept course with the ship's course should cause the drone to fly back towards you, allowing you to re-establish control once the interference has cleared. It won't protect you against complete control failures where the aircraft has to auto-land without further inputs.

If DJI had the option to RTH and then hover (vs RTH and then land), that would be the best option as you might be able to stop the ship underneath the hovering drone. But either way, I think scenario #2 is pretty much guaranteed to result in the loss of the drone. Scenario #1 seems risky but manageable.

My philosophy about my drone is that I have already gotten my money's worth having shot hundreds of images that I could not have gotten any other way. So I am willing to risk the drone (not others around me of course) to continue to get these shots.

This is all of course based on the premise that altering your ship's course would have undesirable consequences or would be simply impractical.

"set your RTH point to an intercept course with your ship"
How is this done? I'd love to know, I fly off boats sometimes myself.

brettbrandon · Apr 8, 2019

Anybody notice that this is the OP's first post and he has not been back?

MAvic_South_Oz · Apr 8, 2019

ayyyye, he may be at sea, yaaarrrr

kilomikebravo · Apr 8, 2019

I hope he isn't sea sick.

lamourj3 · Apr 8, 2019

Hi, what about if you fly your drone ahead of the moving ship and slowly decrease your speed until you match the ship speed and try to land, if you do it slowly enough the rotors my not touch the deck

roflyer · Apr 10, 2019

After I saw this video, I believe what Cpt Dennis wants is pretty easy!!!!

Skry · Apr 10, 2019

roflyer said:
After I saw this video, I believe what Cpt Dennis wants is pretty easy!!!!

jezzus - looks like he catches it with his face . hand catching i think still the best option. not sure it would be that smooth with mavic though

msenjur · Jun 6, 2019

will arris raptor2 skid be strong enough that will hold catching during fly?

Like in upper video, but phantom has such sledges integrated...

Thomas B · Jun 6, 2019

brettbrandon said:
Anybody notice that this is the OP's first post and he has not been back?

Probably lost his drone!

AMann · Jun 6, 2019

brettbrandon said:
Anybody notice that this is the OP's first post and he has not been back?

Thomas B said:
Probably lost his drone!

He’s probably somewhere crossing the North Atlantic and is rather busy. But if the MV Fairlift is his ship, he’s going to have difficulty calibrating his compass on it. But if it works for him, the view will be spectacular with the cranes and all.

An interesting description of his work that he wrote :