Litchi Waypoint Mission -- a couple of scary experiences that have made me much more weary!

[SoundByte]

Autopilot and GO apps can't upload a mission to fly 100% autonomous like Litchi. They have no choice but to RTH or hover in place upon signal loss. That's what sets Litchi apart from all others.

However I also think adding an AUTO RTH option in Litchi for those that expect to always have a control connection is good suggestion.

Not true, Autopilot gives you a choice of flying with the DJI SKD or it's own custom controller. This was implemented in the last update. LCMC is not unique to Litchi, but is part of the DJI SKD. It also allows the importing of KML/KMZ files.

Edit: I would guess most people started using Litchi because it cost less. It is true that is uses LCMC, however I'm willing to bet that, in the beginning, it was discovered after the purchase. Now it's considered a selling point. Autopilot used to sell autonomous modes as in-app purchases, but not anymore. Now they are included in the purchase price. All they have to do now is make it easier to use, but they're working on it.


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[Hangar]

Not true, Autopilot gives you a choice of flying with the DJI SKD or it's own custom controller. This was implemented in the last update. LCMC is not unique to Litchi, but is part of the DJI SKD.

This is correct. Autopilot introduced LCMC in v3.5 on June 20th.

I'm sure most wouldn't use it, but I don't think you can have too many options in a software package.

While there are legal and safe times and places to use LCMC, most of the examples we have seen are from users that are clearly and willingly ignoring the law and safety concerns. Despite this fact, we introduced LCMC anyway as we believe it is the personal responsibility of each user to use Autopilot in a safe and legal way. Having said that, our flight data shows that the vast majority of people agree with us. That is, less than 1% of flights in Autopilot have LCMC enabled.

 

[Mainshipper]

I have been flying my P3P using Litchi waypoint while spending our summer on our boat cruising the remote areas of Ontario's Georgian Bay and North Channel and have been totally satisfied with the way that app functions. I had tested it at home in Florida and was mostly confident it would work but that was over dry land. Up here it's mostly over water and/or jungle so getting it back is important. On my second mission up here I had the dreaded "disconnected" message for almost five minutes and felt like all was lost until it popped up on the map and showed it was continuing on the mission course heading back to me. I believe the main reason was I lost a good signal line of sight due to a tree line. From that point on I understood how that worked and was glad it did. With all this experience I do the following:

1) Plan my missions to be no more than 3 miles (roughly 15 minutes at 14 mph). In most cases my battery is at 40-50% when the mission ends.

2) Fly at 200-300 feet if trees are present. Double check all waypoint settings to make sure that each one is set to the desired altitude for the surrounding terrain.

3) Always start with a fresh, fully charged battery.

4) I now load and start my missions from the ground versus from a hover and have been successfully landing it on a 2x2 cabin hatch on the deck.

 

[Jojoned]

If you've lost communication, you cannot communicate. That means you cannot initiate RTH. There's nothing stupid about it.

If you're proposing that Litchi add some kind of option to auto-RTH after losing signal, that's different.

If you hit RTH while in 'disconnected' mode or lost signal, the mission will continue and then RTH as soon as the connection is reestablished. I intentionally fly Litchi for that purpose to record areas that are out of direct LOS, mostly lakes in mountain country, and I just make sure my RTH height is well clear of straight line returns. I must admit my first Litchi mission was the most stressful 10 minutes, but she came back! and has done so each time. I tested the RTH on purpose to see what it would do..good to know.

 

[SoundByte]

If you hit RTH while in 'disconnected' mode or lost signal, the mission will continue and then RTH as soon as the connection is reestablished. I intentionally fly Litchi for that purpose to record areas that are out of direct LOS, mostly lakes in mountain country, and I just make sure my RTH height is well clear of straight line returns. I must admit my first Litchi mission was the most stressful 10 minutes, but she came back! and has done so each time. I tested the RTH on purpose to see what it would do..good to know.

There are as many ways to use Litchi as there are ideas in ones mind. Do & don't lists abound for insuring that the drone makes it home safely. That being said, the issue at hand is not weather you can fly a Litchi mission and get your bird back safely; we all know you can. But rather, should they have provided the pilot with a "lost R/C RTH" option. I for one, think they should.

 

[SoundByte]

This is correct. Autopilot introduced LCMC in v3.5 on June 20th.


While there are legal and safe times and places to use LCMC, most of the examples we have seen are from users that are clearly and willingly ignoring the law and safety concerns. Despite this fact, we introduced LCMC anyway as we believe it is the personal responsibility of each user to use Autopilot in a safe and legal way. Having said that, our flight data shows that the vast majority of people agree with us. That is, less than 1% of flights in Autopilot have LCMC enabled.

That's probably do to the fact that the best features of autopilot require the use of the custom controller. Litchi's capabilities pale in comparison to what you can do with Autopilot. I use Litchi for "ham & eggs" missions and use Autopilot when I want "beef Wellington"

 

[Pharm]

Litchi offers the option to pause a mission IF it's connected to the RC. If it loses contact, it'll continue the mission and you'd better hope you checked your elevations and adjusted your altitude accordingly before uploading the mission. I recently had to add 160 ft to one of my waypoints prior to starting so I'd clear a hill. It all comes down to knowing your equipment, knowing your software, careful planning, and attention to detail.

 

[Rlisch]

Just my 2 cents,
using FPV Camara Smart RTH works very well with DJI GO turned off bringing the P4 home with enough power to spare for a safe landing just in case.
In the first screen shot you can see the sharp turn close to the triangle mark where the mission was ended by the SRTH feature at 66% charge arriving home with 24%. The quad had approx. 12mph tailwind going out the 5km to the Island. The planned mission was supposed to go close the power plant and then back home.
In the second screen shot from today I just plotted a course of 50,000' around Home to see what happens and in this case, beeing much closer to home, with 18% power left the mission was finished early by the SRTH feature at the sharp turn close to the triangle and the P4 landed with 15% charge left.

 

[Fdnyfish]

If your worried about RTH, than use the DJI GO app. So you want to cripple litchi to do a RTH , you gave DJI go for that

 

[SoundByte]

If your worried about RTH, than use the DJI GO app. So you want to cripple litchi to do a RTH , you gave DJI go for that

You're not making any sense. Who's talking about crippling Litchi? We're talking about adding function, not taking it away.

 

[NoWheels498]

I think the option should be: At loss of signal engage the RTH after completing "x" number of waypoints.

I use litchi to film those area's that it out of range like many others.


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[Dirty Bird]

I can only speak for myself but I use Litchi because I KNOW I'm sending the bird beyond RC range. Otherwise I'd just fly the mission manually.

I think you'll find that that majority of users do NOT use Litchi when loss of radio link is a possibility. I could be wrong, but based on what I have read over various forums, most users do not like this rather scary feature.

 

[Dirty Bird]

It's true. Smart-RTH will cause a Litchi mission to abort & the aircraft to return home. Unfortunately it is overly conservative in its calculations and often aborts needlessly. Best advice is learn your bird's range, be mindful of winds, & fly accordingly.

With a good battery in winds <10 mph you can easily do 35,000' missions @ 30 mph.

Though this is not quite the solution you're looking for but, it may help. I've never tried it. Take a look at the setting SMART RETURN HOME in the DJI Go app. If its ON, then when running a Litchi mission if the battery drops to a certain critical level, it will allegedly execute a RTH. I've heard it was not unusual for this feature to kick in prematurely from time to time. I believe I read this flavor of experience encountered by someone in this forum. You'll have to research more as since I'm just repeating info and could be misspeaking.


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[Jorge Flora]

Litchi is an SDK app.
Can make a better use of many options or features already present on the firmware, but not implement new ones.
Any and every funtion on Litchi is already present, although maybe not used, or maybe implemented in a diferent way, in the GO app.
DJI gives NO OPTION to interrupt any kind of autonomous mission ONCE RC CONTACT IS LOST, except on battery issues.
Once started, the goal is to finish. And there is no way to overcome this, unless modified on the firmware. Smart RTH was an aproach, mainly to correct situations where the Phantom would hover until exaust the battery, and/or land.
In a waypoint mission, Litchi acts exactly as DJI GO would, except that you can program the waypoints without prevously fly to each one. The whole mission is uploaded to the drone, and once started, firmware takes control. You can do whatever you want during the mission, including abort, modify some parameters, or RTH, but ONLY if you have RC contact...
With Litchi (but not with DJI GO), one can program waypoints far beyond RC range. There is some danger involved, and either you accept it or use the app with much precaution.
One way or another, my advice would be to have full knowledge of the batery / drone and app capabilities before using Litchi.
In doubt, at least keep Smart RTH enabled. It's a safety feature: beter lose a mission and have to reconfigure it, than lose the drone, right ?

 

[GFields]

I recently attempted a Litchi Waypoint Mission that I had already set up on my computer at home.

The first thing I noticed, but didn't realize, is that it's entirely possible to load up a mission and simply hit the Play button on the tablet, and watch the drone take off from the ground and begin its mission automatically. Not a cautionary observation, just a pretty cool feature that I wasn't aware of (although in hindsight I guess it's good to be aware of your surroundings to ensure that this type of automation won't lead to a collision, or just launch the drone manually first).

The second thing that happened was that once the drone got about 1.5 km away from me (not going to convert to miles, sorry), the signal became weak, and I lost the RC connection, which I wasn't expecting as I had a very clear line of sight (and normally I don't lose the connection until a fair bit further away in such conditions). I was already aware that in Litchi, the drone will complete its mission even if you lose the signal, and this freaked me out a bit as I wasn't 100% certain that I had set the altitude high enough to clear the ridges coming off the hill I had set as a Point of Interest.

So I opened up the DJO Go app, and for some reason, this app was able to get a (weak) connection, and thankfully I was able to activate RTH (not sure if I could have just done that regardless in the Litchi app?).

Once the drone returned home, I set up a very small and close mission to see how it behaves once you turn off the RC. Sure enough, it continues to complete the mission. I cannot understand why Litchi does not give you the option to abort the mission if the signal is lost, and RTH! It just seems incredibly stupid to me.

Another thing that was rather alarming during this test mission, was that the drone starting to hover erratically in place, and would not move, and it looked like it was caught in some weird turbulence. I panicked and aborted the mission. Much later, it occurred to me that it was doing this because the sun was quite low in the sky and was shining into it, which was perceived to be an obstacle and so the drone wouldn't move forward because its forward obstacle avoidance was switched on. According to the Litchi manual, if the drone's battery reaches the critical level during a mission and there is no RC connection, it will simply land right where it is at the time. It is therefore possible for the drone to get "stuck" with no RC connection when the sun is shining into it, reach its critical battery level, and descend into trees or other obstacles and get destroyed and/or completely lost.

So from now on I am going to be much more weary of how I use Waypoint Missions. I will not do them unless I can see the drone at all times, or I am 100% confident that it will clear all obstacles and the sun won't shine into it (and I don't think that switching off forward obstacle avoidance is a very good solution unless the drone remains in sight at all times).

Are there any other steps I can take to overcome these limitations?

You have every right to be concerned about the Litchi app when using a waypoint mission! Some have reported that (although enabled in the DJI Go app), that the obstacle avoidance system does NOT work (even in P mode). Although Litchi denies this to be the case, I had my first P4 crash using Litchi's app flying a waypoint mission. I have manually flown much of this flight plan manually in the past, but like you, created a waypoint mission using the mission hub. The entire flight was to be 12 minutes. After that time had expired, I went searching for the drone and sure enough, it had crashed onto the bridge I was flying over. The part of the plan I had manually flown over assured me I had plenty of altitude. But apparently the bridge went up at a certain point and the drone was not high enough and flew into a beam on the bridge. The good and the bad: The good thing is it crashed onto the bridge not the river. The bad: The video file was damaged and I have no way of knowing what part of the bridge it hit. The crash should have NEVER occured if the obstacle avoidance was wrorking. (I never enable "fly backward"). Furthermore, trying to contact Litchi is impossible. If anyone has success in contacting them, I would be interested in knowing how.