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Questions about Litchi

Discussion in 'Control (Go, Litchi, etc..)' started by Drestin Black, Sep 22, 2016.

  1. Drestin Black

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    OK, the only thing I know about Litchi is something I don't understand so let's say I know next to nothing. PLEASE jump in and correct me if I'm wrong in something I say below.

    What I have seen Litchi used for is to program very long, very far away "Waypoint Missions" - which, as I understand it, is: You program, take off, go here, turn camera and do this there, then go there and then there and then come back here. I was unaware that the Phantom could store commands and execute them on a timed basis. I am making an assumption here because I've seen videos of flights that are crazy long in total distance and range form controller, with plenty of things between take off the drone, and I'm convinced that communications with the controller must be lost during at least portions of the trip.

    Educate me, if you would please; does Litchi upload the entire mission to the drone and then send it off to execute commands at timed intervals? If it doesn't, then what happens when communications with the controller are lost?

    I see that the DJI Go app has the ability to set Waypoints but I haven't looked at it yet. How does that compare to Litchi? I'm expecting that it's similar but Litchi does much more. Like?

    Lastly; other than excellent Way point missions - what else does Litchi do on a Phantom 4 that DJI Go does not?

    Thank you in advance,
    db
     
  2. alokbhargava

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    Yes Litchi loads waypoints mission onto the phantom to execute. In such a case even if the RC gets disconnected, phantom keeps executing the loaded mission. It need not be long distance mission, it could be for short distance too. This feature is quite good for aerial photography as movements and turns and camera angles can be pre determined and can be executed very smoothly.


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  3. Ptr

    Ptr

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    Apart Immersive is worth a shot all you need is $20+ set of VR googles & pop your smartphone in, it auto records which I like & also can screen record your flight, go get you will love
     
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  4. Drestin Black

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    Thank you. I hope you don't mind a few more questions:
    I assume missions can be aborted at any time.
    If, during a mission, you hit low battery warning, what happens?

    When you are programming mission, does it try to keep you from programming a mission too long for expected battery life?


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  5. bkushner

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    You can abort by switching modes. Low battery will have no effect on mission, it will carry out mission until battery runs out. You need to be very careful programming missions. Keep in mind if you have max speed set 33.5 mph and you set the mission to tight, hit some wind and you probably aren't going to make it back.
     
  6. alokbhargava

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    As missions are executed by phantom, it operates under its safety actions such as RTH and smart return during low voltage.

    You should plan so that it returns back in 12-14 minutes. Once you understand details of it, you can go for higher speeds, longer distances and longer durations but all planning should be done by you. Phantom just follows what it is programmed for.


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  7. matti

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    A mission can be cancelled from the Litchi GUI or just by snapping the RC switch to A/P mode. You can also throttle up if some tree is unexeptedly too high for the pre-planned mission. If the AC is disconnected from the RC it will run the mission on its own until it is connected again.

    Triple-check the missions. Be aware of ground elevations. You can use Litchi mission hub on a PC and Google Earth to check the terrain.

    - "Press the "Play" button located in the left button bar to show the mission preflight report. If the mission is valid, you will be able to tap the Go button in the report window to start the mission. When initiated, the AC will rise to 6m altitude if it is below that threshold, then proceed to the first waypoint in a direct path. Make sure there are no obstacles between the AC initial location and the first waypoint. If the AC is grounded when starting a mission, it will only take off if the 'automatic take off' general setting is enabled."

    - Max distance and max altitude DJI GO app settings are respected (there might be a rounding error so while 120m does not work while 110m does).

    - 3D distance between consecutive waypoints (including between last WP and first WP) must be within 0.5m to 2000m (in one mission I had very carefully put the 1st and the last waypoint on top of each other -- apparently this is not allowed for some reason).

    - If you have set end of mission as "Return to Waypoint 1" the last waypoint must be within 2000m of "1".

    - When outside of RC range, Litchi can’t control gimbal angle because the DJI SDK only allows gimbal control if the AC is in contact with the RC. When you lose RC control, the gimbal will stay at whatever angle it is set at. There is a way around this though, but you must use straight lines rather than curved waypoints. You can set a waypoint action to set the gimbal at a particular angle. Problem is, it will stay at that angle until the next waypoint is reached, with a new angle setting. OR just set a specific gimbal angle and continue to use a curved path. Just make sure you have a good guess on the correct angle (or do your trigonomy homework).

    - AFAIK max total length of mission for all waypoints is 10km = 6.2 miles?

    - If the AC loses RC connection it will continue the waypoints.

    - If the AC loses RC and GPS connection (depending on how many satellites left) it hovers and lands when the battery runs out.

    - Litchi will slow down the planned horizontal speed so the AC has enough time time to ascent over an obstacle if the next waypoint is directly above the obstacle (NOT after the obstacle). It will maintain the 3D path by slowing down horizontal speed to reach a programmed altitude. (P3P max speed 16 m/s = 57.6 km/h = 35.8 mph. Max ascent speed 5 m/s = 18 km/h = 11.2 mph, max descent speed 3 m/s = 10.8 km/h = 6.7 mph).

    - Land as a finishing move will currently only execute only under 2km distance due to a bug in the DJI 5/2016 V01.08.0080 FW because it misinterprets that at a certain distance. A workaround is to set waypoints to come back home. So if you want to make a >2km one way trip you will have to make waypoints back home, but try drive to the destination in time to take control.

    - Google Earth path to Litchi Mission Hub:
    Google Earth > Add > Path > Left-click a path > Altitude tab > Relative to ground, set desired AGL Altitude for the AC (with 0m Litchi Mission Hub defaults to 30m AGL) > OK
    > File > Save > Save Place As... > Kml
    Litchi Mission Hub > MISSIONS > Import > Choose File > Import to new mission
    Ground elevations are automatically added to the desired AGL.
    Drawing paths and polygons - Earth Help

    AFAIK Google Earth elevation data might be +/- 15 meters off and it is avaraged to a 90m grid so it might not be very reliable in a hilly terrain.
     
  8. Tom Kriplean

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    Hope this question wasn't answered here already and I missed it...but

    I planned waypoint mission in Google Earth Pro and saved as KML file.

    I imported into Mission Hub and made necessary adjustments. I used relative to ground in Google Earth Pro by the way.

    But now in Mission Hub I can't seem to get "curved turns" to show on the map, even though I have that turned on in Mission settings?

    Any help or guidance would be appreciated.