Skip to content
  • Categories
  • Recent
  • Tags
  • Popular
  • Users
  • Groups
Collapse
Brand Logo

ModalAI Forum

  1. ModalAI Support Forum
  2. Ask your questions right here!
  3. Take-Off and Land command each fly to xy=[0,0] location instead of on the spot

Take-Off and Land command each fly to xy=[0,0] location instead of on the spot

Scheduled Pinned Locked Moved Ask your questions right here!
px4
6 Posts 3 Posters 2.3k Views 1 Watching
  • Oldest to Newest
  • Newest to Oldest
  • Most Votes
Reply
  • Reply as topic
Log in to reply
This topic has been deleted. Only users with topic management privileges can see it.
  • LaborzaubererTHIL Offline
    LaborzaubererTHIL Offline
    LaborzaubererTHI
    wrote on last edited by
    #1

    Dear developers,

    while connected to PX4 instance over MavSDK, using the python environment, we initiate the take-off and land command.
    But instead of the commands being executed on the spot, meaning where the drone is, the drones fly towards its xy=[0,0] location while executing the respectively command. So instead of flying vertical each time, they actually fly diagonal.

    More detailed description:
    Drone position at [1, 0, 0].
    Command takeoff.
    Offboard to setpoint [-2,0].
    Command land.

    April tag #0 is set to “unknown” and no other tag specified.

    Result:
    Took off and flew diagonal to location: NED = [0, 0, -1.5].
    Flew backwards to [-2,0,-1.5] as commanded in offboard mode.
    Land command led to a diagonal land flight at [0,0] location, where it initialy took off from.

    Expected:
    Take-off and land command would lead to vertical flight at the xy-location where it was when initiated.

    The flight can be seen here: https://www.youtube.com/watch?v=Trz97csbsz0

    Our example is very close to your example offboard_position_ned2.py found here:
    https://gitlab.com/voxl-public/voxl-docker-images/voxl-docker-mavsdk-python/-/blob/master/offboard_position_ned2.py?ref_type=heads

    From testing PX4 within an gazebo environment, we did not expect such a behavior.

    Regards
    LabMag

    Drone: RB5
    System-image: 1.7.1-M0052-14.1a-perf-nightly-20231025
    Kernel: #1 SMP PREEMPT Thu Oct 26 05:24:02 UTC 2023 4.19.125
    hw version: M0052
    voxl-suite: 1.1.2

    wilkinsafW 1 Reply Last reply
    0
    • LaborzaubererTHIL LaborzaubererTHI

      Dear developers,

      while connected to PX4 instance over MavSDK, using the python environment, we initiate the take-off and land command.
      But instead of the commands being executed on the spot, meaning where the drone is, the drones fly towards its xy=[0,0] location while executing the respectively command. So instead of flying vertical each time, they actually fly diagonal.

      More detailed description:
      Drone position at [1, 0, 0].
      Command takeoff.
      Offboard to setpoint [-2,0].
      Command land.

      April tag #0 is set to “unknown” and no other tag specified.

      Result:
      Took off and flew diagonal to location: NED = [0, 0, -1.5].
      Flew backwards to [-2,0,-1.5] as commanded in offboard mode.
      Land command led to a diagonal land flight at [0,0] location, where it initialy took off from.

      Expected:
      Take-off and land command would lead to vertical flight at the xy-location where it was when initiated.

      The flight can be seen here: https://www.youtube.com/watch?v=Trz97csbsz0

      Our example is very close to your example offboard_position_ned2.py found here:
      https://gitlab.com/voxl-public/voxl-docker-images/voxl-docker-mavsdk-python/-/blob/master/offboard_position_ned2.py?ref_type=heads

      From testing PX4 within an gazebo environment, we did not expect such a behavior.

      Regards
      LabMag

      Drone: RB5
      System-image: 1.7.1-M0052-14.1a-perf-nightly-20231025
      Kernel: #1 SMP PREEMPT Thu Oct 26 05:24:02 UTC 2023 4.19.125
      hw version: M0052
      voxl-suite: 1.1.2

      wilkinsafW Offline
      wilkinsafW Offline
      wilkinsaf
      ModalAI Team
      wrote on last edited by
      #2

      @LaborzaubererTHI

      What coordinate frame are you using?

      LaborzaubererTHIL 1 Reply Last reply
      0
      • wilkinsafW wilkinsaf

        @LaborzaubererTHI

        What coordinate frame are you using?

        LaborzaubererTHIL Offline
        LaborzaubererTHIL Offline
        LaborzaubererTHI
        wrote on last edited by
        #3

        @wilkinsaf

        We are connected to the drone via MavSDK. We booted the drone at the [0,0] location. Carried it forwards to [1,0] and send the takeoff and land commands via MavSDK.
        Due to the fact that I think we are connected to PX4 I suspect we are using its coordinate system.

        Regards.

        LaborzaubererTHIL 1 Reply Last reply
        0
        • LaborzaubererTHIL LaborzaubererTHI

          @wilkinsaf

          We are connected to the drone via MavSDK. We booted the drone at the [0,0] location. Carried it forwards to [1,0] and send the takeoff and land commands via MavSDK.
          Due to the fact that I think we are connected to PX4 I suspect we are using its coordinate system.

          Regards.

          LaborzaubererTHIL Offline
          LaborzaubererTHIL Offline
          LaborzaubererTHI
          wrote on last edited by
          #4

          @wilkinsaf
          @LaborzaubererTHI

          How would one go about using the different coordinate systems? All of our code is currently running on an external computer, not on the drone. [Question might need separate thread].

          Eric KatzfeyE 1 Reply Last reply
          0
          • LaborzaubererTHIL LaborzaubererTHI

            @wilkinsaf
            @LaborzaubererTHI

            How would one go about using the different coordinate systems? All of our code is currently running on an external computer, not on the drone. [Question might need separate thread].

            Eric KatzfeyE Offline
            Eric KatzfeyE Offline
            Eric Katzfey
            ModalAI Team
            wrote on last edited by
            #5

            @LaborzaubererTHI Sounds like it may be similar to: https://forum.modalai.com/topic/2533/failsafe-landing-bug-in-px4-1-14/19?_=1713800679314

            LaborzaubererTHIL 1 Reply Last reply
            0
            • Eric KatzfeyE Eric Katzfey

              @LaborzaubererTHI Sounds like it may be similar to: https://forum.modalai.com/topic/2533/failsafe-landing-bug-in-px4-1-14/19?_=1713800679314

              LaborzaubererTHIL Offline
              LaborzaubererTHIL Offline
              LaborzaubererTHI
              wrote on last edited by
              #6

              @Eric-Katzfey said in Take-Off and Land command each fly to xy=[0,0] location instead of on the spot:

              @LaborzaubererTHI Sounds like it may be similar to: https://forum.modalai.com/topic/2533/failsafe-landing-bug-in-px4-1-14/19?_=1713800679314

              Indeed it does.

              1 Reply Last reply
              0

              Hello! It looks like you're interested in this conversation, but you don't have an account yet.

              Getting fed up of having to scroll through the same posts each visit? When you register for an account, you'll always come back to exactly where you were before, and choose to be notified of new replies (either via email, or push notification). You'll also be able to save bookmarks and upvote posts to show your appreciation to other community members.

              With your input, this post could be even better 💗

              Register Login
              Reply
              • Reply as topic
              Log in to reply
              • Oldest to Newest
              • Newest to Oldest
              • Most Votes


              ModalAI
              Categories Recent Tags ModalAI.com Docs
              © 2026 ModalAI® · Accelerating autonomy for smaller, smarter, safer drones · Powered by NodeBB
              • Login

              • Login or register to search.
              • First post
                Last post
              0
              • Categories
              • Recent
              • Tags
              • Popular
              • Users
              • Groups