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  3. Mainline PX4 or voxl-px4 bug causing inconsistent Vz and z estimates by EKF2?

Mainline PX4 or voxl-px4 bug causing inconsistent Vz and z estimates by EKF2?

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  • ModeratorM Moderator

    @hmlow there are multiple sets of extrinsics

    if you run voxl-inspect-pose vvhub_body_wrt_local on voxl2 it will apply the extrinsics and output pose that should be inline w/PX4's local position. Please verify those outputs match what px4 is reporting.

    PX4 has its own rotations as well

    H Offline
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    hmlow
    Regular
    wrote on last edited by hmlow
    #7

    @Moderator Yes the extrinsics are correct and the VIO pose matches PX4 EKF2 estimates well except during the segments max velocity rolling maneuvers at 3m/s where VIO and EKF2 Vz and z deviates (but VIO's estimates is correct and matches with visual observation), which is what this post was about in the first place.

    Comparison of x y z between VIO and EKF2 local position estimates:

    d4f2c137-a7db-4c80-b93c-85e5a880b550-image.png

    Comparison of Vx between VIO and EKF2 estimates:

    c2b15ad1-0f4a-4a33-bf7d-28fe1f1f57b0-image.png

    Comparison of Vy between VIO and EKF2 estimates:

    e0c3fa36-7a23-416b-8de6-d0e4023f7fb7-image.png

    Comparison of Vz between VIO and EKF2 estimates:

    e165e6e3-b396-4092-ab17-548e3c6adb83-image.png

    Im attaching the voxl-logger VIO logs and PX4 ulg file here. The 2 files are already time synced so you can plot them directly.

    VIO log
    PX4 log

    Thanks

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    • Cliff WongC Cliff Wong

      Hey there, if you are flying solely with VIO (no GPS), suggest loading our indoor estimator params to add to the current setup on PX4. Outdoor vio+gps is here. These set the vio sensitivity that is in line with the suggestions mention on your PX4 forum's thread. Also we're assuming that extrinsics.conf values have not changed and are same as the factory settings.

      Secondly, if you run voxl-inspect-pose vvhub_body_wrt_local on voxl2 it will apply the extrinsics and output pose that should be inline w/PX4's local position. If those values are correct, then we're looking at a PX4 tuning/config issue (we can still help).

      One thing that looks weird on your PX4 flight log is Roll and Yaw rates are not keeping up w/respective setpoints (noisy). [Hence, thirdly, suggest an] IMU calibration on the PX4 side.

      Lastly in /etc/modalai/voxl-vision-hub.conf there's a parameter called en_reset_vio_if_initialized_inverted. It is set to true as it's to account if vio was accidentally initialized upside down (while carrying the drone for example). You can set it to false and if there's a mismatch on VIO-PX4, you'll see it immediately.

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      hmlow
      Regular
      wrote on last edited by hmlow
      #8

      @Cliff-Wong

      While the logs and graphs above are based on my own customized aircraft, I just tried the same maneuver on the Starling (with shipped params and configured for indoor VIO) and i can confirm that the same observation is repeatable.

      Im curious if you guys would see the same uncommanded climb/sink if you would roll your own Starling aircraft left (or right) for 10 - 20m (3m/s, with CP turned off) and then in the opposite direction. The logs would also show that the EKF2 estimates having the same issues as i have described here and on the github post..

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      • H hmlow

        @Cliff-Wong

        While the logs and graphs above are based on my own customized aircraft, I just tried the same maneuver on the Starling (with shipped params and configured for indoor VIO) and i can confirm that the same observation is repeatable.

        Im curious if you guys would see the same uncommanded climb/sink if you would roll your own Starling aircraft left (or right) for 10 - 20m (3m/s, with CP turned off) and then in the opposite direction. The logs would also show that the EKF2 estimates having the same issues as i have described here and on the github post..

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        hmlow
        Regular
        wrote on last edited by
        #9

        Hi did anyone manage to verify this?

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        • H hmlow

          Hi did anyone manage to verify this?

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          hmlow
          Regular
          wrote on last edited by
          #10

          Any devs?

          I was able to produce this issue on two separate Starlings and a customized 250g drone

          wilkinsafW 1 Reply Last reply
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          • H hmlow

            Any devs?

            I was able to produce this issue on two separate Starlings and a customized 250g drone

            wilkinsafW Offline
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            wilkinsaf
            ModalAI Team
            wrote on last edited by
            #11

            @hmlow I was seeing the same thing on my starling. Have you tried completely disconnecting the GPS/baro unit on top and turning off the parameter HAS_MAG?

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            • wilkinsafW wilkinsaf

              @hmlow I was seeing the same thing on my starling. Have you tried completely disconnecting the GPS/baro unit on top and turning off the parameter HAS_MAG?

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              hmlow
              Regular
              wrote on last edited by
              #12

              @wilkinsaf That solved the issue for you?

              wilkinsafW 1 Reply Last reply
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              • H hmlow

                @wilkinsaf That solved the issue for you?

                wilkinsafW Offline
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                wilkinsaf
                ModalAI Team
                wrote on last edited by
                #13

                @hmlow yes. Ideally you would adjust the EKF2 parameters to increase the gps/mag threshold so they wouldn't affect your local position. But, quick and dirty is to unplug the gps unit. See if that solves your issue. If it does, then worry about EKF2 parameters

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                • wilkinsafW wilkinsaf

                  @hmlow yes. Ideally you would adjust the EKF2 parameters to increase the gps/mag threshold so they wouldn't affect your local position. But, quick and dirty is to unplug the gps unit. See if that solves your issue. If it does, then worry about EKF2 parameters

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                  hmlow
                  Regular
                  wrote on last edited by
                  #14

                  @wilkinsaf actually no, I'm using neither GPS nor mag (disabled both) as my flights are entirely indoors

                  wilkinsafW 1 Reply Last reply
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                  • H hmlow

                    @wilkinsaf actually no, I'm using neither GPS nor mag (disabled both) as my flights are entirely indoors

                    wilkinsafW Offline
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                    wilkinsaf
                    ModalAI Team
                    wrote on last edited by
                    #15

                    @hmlow

                    So, basically the main issue is that in the logs the qvio and ekf2 are reporting different position estimates? But, everything is flying correctly?

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                    • wilkinsafW wilkinsaf

                      @hmlow

                      So, basically the main issue is that in the logs the qvio and ekf2 are reporting different position estimates? But, everything is flying correctly?

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                      hmlow
                      Regular
                      wrote on last edited by hmlow
                      #16

                      @wilkinsaf Flying correctly for the most part yes.

                      Except during specific maneuvers as i have described in my first post (details in the github link) and the third post.
                      Its challenging to summarize the issue in a few lines..

                      wilkinsafW 1 Reply Last reply
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                      • H hmlow

                        @wilkinsaf Flying correctly for the most part yes.

                        Except during specific maneuvers as i have described in my first post (details in the github link) and the third post.
                        Its challenging to summarize the issue in a few lines..

                        wilkinsafW Offline
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                        wilkinsaf
                        ModalAI Team
                        wrote on last edited by
                        #17

                        @hmlow I was flying over the weekend, and saw some inconsistencies as well tbh. The quality of the QVIO was reporting not as high as it was in version 0.9.5 SDK release. I will ask the devs and see what they say.
                        First, I need to compile some logs from voxl-qvio.

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