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

ModalAI Forum

  1. ModalAI Support Forum
  2. VOXL Dev Drones
  3. Sentinel
  4. Sentinel flips during takeoff

Sentinel flips during takeoff

Scheduled Pinned Locked Moved Sentinel
39 Posts 2 Posters 10.0k 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.
  • Eric KatzfeyE Eric Katzfey

    @stevedan A couple of questions. First, are you power cycling the drone in between each of these flight attempts or just landing and then attempting the next flight without a power cycle? Is it always the same motor that appears to not be turning? If so, is it the same motor on the second drone?

    S Offline
    S Offline
    stevedan
    Regular
    wrote on last edited by
    #7

    @Eric-Katzfey yes, it happens on a different motor on the second drone but when it happens on eahc drone, it happens in the same motors

    1 Reply Last reply
    0
    • Eric KatzfeyE Eric Katzfey

      @stevedan Couple more questions. Are you setting the altitude for the mission to be 0.51m? That's pretty low. It could be trying to turn towards the first waypoint before it has even left the ground. Can you try at a higher altitude? What are you using for position control. Doesn't look like you are using GPS.

      S Offline
      S Offline
      stevedan
      Regular
      wrote on last edited by
      #8

      @Eric-Katzfey i am flying indoor. Going high is a bit dangerous. I have done this multiple times on the rb5 without issue.

      1 Reply Last reply
      0
      • Eric KatzfeyE Eric Katzfey

        @stevedan And if you set the parameter UART_ESC_VLOG to 1 then we can see in the logs if the ESC is doing the right thing.

        S Offline
        S Offline
        stevedan
        Regular
        wrote on last edited by
        #9

        @Eric-Katzfey i will log it on Monday and send it.

        Eric KatzfeyE 1 Reply Last reply
        0
        • S stevedan

          @Eric-Katzfey i will log it on Monday and send it.

          Eric KatzfeyE Online
          Eric KatzfeyE Online
          Eric Katzfey
          ModalAI Team
          wrote on last edited by
          #10

          @stevedan A video of a good flight and of a bad one would also be pretty helpful.

          S 1 Reply Last reply
          0
          • Eric KatzfeyE Eric Katzfey

            @stevedan Also, with battery / power removed, can you slowly rotate each motor by hand and see if you can feel any sticky spots? Any unusual noise from the motor when it is being powered?

            S Offline
            S Offline
            stevedan
            Regular
            wrote on last edited by
            #11

            @Eric-Katzfey when I spin the motor slow, it does as shown in the video but spinning it a bit fast, it goes smoothly. No unusual noise when I turn the drone up. Videos are in the same link as before. https://drive.google.com/drive/folders/1tFS2fI25ayHK0pZ4bpmeG1JC0PZRACEX?usp=sharing

            1 Reply Last reply
            0
            • Eric KatzfeyE Eric Katzfey

              @stevedan A video of a good flight and of a bad one would also be pretty helpful.

              S Offline
              S Offline
              stevedan
              Regular
              wrote on last edited by stevedan
              #12

              @Eric-Katzfey I have also added a video to the link and the log file with the name test_flight_UART_ESC_VLOG_fail for the failed flight test and test_flight_UART_ESC_VLOG_sucess for the successful flight test.

              Eric KatzfeyE 2 Replies Last reply
              0
              • S stevedan

                @Eric-Katzfey I have also added a video to the link and the log file with the name test_flight_UART_ESC_VLOG_fail for the failed flight test and test_flight_UART_ESC_VLOG_sucess for the successful flight test.

                Eric KatzfeyE Online
                Eric KatzfeyE Online
                Eric Katzfey
                ModalAI Team
                wrote on last edited by
                #13

                @stevedan Thanks! It's clear from the logs that PX4 is commanding the proper motor speed to the ESC but the ESC is reporting that the motor is spinning much slower than the desired speed until the drone starts to take off. At that point that motor is commanded to go to maximum rpm and then all of a sudden the motor does start spinning at the desired speed. We are discussing this internally and will come up with a recommendation for next steps.

                1 Reply Last reply
                0
                • S stevedan

                  @Eric-Katzfey I have also added a video to the link and the log file with the name test_flight_UART_ESC_VLOG_fail for the failed flight test and test_flight_UART_ESC_VLOG_sucess for the successful flight test.

                  Eric KatzfeyE Online
                  Eric KatzfeyE Online
                  Eric Katzfey
                  ModalAI Team
                  wrote on last edited by
                  #14

                  @stevedan One quick thing you can try is to blow some compressed air through the motor. If there is some debris stuck inside the motor then the air could blow it out.

                  S 1 Reply Last reply
                  0
                  • Eric KatzfeyE Eric Katzfey

                    @stevedan One quick thing you can try is to blow some compressed air through the motor. If there is some debris stuck inside the motor then the air could blow it out.

                    S Offline
                    S Offline
                    stevedan
                    Regular
                    wrote on last edited by
                    #15

                    @Eric-Katzfey I have tried that and it seems not to work. As you said, this happens when during the arming, one of the propellers does not spin fast enough like the others. It happens randomly on both drones.

                    Eric KatzfeyE 1 Reply Last reply
                    0
                    • S stevedan

                      @Eric-Katzfey I have tried that and it seems not to work. As you said, this happens when during the arming, one of the propellers does not spin fast enough like the others. It happens randomly on both drones.

                      Eric KatzfeyE Online
                      Eric KatzfeyE Online
                      Eric Katzfey
                      ModalAI Team
                      wrote on last edited by
                      #16

                      @stevedan Okay, thanks for trying that. We are still discussing internally on best next steps.

                      1 Reply Last reply
                      0
                      • S Offline
                        S Offline
                        stevedan
                        Regular
                        wrote on last edited by stevedan
                        #17

                        @Eric-Katzfey Just adding more information, this also happens sometimes in manual flight, but it take time for the motors to get to speed during arming.

                        Eric KatzfeyE 1 Reply Last reply
                        0
                        • S stevedan

                          @Eric-Katzfey Just adding more information, this also happens sometimes in manual flight, but it take time for the motors to get to speed during arming.

                          Eric KatzfeyE Online
                          Eric KatzfeyE Online
                          Eric Katzfey
                          ModalAI Team
                          wrote on last edited by Eric Katzfey
                          #18

                          @stevedan Okay, thanks! And thanks for your patience. We are locating a drone here in San Diego that exhibits the same behavior so we have a way to reproduce and resolve the issue. One option is to send some new motors but our lead ESC engineer believes he can resolve this with an update to the ESC firmware.

                          S 1 Reply Last reply
                          0
                          • Eric KatzfeyE Eric Katzfey

                            @stevedan Okay, thanks! And thanks for your patience. We are locating a drone here in San Diego that exhibits the same behavior so we have a way to reproduce and resolve the issue. One option is to send some new motors but our lead ESC engineer believes he can resolve this with an update to the ESC firmware.

                            S Offline
                            S Offline
                            stevedan
                            Regular
                            wrote on last edited by
                            #19

                            @Eric-Katzfey Thank you for the fast response. Let us know because there is a bit of urgency to use the drone and there wont be enough time to procure another due to lead time. We currently have 3 new drone and plan to procure more but this is hindering us from doing so.

                            Eric KatzfeyE 2 Replies Last reply
                            0
                            • S stevedan

                              @Eric-Katzfey Thank you for the fast response. Let us know because there is a bit of urgency to use the drone and there wont be enough time to procure another due to lead time. We currently have 3 new drone and plan to procure more but this is hindering us from doing so.

                              Eric KatzfeyE Online
                              Eric KatzfeyE Online
                              Eric Katzfey
                              ModalAI Team
                              wrote on last edited by
                              #20

                              @stevedan Okay, understood. We are testing some new ESC firmware now and hope to have an update for you early next week.

                              S 1 Reply Last reply
                              0
                              • S stevedan

                                @Eric-Katzfey Thank you for the fast response. Let us know because there is a bit of urgency to use the drone and there wont be enough time to procure another due to lead time. We currently have 3 new drone and plan to procure more but this is hindering us from doing so.

                                Eric KatzfeyE Online
                                Eric KatzfeyE Online
                                Eric Katzfey
                                ModalAI Team
                                wrote on last edited by
                                #21

                                @stevedan We will need to walk you through the procedure to update the ESC firmware. In order to do that we need to know what software you have running on the drone now. Can you paste the output of voxl-version?

                                S 1 Reply Last reply
                                0
                                • S Offline
                                  S Offline
                                  stevedan
                                  Regular
                                  wrote on last edited by stevedan
                                  #22

                                  @Eric-Katzfey

                                   Service Name         |  Version  |  Enabled  |   Running   |  CPU Usage
                                  ---------------------------------------------------------------------------
                                   docker-autorun       |    1.2.4  | Disabled  | Not Running |  
                                   docker-daemon        |    1.2.4  | Disabled  | Not Running |  
                                   modallink-relink     |   0.16.1  | Disabled  | Not Running |  
                                   voxl-camera-server   |    1.3.5  |  Enabled  |   Running   |   116.7
                                   voxl-cpu-monitor     |    0.3.0  |  Enabled  |   Running   |     0.0
                                   voxl-dfs-server      |    0.1.0  | Disabled  | Not Running |  
                                   voxl-imu-server      |    0.5.0  |  Enabled  |   Running   |     0.0
                                   voxl-mavlink-server  |    0.3.0  |  Enabled  |   Running   |     0.0
                                   voxl-modem           |   0.16.1  | Disabled  | Not Running |  
                                   voxl-portal          |    0.5.0  |  Enabled  |   Running   |     5.6
                                   voxl-px4-imu-server  |    0.1.2  | Disabled  | Not Running |  
                                   voxl-px4             |  1.12.31  |  Enabled  |   Running   |     0.0
                                   voxl-qvio-server     |    0.8.2  |  Enabled  |   Running   |    27.8
                                   voxl-remote-id       |    0.0.5  | Disabled  | Not Running |  
                                   voxl-softap          |    0.1.5  | Disabled  | Not Running |  
                                   voxl-static-ip       |    0.1.5  | Disabled  | Not Running |  
                                   voxl-streamer        |    0.4.1  |  Enabled  |   Running   |     0.0
                                   voxl-tag-detector    |    0.0.4  | Disabled  | Not Running |  
                                   voxl-tflite-server   |    0.3.1  | Disabled  | Not Running |  
                                   voxl-time-sync       |    1.2.2  | Disabled  | Not Running |  
                                   voxl-vision-px4      |    1.4.0  |  Enabled  |   Running   |     5.6
                                   voxl-wait-for-fs     |    1.2.2  |  Enabled  |  Completed  |  
                                  
                                  
                                  
                                  1 Reply Last reply
                                  0
                                  • Eric KatzfeyE Eric Katzfey

                                    @stevedan We will need to walk you through the procedure to update the ESC firmware. In order to do that we need to know what software you have running on the drone now. Can you paste the output of voxl-version?

                                    S Offline
                                    S Offline
                                    stevedan
                                    Regular
                                    wrote on last edited by
                                    #23

                                    @Eric-Katzfey Is it possible we can set a time that both of us are available to speed up the process given that your timezone is different from mine?. like 6pm spain time?

                                    Eric KatzfeyE 2 Replies Last reply
                                    0
                                    • S stevedan

                                      @Eric-Katzfey Is it possible we can set a time that both of us are available to speed up the process given that your timezone is different from mine?. like 6pm spain time?

                                      Eric KatzfeyE Online
                                      Eric KatzfeyE Online
                                      Eric Katzfey
                                      ModalAI Team
                                      wrote on last edited by
                                      #24

                                      @stevedan Would you be willing to just move to our latest software platform release to resolve this rather than trying to get new ESC firmware setup in the release that you have now? It is in beta but we can give you access to it and it should solve your flipping issue.

                                      1 Reply Last reply
                                      0
                                      • S stevedan

                                        @Eric-Katzfey Is it possible we can set a time that both of us are available to speed up the process given that your timezone is different from mine?. like 6pm spain time?

                                        Eric KatzfeyE Online
                                        Eric KatzfeyE Online
                                        Eric Katzfey
                                        ModalAI Team
                                        wrote on last edited by
                                        #25

                                        @stevedan I sent you a link to the new platform release in email if you are interested in trying it out.

                                        S 1 Reply Last reply
                                        0
                                        • Eric KatzfeyE Eric Katzfey

                                          @stevedan I sent you a link to the new platform release in email if you are interested in trying it out.

                                          S Offline
                                          S Offline
                                          stevedan
                                          Regular
                                          wrote on last edited by stevedan
                                          #26

                                          @Eric-Katzfey I can test this release and see if it solves the problem. When would this release be officially out?.

                                          Eric KatzfeyE 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

                                          • Don't have an account? Register

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