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  4. "Serial Port Closed!" and other HITL Errors

"Serial Port Closed!" and other HITL Errors

Scheduled Pinned Locked Moved Starling & Starling 2
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  • L labkit

    @Eric-Katzfey Yes, I start px4 with voxl-px4-hitl. Here's the results of the qshell dsp_hitl status command called on the PX4 command prompt after SSHing to the Starling. I assume all the values are set to 0 because the "Serial port closed!" error is preventing Gazebo from sending it data.
    648ca809-0c96-4685-aea4-9608e9482c86-image.png
    On the laptop, I used Docker's virtual file sharing to share /tmp/.X11-unix with docker, so the original GUI mode error seems to be resolved. (The one in which it couldn't acess that directory.)
    4184bf49-8064-47c0-b913-3b83b18771c5-image.png
    By using your instructions, I can get to the docker command prompt in both GUI and headless modes. However, /dev/ttyUSB0 is not present here, although it can still be found from the Linux command line. Running Gazebo from the Docker command line still results in the serial port closed error.

    Here's the attempt to run in GUI mode. Headless mode has the same issue.
    f62ae7fa-7f3e-46fb-9128-1e42f037f8e5-image.png

    Eric KatzfeyE Offline
    Eric KatzfeyE Offline
    Eric Katzfey
    ModalAI Team
    wrote on last edited by
    #6

    @labkit Maybe a groups / permission issue? Here's some more information from my setup:

    root@modalai-XPS-15-9570:/usr/workspace/voxl2_hitl_gazebo# ls -l /dev/ttyUSB0
    crw-rw---- 1 root dialout 188, 0 May 31 16:01 /dev/ttyUSB0
    root@modalai-XPS-15-9570:/usr/workspace/voxl2_hitl_gazebo# groups
    root
    root@modalai-XPS-15-9570:/usr/workspace/voxl2_hitl_gazebo# exit
    exit
    modalai@modalai-XPS-15-9570:~$ ls -l /dev/ttyUSB0
    crw-rw---- 1 root dialout 188, 0 May 31 09:00 /dev/ttyUSB0
    modalai@modalai-XPS-15-9570:~$ groups
    modalai adm dialout cdrom sudo dip plugdev lpadmin lxd sambashare docker
    modalai@modalai-XPS-15-9570:~$ 
    

    Perhaps you need to be in dialout group?

    L 1 Reply Last reply
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    • Eric KatzfeyE Eric Katzfey

      @labkit Maybe a groups / permission issue? Here's some more information from my setup:

      root@modalai-XPS-15-9570:/usr/workspace/voxl2_hitl_gazebo# ls -l /dev/ttyUSB0
      crw-rw---- 1 root dialout 188, 0 May 31 16:01 /dev/ttyUSB0
      root@modalai-XPS-15-9570:/usr/workspace/voxl2_hitl_gazebo# groups
      root
      root@modalai-XPS-15-9570:/usr/workspace/voxl2_hitl_gazebo# exit
      exit
      modalai@modalai-XPS-15-9570:~$ ls -l /dev/ttyUSB0
      crw-rw---- 1 root dialout 188, 0 May 31 09:00 /dev/ttyUSB0
      modalai@modalai-XPS-15-9570:~$ groups
      modalai adm dialout cdrom sudo dip plugdev lpadmin lxd sambashare docker
      modalai@modalai-XPS-15-9570:~$ 
      

      Perhaps you need to be in dialout group?

      L Offline
      L Offline
      labkit
      Contributor
      wrote on last edited by
      #7

      @Eric-Katzfey Here are my results with the same commands.
      3813ac9f-e1a7-4cf5-b0ad-676ba54ddae4-image.png
      I ran docker in the dialout group but it didn't seem to make a difference. I was already in root.
      afc14ddb-b217-4e86-a6b5-65ea8a3edcab-image.png
      As you can see, much of the contents of /dev is missing in docker compared to what's available from the linux command line. It's not only ttyUSB0.

      L 1 Reply Last reply
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      • L labkit

        @Eric-Katzfey Here are my results with the same commands.
        3813ac9f-e1a7-4cf5-b0ad-676ba54ddae4-image.png
        I ran docker in the dialout group but it didn't seem to make a difference. I was already in root.
        afc14ddb-b217-4e86-a6b5-65ea8a3edcab-image.png
        As you can see, much of the contents of /dev is missing in docker compared to what's available from the linux command line. It's not only ttyUSB0.

        L Offline
        L Offline
        labkit
        Contributor
        wrote on last edited by
        #8

        I got Docker to avoid the error by doing the steps in the tutorial in a different order with setup on the drone coming first. This must have been why I didn't receive the "serial port closed" error when I first tried to set up the simulation two days ago. However, I don't think the simulation is in shape to run yet, all I've managed is to get back to where I was originally....

        L 2 Replies Last reply
        0
        • L labkit

          I got Docker to avoid the error by doing the steps in the tutorial in a different order with setup on the drone coming first. This must have been why I didn't receive the "serial port closed" error when I first tried to set up the simulation two days ago. However, I don't think the simulation is in shape to run yet, all I've managed is to get back to where I was originally....

          L Offline
          L Offline
          labkit
          Contributor
          wrote on last edited by labkit
          #9

          @Eric-Katzfey I have figured out why I thought that the drone wasn't giving me a "Serial port closed!" error a couple of days ago but has been doing so yesterday and today. When the gazebo docker container has not been created, the first attempt to create it will result in a "Serial port closed!" error. However, when the container is already running, future attempts to create it will not display the error, they will simply show the following message rather than creating a new container. At first I thought that this message meant that the connection to the drone had successfully avoided the "serial port closed" message.
          708d8de9-27a5-40fb-993a-bb68b0248fff-image.png

          The bad news is that this means that there may never have been a successful connection between the laptop and drone at all. A hardware misconfiguration can't be ruled out in this case. As I said, I had to remove a connection to the ESC 4 in 1 in order to connect the cable to the JST port on the VOXL2. If the connection's in the right place, it might be a permissions issue like you mentioned, although docker was run as privileged and I'm already in dialout.

          7d80004c-f34b-41fb-8e3f-3a17e6194dcb-image.png

          VinnyV 1 Reply Last reply
          0
          • L labkit

            @Eric-Katzfey I have figured out why I thought that the drone wasn't giving me a "Serial port closed!" error a couple of days ago but has been doing so yesterday and today. When the gazebo docker container has not been created, the first attempt to create it will result in a "Serial port closed!" error. However, when the container is already running, future attempts to create it will not display the error, they will simply show the following message rather than creating a new container. At first I thought that this message meant that the connection to the drone had successfully avoided the "serial port closed" message.
            708d8de9-27a5-40fb-993a-bb68b0248fff-image.png

            The bad news is that this means that there may never have been a successful connection between the laptop and drone at all. A hardware misconfiguration can't be ruled out in this case. As I said, I had to remove a connection to the ESC 4 in 1 in order to connect the cable to the JST port on the VOXL2. If the connection's in the right place, it might be a permissions issue like you mentioned, although docker was run as privileged and I'm already in dialout.

            7d80004c-f34b-41fb-8e3f-3a17e6194dcb-image.png

            VinnyV Offline
            VinnyV Offline
            Vinny
            ModalAI Team
            wrote on last edited by Vinny
            #10

            Hi @labkit
            MCBL-00091-1 is by default meant for ESC tools...i.e.: it will plug into the ESC side of that cable you removed, not the VOXL 2 side:
            https://docs.modalai.com/cable-datasheets/#mcbl-00091
            To use it for HWIL, pins 2&3 need to be swapped as noted: https://docs.modalai.com/cable-userguides/#m0163-4-pin-jst-to-4-pin-jst-cross-over-example
            You do not need to have the M0163 if you are comfortable re-pinning JSTs:
            https://docs.modalai.com/cable-userguides/#flightcore-v2-conversion-cables-info

            5f5ba346-20e1-4428-8a0d-afbcd7f4187b-image.png
            Hope this helps.
            If you have already determined that and made the swap, then please ignore my message.
            Thanks!

            L 1 Reply Last reply
            0
            • VinnyV Vinny

              Hi @labkit
              MCBL-00091-1 is by default meant for ESC tools...i.e.: it will plug into the ESC side of that cable you removed, not the VOXL 2 side:
              https://docs.modalai.com/cable-datasheets/#mcbl-00091
              To use it for HWIL, pins 2&3 need to be swapped as noted: https://docs.modalai.com/cable-userguides/#m0163-4-pin-jst-to-4-pin-jst-cross-over-example
              You do not need to have the M0163 if you are comfortable re-pinning JSTs:
              https://docs.modalai.com/cable-userguides/#flightcore-v2-conversion-cables-info

              5f5ba346-20e1-4428-8a0d-afbcd7f4187b-image.png
              Hope this helps.
              If you have already determined that and made the swap, then please ignore my message.
              Thanks!

              L Offline
              L Offline
              labkit
              Contributor
              wrote on last edited by
              #11

              @Vinny I swapped pins 2&3 so that the former pin 2 is now pin 3 and vice versa. The swap occurred with no damage to the pins as far as I am aware, but the "Serial port closed" issue is still present. This image shows the correct rewiring, right? The RX and TX wires (white and green) are switched and the USB to JST is in J18 on the VOXL 2. The ESC is unplugged from VOXL 2.

              9232cc3f-40c4-4b01-9af2-7f714c5f9b26-image.png

              VinnyV 1 Reply Last reply
              0
              • L labkit

                @Vinny I swapped pins 2&3 so that the former pin 2 is now pin 3 and vice versa. The swap occurred with no damage to the pins as far as I am aware, but the "Serial port closed" issue is still present. This image shows the correct rewiring, right? The RX and TX wires (white and green) are switched and the USB to JST is in J18 on the VOXL 2. The ESC is unplugged from VOXL 2.

                9232cc3f-40c4-4b01-9af2-7f714c5f9b26-image.png

                VinnyV Offline
                VinnyV Offline
                Vinny
                ModalAI Team
                wrote on last edited by
                #12

                Hi @labkit
                Looks good! At least now the efforts with Eric and team are not in vain since that is the correct MCBL-00091 config for HWIL.
                You are in good hands with them now

                L 1 Reply Last reply
                0
                • VinnyV Vinny

                  Hi @labkit
                  Looks good! At least now the efforts with Eric and team are not in vain since that is the correct MCBL-00091 config for HWIL.
                  You are in good hands with them now

                  L Offline
                  L Offline
                  labkit
                  Contributor
                  wrote on last edited by
                  #13

                  @Eric-Katzfey I rewired the cable but the issue hasn't changed at all. It's still reporting "Serial port not found!" and the /dev/ttyUSB0 that you mentioned still isn't available from the Gazebo Docker command line.

                  Eric KatzfeyE 1 Reply Last reply
                  0
                  • L labkit

                    @Eric-Katzfey I rewired the cable but the issue hasn't changed at all. It's still reporting "Serial port not found!" and the /dev/ttyUSB0 that you mentioned still isn't available from the Gazebo Docker command line.

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

                    @labkit Is there another Linux computer that you can try? Many people use HITL and no one has reported any issues like this so I am suspecting that there is something about the environment on your machine that is causing the problem.

                    L 1 Reply Last reply
                    0
                    • L labkit

                      I got Docker to avoid the error by doing the steps in the tutorial in a different order with setup on the drone coming first. This must have been why I didn't receive the "serial port closed" error when I first tried to set up the simulation two days ago. However, I don't think the simulation is in shape to run yet, all I've managed is to get back to where I was originally....

                      L Offline
                      L Offline
                      labkit
                      Contributor
                      wrote on last edited by labkit
                      #15

                      Also, ignore my earlier post that said I had fixed things by performing the tutorial steps in a different order. I was mistaken in thinking I had resolved the original issue. The next message explained why I made that mistake.

                      1 Reply Last reply
                      0
                      • Eric KatzfeyE Eric Katzfey

                        @labkit Is there another Linux computer that you can try? Many people use HITL and no one has reported any issues like this so I am suspecting that there is something about the environment on your machine that is causing the problem.

                        L Offline
                        L Offline
                        labkit
                        Contributor
                        wrote on last edited by
                        #16

                        @Eric-Katzfey I will look into trying this.

                        L 1 Reply Last reply
                        0
                        • Alexander SaundersA Alexander Saunders referenced this topic on
                        • L labkit

                          @Eric-Katzfey I will look into trying this.

                          L Offline
                          L Offline
                          labkit
                          Contributor
                          wrote on last edited by
                          #17

                          @Eric-Katzfey Issue is mostly resolved. There were two main errors to fix. The first was that the cable that I was using needed to have its RX and TX wires swapped as Vinny pointed out. The second was that Docker Desktop needed to be uninstalled and replaced with only the core Docker CE Engine. After doing this, the HITL seems to be up and running on the alternate Linux computer I tested with. On the original computer, the "Serial port closed error" is no longer present although there does seem to be a graphics issue when attempting to run the Gazebo image with graphics.

                          8d0e6ab0-9969-4fb4-853c-4879b46992bf-image.png

                          Once this is fixed I think it should be all ready to perform simulations.

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