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Configuring battery monitor with FPV ESC

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  • Alex KushleyevA Alex Kushleyev

    @restore , This should be the correct PX4 version (it has support for this feature)

    When you start PX4, are the blue LEDs on the ESC blinking? if not, then PX4 is not communicating with the ESC, you may need to double check the baud rate setting (baud rate in ESC params needs to match the VOXL_ESC_BAUD.

    Related question, is the actuator test in PX4 working?

    Alex

    Dan JenningsD Offline
    Dan JenningsD Offline
    Dan Jennings
    Contributor
    wrote on last edited by
    #9

    @Alex-Kushleyev
    Yes, ESC is working, we're able to calibrate ESCs using esc tools, spin up motors in QGC, and have flown several times. Just having to be very conservative without battery status.

    Alex KushleyevA 1 Reply Last reply
    0
    • Dan JenningsD Dan Jennings

      @Alex-Kushleyev
      Yes, ESC is working, we're able to calibrate ESCs using esc tools, spin up motors in QGC, and have flown several times. Just having to be very conservative without battery status.

      Alex KushleyevA Offline
      Alex KushleyevA Offline
      Alex Kushleyev
      ModalAI Team
      wrote on last edited by Alex Kushleyev
      #10

      @Dan-Jennings,

      We will figure it out 🙂 quick question - what baud rate are you using for the ESC and also esc firmware version / hash? I will test with exact version of esc firmware and px4.

      If your baud rate is 250k, please change it to a higher value, we typically use 2M. If baud rate is too low, may not be fast enough to send the extra packet with total current.

      Alex KushleyevA 1 Reply Last reply
      0
      • Alex KushleyevA Alex Kushleyev

        @Dan-Jennings,

        We will figure it out 🙂 quick question - what baud rate are you using for the ESC and also esc firmware version / hash? I will test with exact version of esc firmware and px4.

        If your baud rate is 250k, please change it to a higher value, we typically use 2M. If baud rate is too low, may not be fast enough to send the extra packet with total current.

        Alex KushleyevA Offline
        Alex KushleyevA Offline
        Alex Kushleyev
        ModalAI Team
        wrote on last edited by
        #11

        Another question - when you use voxl-esc tools and spin id 2, do you get a total current measurement printed in terminal along with regular esc feedback?

        Alex KushleyevA R 2 Replies Last reply
        0
        • Alex KushleyevA Alex Kushleyev

          Another question - when you use voxl-esc tools and spin id 2, do you get a total current measurement printed in terminal along with regular esc feedback?

          Alex KushleyevA Offline
          Alex KushleyevA Offline
          Alex Kushleyev
          ModalAI Team
          wrote on last edited by
          #12

          @Dan-Jennings , did you figure out this one?

          the way the battery publishing works on M0138 (FPV) ESC and M0129 (Mini) ESC is as follows:

          • one of the MCUs on the ESC is hooked up to the total current sensor. On M0138 it is ID2, on M0129 it is ID3
          • when flight controller requests feedback from the ESC (by setting appropriate bit in the commanded RPM or Power control packet), the ESC ID with the current measurement will send out its regular feedback packet and right after the special battery status packet
          • this battery status packet is received and parsed by PX4 and if the VOXL_ESC_PUB_BST px4 param is set to 1, the battery status is published, code here
          • this only happens if voxl_esc px4 driver is running and and it is communicating with the ESC (e.g. UART baud rate is correct). You will see the ESC flash all 4 blue leds, which means the commands (disarmed rpms = 0 if not in flight) are received from the PX4 flight controller
          • you can view the battery status message in VOXL2 terminal using the following command:
          px4-listener battery_status
          

          I hope this helps!

          Alex

          Dan JenningsD 1 Reply Last reply
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          • Alex KushleyevA Alex Kushleyev

            @Dan-Jennings , did you figure out this one?

            the way the battery publishing works on M0138 (FPV) ESC and M0129 (Mini) ESC is as follows:

            • one of the MCUs on the ESC is hooked up to the total current sensor. On M0138 it is ID2, on M0129 it is ID3
            • when flight controller requests feedback from the ESC (by setting appropriate bit in the commanded RPM or Power control packet), the ESC ID with the current measurement will send out its regular feedback packet and right after the special battery status packet
            • this battery status packet is received and parsed by PX4 and if the VOXL_ESC_PUB_BST px4 param is set to 1, the battery status is published, code here
            • this only happens if voxl_esc px4 driver is running and and it is communicating with the ESC (e.g. UART baud rate is correct). You will see the ESC flash all 4 blue leds, which means the commands (disarmed rpms = 0 if not in flight) are received from the PX4 flight controller
            • you can view the battery status message in VOXL2 terminal using the following command:
            px4-listener battery_status
            

            I hope this helps!

            Alex

            Dan JenningsD Offline
            Dan JenningsD Offline
            Dan Jennings
            Contributor
            wrote on last edited by
            #13

            @Alex-Kushleyev still pending on this. Have had other issues to solve. Will be starting another thread shortly.

            1 Reply Last reply
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            • R restore referenced this topic on
            • Alex KushleyevA Alex Kushleyev

              Another question - when you use voxl-esc tools and spin id 2, do you get a total current measurement printed in terminal along with regular esc feedback?

              R Offline
              R Offline
              restore
              Regular
              wrote on last edited by
              #14

              @Alex-Kushleyev

              We're finally rebuilt and recalibrated, but still no battery status. All 4 blue LEDs are flashing on the ESC, so the voxl_esc px4 driver should be running but we get:

              voxl2:/$ px4-listener battery_status
              never published
              

              Where would that PX4 param be located?

              Alex KushleyevA 1 Reply Last reply
              0
              • R restore

                @Alex-Kushleyev

                We're finally rebuilt and recalibrated, but still no battery status. All 4 blue LEDs are flashing on the ESC, so the voxl_esc px4 driver should be running but we get:

                voxl2:/$ px4-listener battery_status
                never published
                

                Where would that PX4 param be located?

                Alex KushleyevA Offline
                Alex KushleyevA Offline
                Alex Kushleyev
                ModalAI Team
                wrote on last edited by
                #15

                @restore , can you please check which version of voxl-px4 you are using? You can use “voxl-version” tool.

                R 1 Reply Last reply
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                • Alex KushleyevA Alex Kushleyev

                  @restore , can you please check which version of voxl-px4 you are using? You can use “voxl-version” tool.

                  R Offline
                  R Offline
                  restore
                  Regular
                  wrote on last edited by
                  #16

                  @Alex-Kushleyev
                  We are using px4 version 1.14.0-2.0.68
                  I connected to px4 with QGC and was able to confirm that VOXL_ESC_PUB_BST is enabled. It'd still be handy to know where those params are stored so we can edit them while connected through adb.

                  Thanks

                  tomT 1 Reply Last reply
                  0
                  • R restore

                    @Alex-Kushleyev
                    We are using px4 version 1.14.0-2.0.68
                    I connected to px4 with QGC and was able to confirm that VOXL_ESC_PUB_BST is enabled. It'd still be handy to know where those params are stored so we can edit them while connected through adb.

                    Thanks

                    tomT Offline
                    tomT Offline
                    tom
                    admin
                    wrote on last edited by
                    #17

                    @restore The px4 parameters are stored in a binary file at /data/px4/param/parameters so you can't modify that file directly.

                    However you can use the following to set a param:

                    px4-param set PARAM_NAME PARAM_VALUE
                    

                    or view parameters with

                    px4-param show
                    
                    Alex KushleyevA 1 Reply Last reply
                    0
                    • tomT tom

                      @restore The px4 parameters are stored in a binary file at /data/px4/param/parameters so you can't modify that file directly.

                      However you can use the following to set a param:

                      px4-param set PARAM_NAME PARAM_VALUE
                      

                      or view parameters with

                      px4-param show
                      
                      Alex KushleyevA Offline
                      Alex KushleyevA Offline
                      Alex Kushleyev
                      ModalAI Team
                      wrote on last edited by
                      #18

                      @restore, also can you please check which version of ESC firmware you are running on the FPV ESC? you can do this using voxl-esc tools (while px4 is not running). voxl-esc scan

                      I suggest to update to the latest ESC firmware in voxl-esc repository (dev branch).

                      R 1 Reply Last reply
                      0
                      • Alex KushleyevA Alex Kushleyev

                        @restore, also can you please check which version of ESC firmware you are running on the FPV ESC? you can do this using voxl-esc tools (while px4 is not running). voxl-esc scan

                        I suggest to update to the latest ESC firmware in voxl-esc repository (dev branch).

                        R Offline
                        R Offline
                        restore
                        Regular
                        wrote on last edited by
                        #19

                        @Alex-Kushleyev
                        ESCs are firmware version 39, hash 17d64675
                        I checked /usr/share/modalai/voxl-esc-tools/firmware and the M0138 firmware matches the one here.

                        modalai_esc_firmware_m0138_1_v0_39_RC11_17d64675.bin
                        
                        Alex KushleyevA 1 Reply Last reply
                        0
                        • R restore

                          @Alex-Kushleyev
                          ESCs are firmware version 39, hash 17d64675
                          I checked /usr/share/modalai/voxl-esc-tools/firmware and the M0138 firmware matches the one here.

                          modalai_esc_firmware_m0138_1_v0_39_RC11_17d64675.bin
                          
                          Alex KushleyevA Offline
                          Alex KushleyevA Offline
                          Alex Kushleyev
                          ModalAI Team
                          wrote on last edited by Alex Kushleyev
                          #20

                          @restore, thank you for checking.

                          Let's do another test:

                          • for safety, remove propellers from motors
                          • with px4 disabled, go to /usr/share/modalai/voxl-esc-tools on voxl2
                          • run: ./voxl-esc-spin.py --id 2 --power 0 -- this will send a zero power command to ESC ID 2 (which measures the total current and sends back the battery status message). Motors will not spin. This will also request the battery status and you should see output (if possible you can use the latest voxl-esc tools from dev branch from (https://gitlab.com/voxl-public/voxl-sdk/utilities/voxl-esc/-/tree/dev) since I am not sure which voxl-esc version is installed on your board).
                          ./voxl-esc-spin.py --id 2 --power 0
                          ...
                          Found voxl-esc tools bin version: 1.6
                          VOXL Platform: M0054
                          Detected RB5 Flight, VOXL2 M0054 or M0104!
                          ...
                          ...
                          	Board      : version 42: ModalAi 4-in-1 ESC (M0138-1)
                          ...
                          ...
                          [0.017] (2) RPM: 0, PWR: 0, VOLTAGE: 15.612V, TEMPERATURE: 35.87C, CURRENT: 0.000A, BOARD_VOLTAGE: 15.612V, BOARD_CURRENT: -0.232A
                          [0.034] (2) RPM: 0, PWR: 0, VOLTAGE: 15.609V, TEMPERATURE: 35.88C, CURRENT: 0.000A, BOARD_VOLTAGE: 15.609V, BOARD_CURRENT: -0.200A
                          [0.060] (2) RPM: 0, PWR: 0, VOLTAGE: 15.610V, TEMPERATURE: 35.86C, CURRENT: 0.000A, BOARD_VOLTAGE: 15.610V, BOARD_CURRENT: -0.248A
                          [0.080] (2) RPM: 0, PWR: 0, VOLTAGE: 15.618V, TEMPERATURE: 35.85C, CURRENT: 0.000A, BOARD_VOLTAGE: 15.618V, BOARD_CURRENT: -0.224A
                          [0.095] (2) RPM: 0, PWR: 0, VOLTAGE: 15.612V, TEMPERATURE: 35.87C, CURRENT: 0.000A, BOARD_VOLTAGE: 15.612V, BOARD_CURRENT: -0.272A
                          [0.120] (2) RPM: 0, PWR: 0, VOLTAGE: 15.608V, TEMPERATURE: 35.90C, CURRENT: 0.000A, BOARD_VOLTAGE: 15.608V, BOARD_CURRENT: -0.240A
                          [0.134] (2) RPM: 0, PWR: 0, VOLTAGE: 15.612V, TEMPERATURE: 35.92C, CURRENT: 0.000A, BOARD_VOLTAGE: 15.612V, BOARD_CURRENT: -0.264A
                          [0.160] (2) RPM: 0, PWR: 0, VOLTAGE: 15.613V, TEMPERATURE: 35.90C, CURRENT: 0.000A, BOARD_VOLTAGE: 15.613V, BOARD_CURRENT: -0.248A
                          [0.174] (2) RPM: 0, PWR: 0, VOLTAGE: 15.608V, TEMPERATURE: 35.92C, CURRENT: 0.000A, BOARD_VOLTAGE: 15.608V, BOARD_CURRENT: -0.168A
                          

                          note that there are BOARD_VOLTAGE and BOARD_CURRENT printed, which are parsed from the battery status message coming from the ESC ID2. Please note that the current around 0 is not very accurate due to a very large measurement range (showing -0.2A, but the discharge current should really be positive based on our convention).

                          Alex

                          R 1 Reply Last reply
                          0
                          • Alex KushleyevA Alex Kushleyev

                            @restore, thank you for checking.

                            Let's do another test:

                            • for safety, remove propellers from motors
                            • with px4 disabled, go to /usr/share/modalai/voxl-esc-tools on voxl2
                            • run: ./voxl-esc-spin.py --id 2 --power 0 -- this will send a zero power command to ESC ID 2 (which measures the total current and sends back the battery status message). Motors will not spin. This will also request the battery status and you should see output (if possible you can use the latest voxl-esc tools from dev branch from (https://gitlab.com/voxl-public/voxl-sdk/utilities/voxl-esc/-/tree/dev) since I am not sure which voxl-esc version is installed on your board).
                            ./voxl-esc-spin.py --id 2 --power 0
                            ...
                            Found voxl-esc tools bin version: 1.6
                            VOXL Platform: M0054
                            Detected RB5 Flight, VOXL2 M0054 or M0104!
                            ...
                            ...
                            	Board      : version 42: ModalAi 4-in-1 ESC (M0138-1)
                            ...
                            ...
                            [0.017] (2) RPM: 0, PWR: 0, VOLTAGE: 15.612V, TEMPERATURE: 35.87C, CURRENT: 0.000A, BOARD_VOLTAGE: 15.612V, BOARD_CURRENT: -0.232A
                            [0.034] (2) RPM: 0, PWR: 0, VOLTAGE: 15.609V, TEMPERATURE: 35.88C, CURRENT: 0.000A, BOARD_VOLTAGE: 15.609V, BOARD_CURRENT: -0.200A
                            [0.060] (2) RPM: 0, PWR: 0, VOLTAGE: 15.610V, TEMPERATURE: 35.86C, CURRENT: 0.000A, BOARD_VOLTAGE: 15.610V, BOARD_CURRENT: -0.248A
                            [0.080] (2) RPM: 0, PWR: 0, VOLTAGE: 15.618V, TEMPERATURE: 35.85C, CURRENT: 0.000A, BOARD_VOLTAGE: 15.618V, BOARD_CURRENT: -0.224A
                            [0.095] (2) RPM: 0, PWR: 0, VOLTAGE: 15.612V, TEMPERATURE: 35.87C, CURRENT: 0.000A, BOARD_VOLTAGE: 15.612V, BOARD_CURRENT: -0.272A
                            [0.120] (2) RPM: 0, PWR: 0, VOLTAGE: 15.608V, TEMPERATURE: 35.90C, CURRENT: 0.000A, BOARD_VOLTAGE: 15.608V, BOARD_CURRENT: -0.240A
                            [0.134] (2) RPM: 0, PWR: 0, VOLTAGE: 15.612V, TEMPERATURE: 35.92C, CURRENT: 0.000A, BOARD_VOLTAGE: 15.612V, BOARD_CURRENT: -0.264A
                            [0.160] (2) RPM: 0, PWR: 0, VOLTAGE: 15.613V, TEMPERATURE: 35.90C, CURRENT: 0.000A, BOARD_VOLTAGE: 15.613V, BOARD_CURRENT: -0.248A
                            [0.174] (2) RPM: 0, PWR: 0, VOLTAGE: 15.608V, TEMPERATURE: 35.92C, CURRENT: 0.000A, BOARD_VOLTAGE: 15.608V, BOARD_CURRENT: -0.168A
                            

                            note that there are BOARD_VOLTAGE and BOARD_CURRENT printed, which are parsed from the battery status message coming from the ESC ID2. Please note that the current around 0 is not very accurate due to a very large measurement range (showing -0.2A, but the discharge current should really be positive based on our convention).

                            Alex

                            R Offline
                            R Offline
                            restore
                            Regular
                            wrote on last edited by
                            #21

                            @Alex-Kushleyev
                            Thanks for the help, as I was calibrating the ESCs I did notice those messages, which confused me as to why we weren't able to get that information in PX4. On Monday it suddenly just started working despite my changing nothing. Gotta love when things fix themselves

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