VOXL FPV Racing 4-in-1 ESC with flight core v2 and voxl2

Eric Katzfey

@Jetson-Nano How are the VOXL_ESC parameters set on your FCv2? There could be a UART baud rate mismatch between what FCv2 is using and what the ESC is using.

Alex Kushleyev

@Jetson-Nano , if the voxl_esc driver is started by PX4 running on the Flight Core, it should print out debugging information to the UART console. The log below was taken from PX4 running on VOXL2 DSP, but the output should be the same when using Flight Core V2.

Please also note that the Flight Core (V2), when powered up, starts immediately (as opposed to VOXL2 booting takes a few seconds), so FC V2 will try to detect the ESC before the ESC exits bootloader (which takes 1 second after power is applied) and will fail to detect the ESC. This was fixed in our FC V2 drone config, please check your voxl-esc driver behavior. Here is the commit that added the delay of 1.5 seconds before starting voxl esc driver on FC V2:

(voxl-esc driver log from VOXL2 DSP is below)

INFO  [muorb] SLPI: VOXL_ESC: Starting VOXL ESC driver
INFO  [muorb] SLPI: VOXL_ESC: Opening UART ESC device 2, baud rate 2000000
INFO  [muorb] SLPI: VOXL_ESC: Successfully opened UART ESC device
INFO  [muorb] SLPI: VOXL_ESC: Detecting ESCs...
INFO  [muorb] SLPI: VOXL_ESC: 	ESC ID     : 0
INFO  [muorb] SLPI: VOXL_ESC: 	Board Type : 37: ModalAi 4-in-1 ESC (M0134-1)
INFO  [muorb] SLPI: VOXL_ESC: 	Unique ID  : 0x203330385246571900480024
INFO  [muorb] SLPI: VOXL_ESC: 	Firmware   : version   39, hash eb6fb500
INFO  [muorb] SLPI: VOXL_ESC: 	Bootloader : version  183, hash b4fa2cf8
INFO  [muorb] SLPI: VOXL_ESC: 	Reply time : 1646us
INFO  [muorb] SLPI: VOXL_ESC:
INFO  [muorb] SLPI: VOXL_ESC: 	ESC ID     : 1
INFO  [muorb] SLPI: VOXL_ESC: 	Board Type : 37: ModalAi 4-in-1 ESC (M0134-1)
INFO  [muorb] SLPI: VOXL_ESC: 	Unique ID  : 0x2033303852465719004D004D
INFO  [muorb] SLPI: VOXL_ESC: 	Firmware   : version   39, hash eb6fb500
INFO  [muorb] SLPI: VOXL_ESC: 	Bootloader : version  183, hash b4fa2cf8
INFO  [muorb] SLPI: VOXL_ESC: 	Reply time : 621us
INFO  [muorb] SLPI: VOXL_ESC:
INFO  [muorb] SLPI: VOXL_ESC: 	ESC ID     : 2
INFO  [muorb] SLPI: VOXL_ESC: 	Board Type : 37: ModalAi 4-in-1 ESC (M0134-1)
INFO  [muorb] SLPI: VOXL_ESC: 	Unique ID  : 0x203330385246571900500042
INFO  [muorb] SLPI: VOXL_ESC: 	Firmware   : version   39, hash eb6fb500
INFO  [muorb] SLPI: VOXL_ESC: 	Bootloader : versiINFO  [qshell] Send cmd: 'voxl_esc start'
INFO  [muorb] SLPI: VOXL_ESC: 	Reply time : 1120us
INFO  [muorb] SLPI: VOXL_ESC:
INFO  [muorb] SLPI: VOXL_ESC: 	ESC ID     : 3
INFO  [muorb] SLPI: VOXL_ESC: 	Board Type : 37: ModalAi 4-in-1 ESC (M0134-1)
INFO  [muorb] SLPI: VOXL_ESC: 	Unique ID  : 0x2033303852465719004D0050
INFO  [muorb] SLPI: VOXL_ESC: 	Firmware   : version   39, hash eb6fb500
INFO  [muorb] SLPI: VOXL_ESC: 	Bootloader : version  183, hash b4fa2cf8
INFO  [muorb] SLPI: VOXL_ESC: 	Reply time : 617us
INFO  [muorb] SLPI: VOXL_ESC:
INFO  [muorb] SLPI: VOXL_ESC: Use extened rpm packet : 1
INFO  [muorb] SLPI: VOXL_ESC: All ESCs successfully detected

Jetson Nano

@Alex-Kushleyev Thank you for reverting back. I will verify this and get back.

I changed the firmware version to the voxl-fpv-dev still the FC is not detecting the ESC.

if i start esc through voxl_esc start , it is starting

could please verify the parameters I mentioned.

nsh> voxl_esc status
INFO  [voxl_esc] Max update rate: 0 Hz
INFO  [voxl_esc] Outputs on: no
INFO  [voxl_esc] UART port: /dev/ttyS4
INFO  [voxl_esc] UART open: no
INFO  [voxl_esc] 
INFO  [voxl_esc] Params: VOXL_ESC_CONFIG: 1
INFO  [voxl_esc] Params: VOXL_ESC_MODE: 0
INFO  [voxl_esc] Params: VOXL_ESC_BAUD: 250000
INFO  [voxl_esc] Params: VOXL_ESC_FUNC1: 101
INFO  [voxl_esc] Params: VOXL_ESC_FUNC2: 104
INFO  [voxl_esc] Params: VOXL_ESC_FUNC3: 102
INFO  [voxl_esc] Params: VOXL_ESC_FUNC4: 103
INFO  [voxl_esc] Params: VOXL_ESC_SDIR1: 0
INFO  [voxl_esc] Params: VOXL_ESC_SDIR2: 0
INFO  [voxl_esc] Params: VOXL_ESC_SDIR3: 0
INFO  [voxl_esc] Params: VOXL_ESC_SDIR4: 0
INFO  [voxl_esc] Params: VOXL_ESC_RPM_MIN: 5500
INFO  [voxl_esc] Params: VOXL_ESC_RPM_MAX: 15000
INFO  [voxl_esc] Params: VOXL_ESC_T_PERC: 90
INFO  [voxl_esc] Params: VOXL_ESC_T_DEAD: 20
INFO  [voxl_esc] Params: VOXL_ESC_T_EXPO: 35
INFO  [voxl_esc] Params: VOXL_ESC_T_MINF: 0.150000
INFO  [voxl_esc] Params: VOXL_ESC_T_COSP: 0.990000
INFO  [voxl_esc] Params: VOXL_ESC_VLOG: 0
INFO  [voxl_esc] Params: VOXL_ESC_PUB_BST: 1
INFO  [voxl_esc] Params: VOXL_ESC_T_WARN: 0
INFO  [voxl_esc] Params: VOXL_ESC_T_OVER: 0
INFO  [voxl_esc] Params: GPIO_CTL_CH: 0
INFO  [voxl_esc] 
INFO  [voxl_esc] -- ID: 0
INFO  [voxl_esc]    Motor:           1
INFO  [voxl_esc]    Direction:       1
INFO  [voxl_esc]    State:           0
INFO  [voxl_esc]    Requested:       0 RPM
INFO  [voxl_esc]    Measured:        0 RPM
INFO  [voxl_esc]    Command Counter: 0
INFO  [voxl_esc]    Voltage:         0.000000 VDC
INFO  [voxl_esc] 
INFO  [voxl_esc] -- ID: 1
INFO  [voxl_esc]    Motor:           4
INFO  [voxl_esc]    Direction:       1
INFO  [voxl_esc]    State:           0
INFO  [voxl_esc]    Requested:       0 RPM
INFO  [voxl_esc]    Measured:        0 RPM
INFO  [voxl_esc]    Command Counter: 0
INFO  [voxl_esc]    Voltage:         0.000000 VDC
INFO  [voxl_esc] 
INFO  [voxl_esc] -- ID: 2
INFO  [voxl_esc]    Motor:           2
INFO  [voxl_esc]    Direction:       1
INFO  [voxl_esc]    State:           0
INFO  [voxl_esc]    Requested:       0 RPM
INFO  [voxl_esc]    Measured:        0 RPM
INFO  [voxl_esc]    Command Counter: 0
INFO  [voxl_esc]    Voltage:         0.000000 VDC
INFO  [voxl_esc] 
INFO  [voxl_esc] -- ID: 3
INFO  [voxl_esc]    Motor:           3
INFO  [voxl_esc]    Direction:       1
INFO  [voxl_esc]    State:           0
INFO  [voxl_esc]    Requested:       0 RPM
INFO  [voxl_esc]    Measured:        0 RPM
INFO  [voxl_esc]    Command Counter: 0
INFO  [voxl_esc]    Voltage:         0.000000 VDC
INFO  [voxl_esc] 
voxl_esc: cycle: 0 events, 0us elapsed, 0.00us avg, min 0us max 0us 0.000us rms
voxl_esc: output update interval: 0 events, 0.00us avg, min 0us max 0us 0.000us rms
INFO  [mixer_module] Param prefix: VOXL_ESC
control latency: 0 events, 0us elapsed, 0.00us avg, min 0us max 0us 0.000us rms
Channel Configuration:
Channel 0: func:   0, value: 0, failsafe: 0, disarmed: 0, min: 5500, max: 15000
Channel 1: func:   0, value: 0, failsafe: 0, disarmed: 0, min: 5500, max: 15000
Channel 2: func:   0, value: 0, failsafe: 0, disarmed: 0, min: 5500, max: 15000
Channel 3: func:   0, value: 0, failsafe: 0, disarmed: 0, min: 5500, max: 15000

Jetson Nano

@Eric-Katzfey @Alex-Kushleyev

Voxl2 is connected to Flight core v2 through telem 1.
ESC is connected to flight core through telem 2.
the parameters are the following

Screenshot from 2025-04-22 09-41-07.png

Screenshot from 2025-04-22 09-42-31.png

Screenshot from 2025-04-22 09-40-50.png

Alex Kushleyev

@Jetson-Nano said in VOXL FPV Racing 4-in-1 ESC with flight core v2 and voxl2:

if i start esc through voxl_esc start , it is starting

Can you please provide the debug prints that voxl_esc driver outputs when you call voxl_esc start ?

Alex

Jetson Nano

@Alex-Kushleyev When I run it for sometime it is makes the ESC blink once.
then once again if I run the command it gives the following statement
Error [voxl_esc] Task already running

Alex Kushleyev

@Jetson-Nano , you can stop the task and run it again or just look at the console output when you power on FC V2, so you see what happens when voxl_esc task prints when it start for the first time.

Jetson Nano

@Alex-Kushleyev

nsh> voxl_esc stop
ERROR [voxl_esc] timeout, forcing stop
ERROR [voxl_esc] failed restoring uart to original state
ERROR [voxl_esc] error closing uart
nsh> voxl_esc start
ERROR [px4_work_queue] wq:ttyS4 not available
ERROR [px4_work_queue] init failed
INFO  [voxl_esc] Starting VOXL ESC driver
INFO  [voxl_esc] Params: VOXL_ESC_CONFIG: 1
INFO  [voxl_esc] Params: VOXL_ESC_MODE: 0
INFO  [voxl_esc] Params: VOXL_ESC_BAUD: 250000
INFO  [voxl_esc] Params: VOXL_ESC_FUNC1: 101
INFO  [voxl_esc] Params: VOXL_ESC_FUNC2: 104
INFO  [voxl_esc] Params: VOXL_ESC_FUNC3: 102
INFO  [voxl_esc] Params: VOXL_ESC_FUNC4: 103
INFO  [voxl_esc] Params: VOXL_ESC_SDIR1: 0
INFO  [voxl_esc] Params: VOXL_ESC_SDIR2: 0
INFO  [voxl_esc] Params: VOXL_ESC_SDIR3: 0
INFO  [voxl_esc] Params: VOXL_ESC_SDIR4: 0
INFO  [voxl_esc] Params: VOXL_ESC_RPM_MIN: 5500
INFO  [voxl_esc] Params: VOXL_ESC_RPM_MAX: 15000
INFO  [voxl_esc] Params: VOXL_ESC_T_PERC: 90
INFO  [voxl_esc] Params: VOXL_ESC_T_DEAD: 20
INFO  [voxl_esc] Params: VOXL_ESC_T_EXPO: 35
INFO  [voxl_esc] Params: VOXL_ESC_T_MINF: 0.150000
INFO  [voxl_esc] Params: VOXL_ESC_T_COSP: 0.990000
INFO  [voxl_esc] Params: VOXL_ESC_VLOG: 0
INFO  [voxl_esc] Params: VOXL_ESC_PUB_BST: 1
INFO  [voxl_esc] Params: VOXL_ESC_T_WARN: 0
INFO  [voxl_esc] Params: VOXL_ESC_T_OVER: 0
INFO  [voxl_esc] Params: GPIO_CTL_CH: 0
nsh>

can you verify whether it is a parameter related error. I have mentioned the parameters in the above thread.

Alex Kushleyev

@Jetson-Nano said in VOXL FPV Racing 4-in-1 ESC with flight core v2 and voxl2:

ERROR [px4_work_queue] wq:ttyS4 not available

the error above seems like an issue.

Also is your ESC actually running at 250K baud rate? Did you verify this using voxl-esc tools?

Additionally, it seems the voxl_esc driver does not produce the prints I was expecting, let me check to make sure the FC V2 is using the latest voxl_esc implementation.

Alex

Jetson Nano

@Alex-Kushleyev
Yes it is running in the 250k baud rate.
I did not verify with the voxl-esc tools. I directly connected it to the FC.
I am using the voxl-fpv-dev version of px4

Alex Kushleyev

@Jetson-Nano , what do you mean voxl-fpv-dev version of px4? can you provide the link to the exact release?

Jetson Nano

@Alex-Kushleyev
https://github.com/modalai/px4-firmware/tree/voxl-fpv-dev

Jetson Nano

@Alex-Kushleyev here you had mentioned a version where the change has been made with respect to the delay.
https://forum.modalai.com/post/21951

Alex Kushleyev

@Jetson-Nano , from your above screen shot from QGC, it seems you are using TELEM2 for MAV0, so that is probably why the port is not able to open. You should probably set MAV_0_CONFIG to Disabled...

ERROR [px4_work_queue] wq:ttyS4 not available

Jetson Nano

@Alex-Kushleyev Thank you for the help . I changed the parameter and now the ESC has been initialised. motor are able to rotate.
Also is there any other parameter i should be aware of

Alex Kushleyev

@Jetson-Nano , since you are probably using a custom motor and propeller you should:

first of all, update the ESC firmware to the latest
calibrate the ESC for the motor/propeller and upload params
update min and max rpm params in PX4 because they are used to scale the control output
set the correct motor mapping and direction in px4 params
i also recommend updating the baud rate to at least 921600 (or 1M). We are using 2Mbit for all latest ESC configs now. This reduces latency and ensures that you don't have ESC packet drops (depending on the update rate of your flight control loop)

In order to perform the updates and tuning, you will need to use voxl-esc tools. Please see the following page for more info: https://docs.modalai.com/voxl-escs/faq/

Alex

Jetson Nano

@Alex-Kushleyev Thank you for the support. I will make the changes you have mentioned.