Using VOXL ESCs with PX4
Table of contents
Overview
The VOXL Flight and Flight Core systems provides the ability to easily and quickly interface with UART ESCs. The following guide provides you the necessary details on doing so.
Requirements
NOTE! This feature is currently in developer preview and requires you to load the PX4 FW from a branch
- VOXL Flight or Flight Core with this branch
- Note: this is scheduled to release with PX4 v1.12
- A ModalAI UART ESC:
- UART ESC Serial Cable MCBL-00013-1
Video Tutorial
For those of you who prefer videos, we have a video tutorial here that covers the software configuration and usage. Note, you’ll want to look at the hardware connections below as that part is skipped in this video.
TL;DR
Hardware Connections
Depending on the ESC version, follow the guide here:
PX4 Setup
Enable UART ESC
To enable the UART ESC feature, set the UART_ESC_CONFIG parameter to a value of 1 and power cycle the vehicle.
You can use QGroundControl’s Parameter feature to query and modify the UART_ESC params.
The remainder of the settings can be left as default if you followed the hardware connections described in the previous section.
TELEM3
The UART ESC uses /dev/ttyS1, same as TELEM3. On bootup, if any MAVLink instance is configured to use TELEM3, it will be disabled via boards/modalai/fc-v1/init/rc.board_defaults.
PX4 Params
The following are the PX4 parameters that are used by the modalai_esc driver:
| Name | Description | Min > Max (Incr.) | Default | Units |
|---|---|---|---|---|
UART_ESC_BAUD |
Baud rate between FlightController and ESC | (1) | 250000 | Bits/sec |
UART_ESC_CONFIG |
UART ESC Configuration Values: - 0: Disabled - 1: ModalAI ESC Reboot Required |
0 (Disabled) | ||
UART_ESC_MOTOR1 |
ESC CH0 (Motor 1) mapping to PX4 motor index. Negative value reverses spin. | -4 > 4 (1) |
3 | |
UART_ESC_MOTOR2 |
ESC CH1 (Motor 2) mapping to PX4 motor index. Negative value reverses spin. | -4 > 4 (1) |
2 | |
UART_ESC_MOTOR3 |
ESC CH2 (Motor 3) mapping to PX4 motor index. Negative value reverses spin. | -4 > 4 (1) |
4 | |
UART_ESC_MOTOR4 |
ESC CH3 (Motor 4) mapping to PX4 motor index. Negative value reverses spin. | -4 > 4 (1) |
1 | |
UART_ESC_RPM_MAX |
Maximum RPM, used by actuator output to determine thrust fullscale. | (1) | 15000 | RPM |
UART_ESC_RPM_MIN |
Minimum RPM, used by actuator output to determine thrust fullscale. | (1) | 5500 | RPM |
RGB LED Codes
This is currently a work in progress. The standard LED codes should output to the all the LED channels in a similar way as other PX4 RGB LED peripherals with the exception that the breathing pattern is replaced by a fast blink.