PX4 ULog

Log Simulink signals to an SD card in ULog format

Since R2023b

Add-On Required: This feature requires the UAV Toolbox Support Package for PX4 Autopilots add-on.

Libraries:
UAV Toolbox Support Package for PX4 Autopilots / PX4 Utility Blocks

Description

The PX4 ULog block logs the Simulink^® signals to an SD Card in the ULog format.

In PX4 Autopilots, the system architecture uses logger module that logs topics in ULog file formats. PX4 uses  ULog file format for uORB logging messages. These messages are commonly known as micro-ORB (Object Request Broker) and form the basis for subscribe, publish architecture in PX4.

The ULog format is efficient for post-flight analysis. Using ulogreader, flight logger app or online tools you can analyze, visualize, and convert ULog files to gain insights and improve the performance of PX4-based autonomous systems.

The number of ports in the block updates as per the uORB topic selected. To create your own topic, use createPX4uORBMessage API. The block is currently configured with default uORB topic SL_CustomPX4uORB that is build during setup screens.

Note

This block does not support PX4 Host target and Connected I/O Simulation.

Examples

Log Simulink Signals Using PX4 ULog

Log signals in ULog format from a Simulink® model running on a Pixhawk® hardware and retrieve the log files from the SD card for further analysis.

Open Model

Ports

Input

expand all

double_a — First input signal, specified as double
scalar

Input signal to be logged by the block, specified as double.

Data Types: double

double_b — Second input signal, specified as double
scalar

Input signal to be logged by the block, specified as double.

Data Types: double

single_a — First input signal, specified as single
scalar

Input signal to be logged by the block, specified as single.

Data Types: single

single_b — Second input signal, specified as single
scalar

Input signal to be logged by the block, specified as single.

Data Types: single

Parameters

expand all

Topic — Name of the uORB topic to which the Simulink signals are to be logged
SL_CustomPX4uORB (default) | one of the uORB topics

Select the name of the uORB topic that the block needs to log Simulink signals. Click Select to browse topic names available in the Firmware/msg folder of the px4 directory that you downloaded.