1 Overview

CI status	Debian package

Multi-drone PX4 SITL setup using Gazebo and ROS2. Generally follows https://docs.px4.io/main/en/sim_gazebo_gz/, but uses custom bringup scripts which serve as a showcase of https://github.com/asherikov/cdinit.

Workspace documentation is at http://www.sherikov.net/px4ws/.

1.1 Packages

PX4-Autopilot/PX4-Autopilot                         main             https://github.com/asherikov/PX4-Autopilot.git
cdinit                                              master           https://github.com/asherikov/cdinit.git
dds_agent/Micro-XRCE-DDS-Agent/Micro-XRCE-DDS-Agent v2.4.3           https://github.com/eProsima/Micro-XRCE-DDS-Agent.git
dds_agent/spdlog                                    v1.9.2           https://github.com/gabime/spdlog.git
px4_msgs                                            as_disable_tests https://github.com/asherikov/px4_msgs.git

PX4-Autopilot and Micro-XRCE-DDS-Agent are build using proxy packages in order to apply a few cmake tweaks

2 Usage

2.1 Building

Build px4sitl master package. Workspace is designed to be used with https://github.com/asherikov/ccws, but basic colcon build should work too.
Dependencies can be installed with rosdep except a few PX4 python dependencies that are installed with cmake during build step.

2.2 Binary package

Go to cloudsmith package repo, add new apt source, and run apt update.
sudo apt install px4ws--reldebug--all
source /opt/px4ws/px4ws__reldebug__all/setup.bash
Launch as explained below.

2.3 Running

Run px4sitl.sh -w walls -d 4001 "0,1.0,0,0,0,0" -d 4004 "0,-5.0,0,0,0,0" where -w specifies world (‘default’ if not set), -d specifies a drone model id and its location (x,y,z,r,p,y). Numerical ids can be found in a table at https://docs.px4.io/main/en/sim_gazebo_gz/.
px4sitl.sh also supports headless mode, which is enabled by passing -H flag.
Terminate by closing Gazebo gui, or with cdinit.sh shutdown.

2.4 cdinit services

All components are started using dinit service files located in px4sitl/cdinit_services/, see https://github.com/davmac314/dinit, https://github.com/asherikov/cdinit provides a cmake wrapper for dinit and helper scripts. Shell scripts are primarily used to setup environment and working directories.

2.4.1 Example

Start px4sitl.sh -w walls -d 4001 "0,1.0,0,0,0,0" -d 4004 "0,-5.0,0,0,0,0"
List services cdinit.sh list | sort to get something like

# dummy "boot" service
[[+]     ] cdinit_main
# Gazebo gui
[[+]     ] px4sitl_gz_gui (pid: XXX)
# PX4 instances, number after @ symbol is a corresponding system id
[[+]     ] px4sitl_px4@0 (pid: XXX)
[[+]     ] px4sitl_px4@1 (pid: XXX)
# logging services, cdinit_log helper adds timestamps
[{+}     ] cdinit_log@px4sitl_dds_agent (pid: XXX)
[{+}     ] cdinit_log@px4sitl_gz_clock (pid: XXX)
[{+}     ] cdinit_log@px4sitl_gz_gui (pid: XXX)
[{+}     ] cdinit_log@px4sitl_gz_headless (pid: XXX)
[{+}     ] cdinit_log@px4sitl_gz_wait (pid: XXX)
[{+}     ] cdinit_log@px4sitl_px4@0 (pid: XXX)
[{+}     ] cdinit_log@px4sitl_px4@1 (pid: XXX)
# Micro-XRCE-DDS-Agent bridging PX4 and ros2
[{+}     ] px4sitl_dds_agent (pid: XXX)
# Gazebo -> ROS2 simulation clock bridge
[{+}     ] px4sitl_gz_clock (pid: XXX)
# Gazebo simulation core
[{+}     ] px4sitl_gz_headless (pid: XXX)
# Helper service which waits for Gazebo to start
[{+}     ] px4sitl_gz_wait
# Dummy "master" service
[{+}     ] px4sitl_ros

Location of the log files depends on environment variables, e.g., ROS_LOG_DIR and is printed on startup.
Terminate using cdinit.sh shutdown. Since all processes are required, termination can also be performed by stopping a particular service, e.g., cdinit.sh stop --force px4sitl_gz_clock.

3 Troubleshooting

protobuf errors like the following could be caused by multiple Gazebo versions installed in parallel: [libprotobuf ERROR google/protobuf/descriptor_database.cc:121] File already exists in database: gz/msgs/pointcloud.proto

4 TODO

FindOpticalFlow.cmake is installed in a wrong place.
Is installation of px4/build/ intentional?
CMakeLists.txt, package.xml should not be installed.
Is spdlog needed?

5 Packages

5.1 Dependency graph

5.2 Doxygen documentation

Package	Dependencies	Dependents
cdinit	graph	graph
cdinit_examples	graph	graph
cdinit_manager	graph	graph
dds_agent	graph	graph
px4_msgs	graph	graph
px4sitl	graph	graph
spdlog	graph	graph

Total number of packages: 7

5.3 Workspace status

tags/0.1.2-0-g3a947a9
WSH: >>> status: git sources ---
Flags: H - version hash mismatch, M - uncommited changes
name                                                version          actual version                    HM repository
----                                                -------          --------------                    -- ----------
PX4-Autopilot/PX4-Autopilot                         main             heads/main-0-g2e586c4                https://github.com/asherikov/PX4-Autopilot.git
cdinit                                              master           heads/master-0-g3bb0858              https://github.com/asherikov/cdinit.git
dds_agent/Micro-XRCE-DDS-Agent/Micro-XRCE-DDS-Agent v2.4.3           tags/v2.4.3-0-g7362281               https://github.com/eProsima/Micro-XRCE-DDS-Agent.git
dds_agent/spdlog                                    v1.9.2           tags/v1.9.2-0-geb32206               https://github.com/gabime/spdlog.git
px4_msgs                                            as_disable_tests heads/as_disable_tests-0-g1398c8b    https://github.com/asherikov/px4_msgs.git

WSH:  <<< status: git sources ---

px4ws