Gazebo hitl_iris example, Error Code 12 Msg: Unable to find uri[model://iris_hitl]

PX4 Autopilot Simulation 🌍
1

I’m trying to run the gazebo hitl example, using the steps provided at the following location:
(Hardware in the Loop Simulation (HITL) | PX4 Guide (main))

Steps that I executed:

(QGC not running)
(serialDevice is /dev/ttyACM0, so no change required to “Tools/simulation/gazebo/sitl_gazebo/models/iris_hitl/iris_hitl.sdf”)

In Ubuntu:
cd ~/PX4-Autopilot
DONT_RUN=1 make px4_sitl_default gazebo
source Tools/simulation/gazebo/setup_gazebo.bash $(pwd) $(pwd)/build/px4_sitl_default
gazebo Tools/simulation/gazebo/sitl_gazebo/worlds/hitl_iris.world

Result:
Gazebo started after a fairly long delay (~1 minute), but I got the following error message in Ubuntu (and no vehicle showing in gazebo):
Error Code 12 Msg: Unable to find uri[model://iris_hitl]

My setup:
Windows 11 Pro, OS Build 22000.1455
Ubuntu 20.04 (running under WSL 2)
serialDevice is /dev/ttyACM0
~/PX4-Autopilot “branch is up to date with ‘origin/main’”

2

Not sure what happened here. Let me tag @bperseghetti, maybe he knows.

3

I am now able to run the example. It required changing the permissions for /dev/ttyACM0 as follows:
sudo chmod 666 /dev/ttyACM0

The result that I reported originally apparently occurred when I attempted to run the example using sudo (as follows):
sudo gazebo Tools/simulation/gazebo/sitl_gazebo/worlds/hitl_iris.world

When I ran the example as a user, as follows (without using sudo):
gazebo Tools/simulation/gazebo/sitl_gazebo/worlds/hitl_iris.world

Gazebo started and displayed the IRIS vehicle, but I got the following output:
krr@ASEC_XPS_1:~/PX4-Autopilot$ gazebo Tools/simulation/gazebo/sitl_gazebo/worlds/hitl_iris.world
Warning [parser.cc:833] XML Attribute[version] in element[sdf] not defined in SDF, ignoring.
Warning [parser.cc:833] XML Attribute[version] in element[sdf] not defined in SDF, ignoring.
Error opening serial device: open: Permission denied
Serial port closed!
Serial port closed!
… (“Serial port closed!” repeated many times per second)

4

I believe the correct fix is to add your user to the dialout group: