PX4 Gazebo startup error on first execution due to gz_bridge timeout

[zahrakhan010]

When executing the following command in the terminal:

PX4_SYS_AUTOSTART=4002 PX4_GZ_MODEL_POSE="268.08,-128.22,3.86,0.00,0,-0.7" PX4_GZ_MODEL=x500_depth ./build/px4_sitl_default/bin/px4

The system throws an error with the following output:

INFO [init] starting gazebo with world: /home/coe/PX4-Autopilot/Tools/simulation/gz/worlds/default.sdf
INFO [gz_bridge] world: default, model name: x500_depth_0, simulation model: x500_depth
ERROR [gz_bridge] Service call timed out. Check GZ_SIM_RESOURCE_PATH is set correctly.
ERROR [gz_bridge] Task start failed (-1)
ERROR [init] gz_bridge failed to start and spawn model
ERROR [px4] Startup script returned with return value: 256

The world file is located in ~/PX4-Autopilot/Tools/simulation/gz/worlds, and I have set the environment variable GZ_SIM_RESOURCE_PATH in my .bashrc:

export GZ_SIM_RESOURCE_PATH=~/.gz/models

Gazebo opens with the warehouse world, but the drone does not spawn until I re-run the command. The error seems to occur only during the first execution. Any suggestions or ideas on what might be causing this issue?

[monemati]

@zahrakhan010 Maybe it's because of connection issue to Ignition server, you can try to turn off the firewall and try again:
sudo ufw disable

[zahrakhan010]

thank you for giving me suggestions, resolve the above bug, but now again im facing few issues, in terminal 2 run this command PX4_SYS_AUTOSTART=4002 PX4_GZ_MODEL_POSE="283.08,-136.22,3.86,0.00,0,-0.7" PX4_GZ_MODEL=x500_depth ./build/px4_sitl_default/bin/px4
and gave errors : " _____ __ __ ___
| ___ \ \ \ / / / |
| |/ / \ V / / /| |
| __/ / \ / /| |
| | / /^\ \ ___ |
_| / / |_/

px4 starting.

INFO [px4] startup script: /bin/sh etc/init.d-posix/rcS 0
env SYS_AUTOSTART: 4002
INFO [param] selected parameter default file parameters.bson
INFO [param] importing from 'parameters.bson'
INFO [parameters] BSON document size 442 bytes, decoded 442 bytes (INT32:16, FLOAT:6)
INFO [param] selected parameter backup file parameters_backup.bson
INFO [dataman] data manager file './dataman' size is 7872608 bytes
INFO [init] Gazebo simulator
INFO [init] starting gazebo with world: /home/coe/PX4-Autopilot/Tools/simulation/gz/worlds/default.sdf
INFO [init] PX4_GZ_MODEL_POSE set, spawning at: 0,0,1,0,0,0
INFO [gz_bridge] world: default, model name: x500_depth_0, simulation model: x500_depth
INFO [gz_bridge] Requested Model Position: 0,0,1,0,0,0
Warning: Ignoring XDG_SESSION_TYPE=wayland on Gnome. Use QT_QPA_PLATFORM=wayland to run on Wayland anyway.
ERROR [gz_bridge] Service call timed out. Check GZ_SIM_RESOURCE_PATH is set correctly.
WARN [gz_bridge] Service call timed out as Gazebo has not been detected.
INFO [lockstep_scheduler] setting initial absolute time to 104000 us
INFO [commander] LED: open /dev/led0 failed (22)
INFO [uxrce_dds_client] init UDP agent IP:127.0.0.1, port:8888
INFO [mavlink] mode: Normal, data rate: 4000000 B/s on udp port 18570 remote port 14550
INFO [tone_alarm] home set
INFO [mavlink] mode: Onboard, data rate: 4000000 B/s on udp port 14580 remote port 14540
INFO [mavlink] mode: Onboard, data rate: 4000 B/s on udp port 14280 remote port 14030
INFO [mavlink] mode: Gimbal, data rate: 400000 B/s on udp port 13030 remote port 13280
INFO [logger] logger started (mode=all)
INFO [logger] Start file log (type: full)
INFO [logger] [logger] ./log/2025-01-14/06_16_37.ulg
INFO [logger] Opened full log file: ./log/2025-01-14/06_16_37.ulg
INFO [mavlink] MAVLink only on localhost (set param MAV_{i}BROADCAST = 1 to enable network)
INFO [mavlink] MAVLink only on localhost (set param MAV{i}_BROADCAST = 1 to enable network)
INFO [px4] Startup script returned successfully
pxh> WARN [health_and_arming_checks] Preflight Fail: No connection to the ground control station
INFO [tone_alarm] notify positive
WARN [health_and_arming_checks] Preflight Fail: No connection to the ground control station
INFO [uxrce_dds_client] synchronized with time offset 1736835416087409us
WARN [health_and_arming_checks] Preflight Fail: No connection to the ground control station
INFO [uxrce_dds_client] successfully created rt/fmu/out/battery_status data writer, topic id: 19
INFO [uxrce_dds_client] successfully created rt/fmu/out/estimator_status_flags data writer, topic id: 82
INFO [uxrce_dds_client] successfully created rt/fmu/out/failsafe_flags data writer, topic id: 88
INFO [uxrce_dds_client] successfully created rt/fmu/out/manual_control_setpoint data writer, topic id: 137
INFO [uxrce_dds_client] successfully created rt/fmu/out/position_setpoint_triplet data writer, topic id: 181INFO [uxrce_dds_client] successfully created rt/fmu/out/sensor_combined data writer, topic id: 213
INFO [uxrce_dds_client] successfully created rt/fmu/out/timesync_status data writer, topic id: 236
INFO [uxrce_dds_client] successfully created rt/fmu/out/vehicle_land_detected data writer, topic id: 265
INFO [uxrce_dds_client] successfully created rt/fmu/out/vehicle_attitude data writer, topic id: 252
INFO [uxrce_dds_client] successfully created rt/fmu/out/vehicle_control_mode data writer, topic id: 259
INFO [uxrce_dds_client] successfully created rt/fmu/out/vehicle_global_position data writer, topic id: 260
INFO [uxrce_dds_client] successfully created rt/fmu/out/vehicle_gps_position data writer, topic id: 262
INFO [uxrce_dds_client] successfully created rt/fmu/out/vehicle_local_position data writer, topic id: 266
INFO [uxrce_dds_client] successfully created rt/fmu/out/vehicle_odometry data writer, topic id: 271
INFO [uxrce_dds_client] successfully created rt/fmu/out/vehicle_status data writer, topic id: 276
INFO [uxrce_dds_client] time sync converged
WARN [timesync] time jump detected. Resetting time synchroniser.
WARN [uxrce_dds_client] time sync no longer converged
INFO [uxrce_dds_client] time sync converged
WARN [timesync] time jump detected. Resetting time synchroniser.
WARN [uxrce_dds_client] time sync no longer converged
INFO [uxrce_dds_client] time sync converged

PX4 Exiting...
pxh> Exiting NOW.
" and in Terminal 5, I ran the command:

ros2 run px4_ros_com offboard_control

The output from Terminal 5 was:

coe@coe-System-Product-Name:~/ws_offboard_control$ ros2 run px4_ros_com offboard_control
Starting offboard control node...
[INFO] [1736834613.853484796] [offboard_control]: Arm command send

Although the arm command was successfully sent, the drone does not fly. Please help me resolve these issues and debug the problem.

[monemati]

@zahrakhan010 At first try PX4_GZ_STANDALONE=0 parameter like below:
PX4_SYS_AUTOSTART=4002 PX4_GZ_MODEL_POSE="283.08,-136.22,3.86,0.00,0,-0.7" PX4_GZ_STANDALONE=0 PX4_GZ_MODEL=x500_depth ./build/px4_sitl_default/bin/px4
If it did not fixed the issue then there is possible problem about time sync of xrce which you can follow this link. It's basically saying that you need to turn off UXRCE_DDS_SYNCT.

[zahrakhan010]

Since i'm new to ROS2, and i'm having difficulty figuring out how to bridge the LiDAR data to ROS2.

[monemati]

@zahrakhan010 I have not done that myself, but I think for lidar you should use a version of x500 drone which has lidar on it, and if there is a need for bridging, you can use ros_gz_bridge, something like below command (change lidar topic name, and type of message to pointcloud2 if needed):
ros2 run ros_gz_bridge parameter_bridge /lidar_scan@sensor_msgs/msg/LaserScan[sensor_msgs/LaserScan

[zahrakhan010]

Thank you so much for your help in resolving the previous issues I was facing. I really appreciate it!

Now, I have two concerns:

1. QGroundControl is unable to read distance sensor data. I have set up the LiDAR sensor in Gazebo simulation, but the distance data is not being displayed in QGroundControl, however /lidar_scan topic successfully displayed sensor data. How can I resolve this issue?
   

2. Issue with ros2 topic echo. When I run ros2 topic list, it shows many topics. However, when I try to echo a topic using:
   

ros2 topic echo /fmu/in/vehicle_visual_odometry

I get the following error:

The message type 'px4_msgs/msg/VehicleOdometry' is invalid.

How can I fix this issue?

Could you please help me resolve these problems?