Negative time point in rclcpp::Time

[stergiosba]

Hey guys, great project thank you very much. I am facing the following issue sometimes where I get negative time and I was hoping you might have an idea why.

Appreciate any help.

After launching with:

ros2 launch mocap_optitrack mocap.launch.py config:=mocap_probe.yaml

I get the following error sporadically (about 6 times in an hour):

[INFO] [launch]: All log files can be found below /home/athena/.ros/log/2024-12-03-18-12-18-412721-Athena-6406
[INFO] [launch]: Default logging verbosity is set to INFO
[INFO] [launch.user]: Config path: /home/athena/Downloads/mocap_optitrack/install/mocap_optitrack/share/mocap_optitrack/config/mocap_probe.yaml
[INFO] [mocap_node-1]: process started with pid [6407]
[mocap_node-1] [WARN] [1733267538.442367401] [mocap_node]: Could not get server version, using auto
[mocap_node-1] [INFO] [1733267538.443137514] [mocap_node]: Creating socket...
[mocap_node-1] [INFO] [1733267538.443151154] [mocap_node]: Setting socket options...
[mocap_node-1] [INFO] [1733267538.443155504] [mocap_node]: Local address: 0.0.0.0:1511
[mocap_node-1] [INFO] [1733267538.443163621] [mocap_node]: Binding socket to local address...
[mocap_node-1] [INFO] [1733267538.443168193] [mocap_node]: Joining multicast group 239.255.42.99...
[mocap_node-1] [INFO] [1733267538.443177112] [mocap_node]: Enabling non-blocking I/O
[mocap_node-1] [WARN] [1733267539.443798329] [mocap_node]: Client has not received server info request. Parsing data message aborted.
[mocap_node-1] [WARN] [1733267539.444066737] [mocap_node]: Client has not received server info request. Parsing data message aborted.
[mocap_node-1] [WARN] [1733267539.444279789] [mocap_node]: Client has not received server info request. Parsing data message aborted.
[mocap_node-1] [WARN] [1733267539.444460162] [mocap_node]: Client has not received server info request. Parsing data message aborted.
[mocap_node-1] [WARN] [1733267540.445453675] [mocap_node]: Client has not received server info request. Parsing data message aborted.
[mocap_node-1] [INFO] [1733267540.445780131] [mocap_node]: NATNet Version : 4.1.0.0
[mocap_node-1] [INFO] [1733267540.445802976] [mocap_node]: Server Version : 3.1.1.1
[mocap_node-1] [INFO] [1733267540.459861089] [mocap_node]: Initialization complete
[mocap_node-1] terminate called after throwing an instance of 'std::runtime_error'
[mocap_node-1]   what():  cannot store a negative time point in rclcpp::Time

[whoenig]

That's very weird - I have never seen that. In the code we seem to just use the now function from the node. The best would be to attach a debugger and see what the values are (some hints on how to debug a ROS node are here: https://imrclab.github.io/crazyswarm2/howto.html#debugging).