Collision Monitor in Nav2 Not Displaying Polygons Correctly or Following Robot about navigation2 HOT 4 CLOSED

The polygons are all published on the process rate:

I just tested and see no issues, I would again however point to making sure that your cmd_vel is actually configured to get to the collision monitor since you mentioned changing some of those settings. Process is only called on the cmd_vel trigger which would explain all of this behavior, since we also publish the polygon at the start with activate, but just a single time.

So you'd see only the single polygon from the initial state and not updated. It gets updated by a re-subscribe since its in the base_footprint frame, so when it gets the new data, rviz automatically converts it into your visualizer's fixed frame.

If you echo and it appears once and not a live stream, it means the collision monitor itself is not receiving command velocity data and you should review the configuration guide or main examples for setting up the collision monitor: https://docs.nav2.org/configuration/packages/configuring-collision-monitor.html

I did mention that above in:

Your remark below would make me want to ensure that you have properly remapped that topic for the the collision monitor as well, since obviously the collision monitor needs to obtain the cmd-vel to do useful work.

Please review that.

from navigation2.

It looks like your QoS settings are wrong on that display?

Is it working properly minus the visualization? Just making sure I shouldn't scrutinize the code or your configuration for possible issues and its just a transport on the visualizations. Your remark below would make me want to ensure that you have properly remapped that topic for the the collision monitor as well, since obviously the collision monitor needs to obtain the cmd-vel to do useful work.

Change the remapping topics of controller_server and nav2_smoother from cmd_vel_nav to cmd_vel_raw.

from navigation2.

Hi Steve thanks for your attention on this question.

I'm encountering an issue with visualizing polygons using the default QoS settings.

When I launch the collision monitor node first, the polygons always appear without issues, provided I set the Durability QoS to transient_local. This setting ensures that the data is retained and available to late-joining subscribers. Here's a screenshot of the working setup:

There is one **interesting detail ** that I have noticed: If I launch the collision monitor node first then the polygons always appear with no issues, (although must be mandatory to set the Durability QoS to transient_local).

When I set both to transient_local it works:

However, if I launch the simulation first and then the collision monitor node, the behavior becomes unstable. The polygons do not always appear; sometimes only polygon_stop appears, and other times neither of them show up. Despite this, the messages seem to be sent correctly, as echoed in the terminal, but they are not visualized properly:

Chuck commented on my issue on robotics stack exchange

"When I followed the link to the tutorial you were using, I saw this statement: Both polygon shapes in the tutorial were set statically. However, there is an ability to dynamically adjust them over time using topic messages containing vertices points for polygons or footprints. For more information, please refer to the configuration guide. which sounds to me like it exactly describes what you're seeing - you get a single static polygon that does not adjust over time. Have you tried testing with dynamic polygons?"

I believe this is the last behavior I need to fix. I want the polygons to dynamically follow my robot's base_footprint. Unfortunately, I did not understand how to set the parameters and launch file for dynamic behavior from the documentation how to set the parameters and launch file to get the dynamic behavior (In Alexey tutorial video I have not checked any additional steps required to set on configuration file). Could you help me configure this to achieve dynamic polygon behavior?

from navigation2.

Thanks Steve!

You were correct the issue relied on using the cmd_vel_raw instead cmd_vel_nav in navigation.launch because I was following the Alexey tutorial but without following the context...

So you'd see only the single polygon from the initial state, which was not updated. It gets updated by a re-subscribe since its in the base_footprint frame, so when it gets the new data, rviz automatically converts it into your visualizer's fixed frame.

This subscription relation to cmd_vel also explains why the polygon boxes appear on rviz2 after the robot starts moving!

If you echo and it appears once and not a live stream, it means the collision monitor itself is not receiving command velocity data and you should review the configuration guide or main examples for setting up the collision monitor: https://docs.nav2.org/configuration/packages/configuring-collision-monitor.html

Finally the data flow is dynamic: https://youtu.be/vnL7_CqBup8

from navigation2.