Rtabmap/MemoryThr and /map (occupancy grid)

[sandeepdutta]

Hello Mathieu,

We continue to use RABMAP successfully in our robot. As we start mapping larger spaces, we are experimenting
with the "Rtabmap/MemoryThr" parameter . We use Rtabmap to generate the occupancy grid which is use by the
NAV2 stack to compute global routing. When the node count reaches the MemoryThr parameter a new map is created
the occupancy grid switches to the new map (on the /map) does not show the full grid . Is there a way to merge and
make RTABMAP publish the full grid on the /map ? If not are there other ways we can achieve this.

Thank you
Sandeep

[matlabbe]

Parameters Rtabmap/MemoryThr and Rtabmap/TimeThr enable memory management of RTAB-Map. If you want to keep the global map, you would need to disable this and tune other parameters to reduce increasing processing time over time.

How to do navigation with memory management enabled is explained in this paper: https://arxiv.org/abs/2301.00050

[sandeepdutta]

Hello Mathieu,

Thank you for the link, it is a very interesting paper. We want to try the approach described in it. I understand that MPP
creates the local & global map and depends on ROS to navigate to the "edge" of the map to the end point created by
TPP .
I see the function computePath, can I assume that this function will start the TPP process ? Is the way to get the next point from TPP to call computePath again ? How to tell when the goal has been reached .

Thank you & Best Regards
Sandeep

[matlabbe]

The TPP planning process is started when goal_node or goal callbacks are called. The feedback to know if the goal has been reached or not is published on topic goal_reached topic. The parameter RGBD/GoalReachedRadius (default 0.5 m) can be modified to trigger farther or closer to the goal. Note that if use_action_for_goal is used, rtabmap will wait until nav2 says it reached the goal (based on its own criteria) or aborted before publishing the result on goal_reached. That script is an example of calling TPP indefinitively with some patrolling behavior.