When following “Tutorial 7. Path planning,” I ran into several errors and warnings. The fixes (?) I applied to them are detailed below. Even after the errors and most of the warnings have been resolved, the ROSbot (A) strays far from the global_plan Path, and (B) often runs into walls when navigating to a “2D Nav Goal,” despite the fact that the walls show up in the SLAM Map and the global_costmap Map. A brief experience with the physical ROSbot showed that it, too, deviated significantly from the global_plan Path. Is this behavior to be expected? If so, can you tell me why? If not, can you offer any suggestions for improving it?
Here are the messages I received when running the “Path planning” tutorial.
[ WARN] [1561746904.781913245, 2918.960000000]: Timed out waiting for transform from base_link to map to become available before running costmap, tf error: canTransform: target_frame map does not exist… canTransform returned after 2918.96 timeout was 0.1.
This one is unresolved.
[ WARN] [1561747609.753177997, 2935.010000000]: MessageFilter [target=map laser_frame ]: Dropped 100.00% of messages so far. Please turn the [ros.costmap_2d.message_notifier] rosconsole logger to DEBUG for more information.
I resolved this by removing
from this line in the launch file
<node if="$(arg use_rosbot)" pkg="tf" type="static_transform_publisher" name="laser_broadcaster" args="0 0 0 3.14 0 0 base_link laser_frame 100" />
Invalid roslaunch XML syntax: [Errno 2] No such file or directory: u’/home/mqm/ROSWorkspaces/catkin_ws/src/ROSbot/rosbot_description/src/rosbot_gazebo/launch/rosbot.launch’
I resolved this by changing
<include if="$(arg use_gazebo)" file="$(find rosbot_gazebo)/launch/rosbot.launch"/>
in the launchfile to
<include if="$(arg use_gazebo)" file="$(find rosbot_description)/launch/rosbot_gazebo.launch"/>