[ros-users] Navigation stack: issue about ground plane detection

[clarkwu]

Hi, all,

I am experimenting the navigation stack on our self-made omni robot. A tilt
laser is installed and its separate testing is ok, i.e., the result of
laser_filter and laser_snapshotter all look fine in rviz. Then I followed
the setting under pr2_2dnav package, and try to run the whole navigation
stack.

I keep getting such warning info:
......
[ WARN] [1287143693.077180348]: The /ground_object_cloud observation buffer
has not been updated for 37.21 seconds, and it should be updated every 0.20
seconds.
[ WARN] [1287143693.177130903]: The /ground_object_cloud observation buffer
has not been updated for 37.31 seconds, and it should be updated every 0.20
seconds.
[ WARN] [1287143693.277171334]: The /ground_object_cloud observation buffer
has not been updated for 37.41 seconds, and it should be updated every 0.20
seconds.
[ WARN] [1287143693.377600991]: The /ground_object_cloud observation buffer
has not been updated for 37.51 seconds, and it should be updated every 0.20
seconds.
[ WARN] [1287143693.477116087]: The /ground_object_cloud observation buffer
has not been updated for 37.61 seconds, and it should be updated every 0.20
seconds.
[ WARN] [1287143693.495417506]: The /ground_object_cloud observation buffer
has not been updated for 42.22 seconds, and it should be updated every 0.20
seconds.
......

the above /ground_object_cloud observation is included in the following
costmap_common_params.yaml file:
--------------------------
map_type: voxel
origin_z: 0.0
z_resolution: 0.1 
z_voxels: 16
obstacle_range: 2.5
raytrace_range: 3.0
robot_radius: 0.25
inflation_radius: 0.3
inscribed_radius: 0.25
circumscribed_radius: 0.3

observation_sources: base_scan_filtered base_laser_scan tilt_scan
ground_object_cloud
base_scan_filtered: {sensor_frame: baselaser_link, topic:
/base_laser/scan_filtered, data_type: PointCloud, expected_update_rate: 0.2,
  observation_persistence: 0.0, marking: true, clearing: false,
min_obstacle_height: 0.08, max_obstacle_height: 2.0}
base_laser_scan: {sensor_frame: baselaser_link, data_type: LaserScan, topic:
/base_laser/scan, marking: true, clearing: true}
tilt_scan: {sensor_frame: laser_tilt_mount_link, topic: /tilt_laser/scan,
data_type: LaserScan, expected_update_rate: 0.2,
             observation_persistence: 0.2, marking: false, clearing: true,
min_obstacle_height: -20.00, max_obstacle_height: 40.0}
ground_object_cloud: {sensor_frame: laser_tilt_mount_link, topic:
/ground_object_cloud, data_type: PointCloud, expected_update_rate: 0.2,
                       observation_persistence: 4.6, marking: true,
clearing: false, min_obstacle_height: -0.10, max_obstacle_height: 2.0}


and the topic: /ground_object_cloud is supposed to be generated by the
sac_inc_ground_removal_node, as included in the launch file
ground_plance.xml:
-----------------------------
<launch>
	<node name="ground_object_cloud_throttle" pkg="topic_tools" type="throttle"
args="messages ground_object_cloud 3.0 ground_object_cloud_throttled" />

	<node pkg="semantic_point_annotator" type="sac_inc_ground_removal_node"
name="sac_ground_removal" >
	  <remap from="tilt_laser_cloud_filtered" to="tilt_scan_cloud" />
	  <remap from="cloud_ground_filtered" to="ground_object_cloud" />
	  
	  	  
	  
	  
	  
	  
	</node>
</launch>

The weired thing is, for the above node, the input tilt_scan_cloud is
confirmed existing, yet the output ground_object_cloud never generate, as
observed in rviz and by the command line rostopic echo /ground_object_cloud.

I am suspecting there is something wrong with the above process. I tried add
two lines in the source file  sac_inc_ground_removal_standalone.cpp, to suit
for my case where base_link is used as alternative for
robot_footprint_frame, yet no effect:
      node_.getParam ("robot_footprint_frame", robot_footprint_frame_);
      node_.getParam ("laser_tilt_mount_frame", laser_tilt_mount_frame_);


any hints?  thanks

xiaojun
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