xiaoqiang@cc:~$ rostopic hz /scan
subscribed to [/scan]
average rate: 9.999
min: 0.100s max: 0.100s std dev: 0.00004s window: 10
average rate: 9.996
min: 0.100s max: 0.101s std dev: 0.00016s window: 20
average rate: 9.999
min: 0.099s max: 0.101s std dev: 0.00019s window: 30
这个是SCAN发布的频率信息。
header:
seq: 809
stamp:
secs: 1547886482
nsecs: 454692793
frame_id: “lidar_link”
angle_min: -1.57000005245
angle_max: 1.57000005245
angle_increment: 0.0313999988139
time_increment: 2.49999999369e-07
scan_time: 9.50000030571e-05
range_min: 0.0
range_max: 100.0
ranges: [809.0, 809.0, 809.0, 809.0, 809.0, 809.0, 809.0, 809.0, 809.0, 809.0, 809.0, 809.0, 809.0, 809.0, 809.0, 809.0, 809.0, 809.0, 809.0, 809.0, 809.0, 809.0, 809.0, 809.0, 809.0, 809.0, 809.0, 809.0, 809.0, 809.0, 809.0, 809.0, 809.0, 809.0, 809.0, 809.0, 809.0, 809.0, 809.0, 809.0, 809.0, 809.0, 809.0, 809.0, 809.0, 809.0, 809.0, 809.0, 809.0, 809.0, 809.0, 809.0, 809.0, 809.0, 809.0, 809.0, 809.0, 809.0, 809.0, 809.0, 809.0, 809.0, 809.0, 809.0, 809.0, 809.0, 809.0, 809.0, 809.0, 809.0, 809.0, 809.0, 809.0, 809.0, 809.0, 809.0, 809.0, 809.0, 809.0, 809.0, 809.0, 809.0, 809.0, 809.0, 809.0, 809.0, 809.0, 809.0, 809.0, 809.0, 809.0, 809.0, 809.0, 809.0, 809.0, 809.0, 809.0, 809.0, 809.0, 809.0]
intensities: [909.0, 909.0, 909.0, 909.0, 909.0, 909.0, 909.0, 909.0, 909.0, 909.0, 909.0, 909.0, 909.0, 909.0, 909.0, 909.0, 909.0, 909.0, 909.0, 909.0, 909.0, 909.0, 909.0, 909.0, 909.0, 909.0, 909.0, 909.0, 909.0, 909.0, 909.0, 909.0, 909.0, 909.0, 909.0, 909.0, 909.0, 909.0, 909.0, 909.0, 909.0, 909.0, 909.0, 909.0, 909.0, 909.0, 909.0, 909.0, 909.0, 909.0, 909.0, 909.0, 909.0, 909.0, 909.0, 909.0, 909.0, 909.0, 909.0, 909.0, 909.0, 909.0, 909.0, 909.0, 909.0, 909.0, 909.0, 909.0, 909.0, 909.0, 909.0, 909.0, 909.0, 909.0, 909.0, 909.0, 909.0, 909.0, 909.0, 909.0, 909.0, 909.0, 909.0, 909.0, 909.0, 909.0, 909.0, 909.0, 909.0, 909.0, 909.0, 909.0, 909.0, 909.0, 909.0, 909.0, 909.0, 909.0, 909.0, 909.0]

这个是模拟的数据
xiaoqiang@cc:~$ rostopic list
/cmd_vel
/joint_states
/map
/map_metadata
/move_base/ADDWAPlannerROS/cost_cloud
/move_base/ADDWAPlannerROS/currentlocal_plan
/move_base/ADDWAPlannerROS/global_plan
/move_base/ADDWAPlannerROS/local_plan
/move_base/ADDWAPlannerROS/parameter_descriptions
/move_base/ADDWAPlannerROS/parameter_updates
/move_base/ADDWAPlannerROS/trajectory_cloud
/move_base/NavfnROS/plan
/move_base/StatusFlag
/move_base/cancel
/move_base/current_goal
/move_base/feedback
/move_base/global_costmap/costmap
/move_base/global_costmap/costmap_updates
/move_base/global_costmap/footprint
/move_base/global_costmap/inflation_layer/parameter_descriptions
/move_base/global_costmap/inflation_layer/parameter_updates
/move_base/global_costmap/obstacle_layer/parameter_descriptions
/move_base/global_costmap/obstacle_layer/parameter_updates
/move_base/global_costmap/parameter_descriptions
/move_base/global_costmap/parameter_updates
/move_base/global_costmap/static_layer/parameter_descriptions
/move_base/global_costmap/static_layer/parameter_updates
/move_base/goal
/move_base/local_costmap/costmap
/move_base/local_costmap/costmap_updates
/move_base/local_costmap/footprint
/move_base/local_costmap/inflation_layer/parameter_descriptions
/move_base/local_costmap/inflation_layer/parameter_updates
/move_base/local_costmap/obstacle_layer/parameter_descriptions
/move_base/local_costmap/obstacle_layer/parameter_updates
/move_base/local_costmap/parameter_descriptions
/move_base/local_costmap/parameter_updates
/move_base/parameter_descriptions
/move_base/parameter_updates
/move_base/result
/move_base/status
/move_base_simple/goal
/odom
/rosout
/rosout_agg
/scan
/send_movebase_cmd/receive_cmd
/tf
/tf_static
这个是启动的节点。
我没有看出问题来，但是速度快了就不行了

我启动的是xiaoqiang_udrf.launch，cc_fake_move_base_blank_map.launch，然后模拟了里程和激光雷达数据，这个消息应该是costmap_2d报出来的，如果expected_update_rate改为0,就没有警告了，

我虚拟了一个激光数据， 发布频率是10HZ，发布的话题是"scan"，
move_base costmap_common_params.yaml参数如下
base_scan: {data_type: LaserScan, topic: /scan, observation_persistence: 0.0, marking: true, clearing: true, expected_update_rate: 0.5}，更新的频率为：0.5.
但是move_base启动起来之后，一直报这个警告：
The /scan observation buffer has not been updated for 0.86 seconds,
里面的没有更新的时间最多0.9秒，不知道是怎么回事？
我的激光数据发布已经够快了，base_scan更新的频率也不太快，是0.5s，，为什么还会出现这个警告那？
谢谢