how to solve it???

[MAKER-park]

jetbot@jetbot-desktop:~/ydlidar_ws$ roslaunch ydlidar_ros_driver X2.launch

... logging to /home/jetbot/.ros/log/2a4a9d98-2f34-11eb-9ef5-4a4c3afdeae9/roslaunch-jetbot-desktop-26860.log
Checking log directory for disk usage. This may take a while.
Press Ctrl-C to interrupt
Done checking log file disk usage. Usage is <1GB.

started roslaunch server http://192.168.219.128:40335/

SUMMARY

PARAMETERS

• /rosdistro: melodic
• /rosversion: 1.14.10
• /ydlidar_lidar_publisher/abnormal_check_count: 4
• /ydlidar_lidar_publisher/angle_max: 180.0
• /ydlidar_lidar_publisher/angle_min: -180.0
• /ydlidar_lidar_publisher/auto_reconnect: True
• /ydlidar_lidar_publisher/baudrate: 115200
• /ydlidar_lidar_publisher/device_type: 0
• /ydlidar_lidar_publisher/frame_id: laser_frame
• /ydlidar_lidar_publisher/frequency: 10.0
• /ydlidar_lidar_publisher/ignore_array:
• /ydlidar_lidar_publisher/intensity: False
• /ydlidar_lidar_publisher/invalid_range_is_inf: False
• /ydlidar_lidar_publisher/inverted: True
• /ydlidar_lidar_publisher/isSingleChannel: True
• /ydlidar_lidar_publisher/lidar_type: 1
• /ydlidar_lidar_publisher/port: /dev/ydlidar
• /ydlidar_lidar_publisher/range_max: 12.0
• /ydlidar_lidar_publisher/range_min: 0.1
• /ydlidar_lidar_publisher/resolution_fixed: True
• /ydlidar_lidar_publisher/reversion: False
• /ydlidar_lidar_publisher/sample_rate: 3
• /ydlidar_lidar_publisher/support_motor_dtr: True

NODES
/
base_link_to_laser4 (tf/static_transform_publisher)
ydlidar_lidar_publisher (ydlidar_ros_driver/ydlidar_ros_driver_node)

ROS_MASTER_URI=http://localhost:11311

ERROR: cannot launch node of type [ydlidar_ros_driver/ydlidar_ros_driver_node]: Cannot locate node of type [ydlidar_ros_driver_node] in package [ydlidar_ros_driver]. Make sure file exists in package path and permission is set to executable (chmod +x)
process[base_link_to_laser4-2]: started with pid [26895]
[ WARN] [1606318803.583059189]: Shutdown request received.
[ WARN] [1606318803.587212523]: Reason given for shutdown: [[/base_link_to_laser4] Reason: new node registered with same name]
[base_link_to_laser4-2] process has finished cleanly
log file: /home/jetbot/.ros/log/2a4a9d98-2f34-11eb-9ef5-4a4c3afdeae9/base_link_to_laser4-2*.log
all processes on machine have died, roslaunch will exit
shutting down processing monitor...
... shutting down processing monitor complete
done

this error print after not anything respone... why that... plz help me...

[yangfuyuan]

Make sure that the workspace environment variable settings take effect
source your_workspace_path/devel/setup.bash

After compiling, try the following command:
rospack profile