ubuntu18.04+melodic,在执行roslaunch mbot_gazebo view_mbot_gazebo_play_ground.launch指令时候报错，显示不了机器人，想问下是什么原因呢？

网上查了很多资料也没有解决，求助！万分感谢！

mbot1
 
 
Picture1
 
 

process[urdf_spawner-6]: started with pid [27898]
Traceback (most recent call last):
File “/opt/ros/melodic/lib/gazebo_ros/spawn_model”, line 34, in <module>
from tf.transformations import quaternion_from_euler
File “/opt/ros/melodic/lib/python2.7/dist-packages/tf/__init__.py”, line 30, in <module>
from tf2_ros import TransformException as Exception, ConnectivityException, LookupException, ExtrapolationException
File “/home/xiu/catkin_ws1/devel/lib/python2.7/dist-packages/tf2_ros/__init__.py”, line 34, in <module>
exec(__fh.read())
File “<string>”, line 38, in <module>
File “/home/xiu/catkin_ws1/devel/lib/python2.7/dist-packages/tf2_py/__init__.py”, line 34, in <module>
exec(__fh.read())
File “<string>”, line 38, in <module>
ImportError: dynamic module does not define init function (init_tf2)
[urdf_spawner-6] process has died [pid 27898, exit code 1, cmd /opt/ros/melodic/lib/gazebo_ros/spawn_model -urdf -model mrobot -param robot_description __name:=urdf_spawner __log:=/home/xiu/.ros/log/bc97595e-783e-11eb-97ff-84c5a6c83935/urdf_spawner-6.log].