Program “rcm” run error!

[tt2cloud]

Hello, I'm attempting to apply this algorithm to a seven-axis serial robot, but during runtime, the ROS terminal throws the following error:

Traceback (most recent call last):
  File "/home/yun/ws_robot/src/rm_robot/rcm-master/rcm_examples/python/rcm_example_node.py", line 12, in <module>
    action_server = rospy.get_param('action_server')
  File "/opt/ros/melodic/lib/python2.7/dist-packages/rospy/client.py", line 467, in get_param
    return _param_server[param_name] #MasterProxy does all the magic for us
  File "/opt/ros/melodic/lib/python2.7/dist-packages/rospy/msproxy.py", line 123, in __getitem__
    raise KeyError(key)
KeyError: 'action_server'

How can I resolve this error, or could you provide instructions for launching this project?
Thank you！