ROS报错：ERROR: cannot launch node of type [rqt_joint_trajectory_controller/rqt_joint_trajectory.......

详细报错：

ERROR: cannot launch node of type [rqt_joint_trajectory_controller/rqt_joint_trajectory_controller]: rqt_joint_trajectory_controller
ROS path [0]=/opt/ros/melodic/share/ros
ROS path [1]=/home/rosmelodic/catkin_ws/src
ROS path [2]=/opt/ros/melodic/share

问题怎么出现的：

这个问题出现在二次开发的机械臂手爪需要

mimic_joint_pluginhttps://github.com/roboticsgroup/roboticsgroup_gazebo_plugins这个插件，其中这个插件的安装方法是

git clone https://github.com/roboticsgroup/roboticsgroup_gazebo_plugins.git

在工作区catkin_ws的src中打开终端,进行克隆，然后回到工作区