個人感覺是python2與python3在ros中的差異導致的，

問題一：Traceback (most recent call last):
  File "/usr/bin/rosdep", line 3, in <module>
    from rosdep2.main import rosdep_main

ImportError: No module named 'rosdep2'

解決：sudo apt-get install python3-rosdep

問題二：pkg_resources.DistributionNotFound: The 'catkin-pkg==0.4.9' distribution   was not found

解決：

pip install catkin-tools

pip install rospkg

可參考http://www.cnblogs.com/h46incon/p/6207145.html