ROS报错：
DeserializationError cannot deserialize: unknown error handler name 'rosmsg' --- husky_velocity_controller spawn
解决方法：
sudo apt-get install ros-kinetic-genpy
原因：
The problem is that you are mixing older and newer Debian packages. you don't have the latest version of genpy yet.
dpkg -l | grep genpy shows version 0.6.7. But the newly installed version of ros-kinetic-rosbridge-suite was generated with the latest version of genpy and therefore expect it to be available.
简单的说，ros中的一些pkg的依赖pkg没有相对应的更新（虽然有但版本旧）。
