Colleagues,
In case it is useful to anyone, below are my notes on installing Robert Nelson's Ubuntu 18.04.2 image with ROS melodic and the robot control library (aka librobotcontrol) pre-installed on the Beaglebone Blue (BBBL). This is full binary installation of Ubuntu, ROS melodic, and the Beaglebone robotcontrol library; you do not need to do source installs.
Best Regards,
-LLW