Hello all,
I am developing a modular robotic arm, which will consist of the following parts:
- A PC running the motion planning (MoveIt & ros_control)
- Embedded controllers which run the local PID loops to control the arm's joints
My idea was to use SBC's (Single Board Computers) running linux as the embedded controllers, so for communication between the main PC and the embedded controllers the standard ROS infrastructure can be used.
Most of these SBC's have some ARM processor, so my initial guess would be to run a stripped down ARM Ubuntu version on the SBC's. However, Canonical seems to have stopped distributing ARM versions of Ubuntu, apart from their new distribution for embedded systems: Ubuntu snappy core. This would not be an issue, since there is a nice plugin to create snappy-compatible packages out of ROS workspaces with the catkin plugin for snapcraft. (see also: [this link](https://github.com/snapcore/snapcraft/blob/master/docs/ros-snap.md)). This would generate a stand-alone application that contains all ROS (and other) dependencies and is compatible with the snappy package system. (the main issue with the snappy distribution over the old ARM distributions is that you can no longer use apt-get to retrieve needed ROS packages, so the only way to get ROS on snappy is to either create a snappy package containing the ROS nodes and dependencies, or to install ROS from source)
But here is the catch:
- MoveIt is released up to ROS jade, running on Ubuntu 15.04 (Vivid) (but not on later ubuntu versions)
- Snapcraft is released only on Ubuntu 16.04 (Xenial), so this would correspond to ROS kinetic
As far as I know, mixing two ROS distributions is not recommended, so there would be couple options to get this working:
- Install MoveIt from source for kinetic on Ubuntu 16.04 (Xenial)
PC: Ubuntu 16.04 + Kinetic, Embedded: Ubuntu 16.04 Snappy Core
- Install ROS jade from source on Ubuntu 16.04 (Xenial) and create snappy packages from there
PC: Ubuntu 15.04 + Jade, Embedded: Ubuntu 16.04 Snappy Core, Build PC: Ubuntu 16.04 + Jade
- Install Snapcraft from source on Ubuntu 15.04 (Vivid) and create snappy packages from there
PC: Ubuntu 15.04 + Jade, Embedded: Ubuntu 16.04 Snappy Core
- Install ROS jade from source directly onto Ubuntu 16.04 Snappy Core (circumventing the snappy package system altogether)
PC: Ubuntu 15.04 + Jade, Embedded: Ubuntu 16.04 Snappy Core + Jade from source
Does any of you have any experience with this? Is this even feasible? Or would it be best to move to some other OS for the embedded controllers (one of the boards I am considering is the BeagleBone Black which can also run Debian or Angstrom for example (see also: [this link](http://elinux.org/Beagleboard:BeagleBoneBlack#Software_Resources)) which also has some unofficial ROS support). My preferred situation would be to use as much stable software as possible, preferably in the form of binary releases.
Thanks in advance!
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