Can I install Robotic Operating System (ROS) on Raspberry Pi?
I have seen the web page Setting up ROS on Raspberry Pi. It didn't make any sense to me, and I coudn't understand it.
Yes, you can and yes, it is more complicated then doing that in Ubuntu. The major issue here is not Raspberry Pi itself (although some ROS packages are not available for the ARM architecture) but the usually used Raspbian. Frankly setting up ROS on a normal desktop Debian is a lot harder then on an Ubuntu desktop due to the many old packages in there and the fact that you are forced to compile a lot of things on your own just to get it running. ROS officially supports only Ubuntu. The article you have found works but it's as bad (wasting time to install the thing) as with a normal Debian installation. If you decide to do that anyways I strongly recommend cross-compilation with your PC doing the compiling and linking and your RPi doing the execution of the binaries. Otherwise you are up for several hours of compilation on the RPi and this is just to get the basics. I tried it and it was a waste of time -> cross-compilation for the win!
Now you can install ROS quite easily on Raspberry pi following the instructions: Installing ROS Indigo on Raspberry Pi. I installed it successfully on a Raspberry Pi A+, but only the basic libraries (ROS-Comm), not the Desktop version (rqt, rviz).