11-ros-dev.md

Guide to Cross Compilation for a Raspberry Pi

1. Start
2. Setup XCS and RPi
3. Setup RPi Network and SSH
4. Setup RPi Peripherals
5. Setup Cross-compile environment
6. Cross-compile and Install Userland
7. Cross-compile and Install OpenCV
8. Cross-compile and Install ROS
9. Compile and Install OpenCV
10. Compile and Install ROS
11. Remote ROS (RPi node and XCS master)
12. > ROS package development (RPi/XCS)
13. Compile and Install WiringPi

12. ROS package development (RPi/XCS)

TO BE UPDATED. GUIDE MIGHT STILL WORK.

The scripts to source the ROS-builds on both the RPi and VM expect paths in which a package is build. Both ros-native and ros-cross search for the devel* folders created bij the ROS builders.

For native building, packages need to be build in:

XCS~$ ~/build/ros/<packagename>

For cross compilation, packages need to be build in:

XCS~$ ~/ros/<packagename>_cross

After cross-compiling a package for the RPi, the ~/ros directory needs to be synchronised with the RPi via:

XCS~$ ~/rpicross_notes/scripts/sync-ros.sh

The source of a package can be located everywhere.

Prerequisites:

• VM and RPi Configured: setup and network
• Toolchain installed
• Repository downloaded
• ROS (cross)compiled: cross and native

Optional:

• Userland (for gpu-support)
• OpenCV (cross)compiled: cross and native (for vision-support)
• Perhiperals (for camera/i2c)
• ROS-port forwarding (for mixed support)

Native-compilation

1. Set correct paths for native compilation

   XCS~$ source ~/rpicross_notes/scripts/ros-native
   

2. Build package

   XCS~$ mkdir -p ~/build/ros/<packagename>
   XCS~$ cd ~/build/ros/<packagename>
   XCS~$ cmake <path>/<to>/<package>
   XCS~$ make
   

3. Update ROS-paths, so new package is included

   1. Via generic script:

      XCS~$ source ~/rpicross_notes/scripts/ros-native  <hostname> <rpiname>
      

      <hostname> and ` are optional and only needed when a RPi is used. See Testing.

   2. or, build package only:

      XCS~$ source ~/build/ros/<packagename>/devel/setup.bash
      

4. Assuming a roscore is running, the package can be started via rosrun:

   XCS~$ rosrun <packagename> <node>
   

Cross-compilation

1. Set correct paths for cross compilation

   XCS~$ source ~/rpicross_notes/scripts/ros-cross
   

2. Build package

   XCS~$ mkdir -p ~/ros/<packagename>
   XCS~$ cd ~/ros/<packagename>
   XCS~$ cmake \
       -DCMAKE_TOOLCHAIN_FILE=/home/pi/rpicross_notes/rpi-generic-toolchain.cmake \
       <path>/<to>/<package>
   XCS~$ make
   

3. Update RPi

    XCS~$ ~/rpicross_notes/scripts/sync-ros.sh <rpi-host>
   

   <rpi-host> is optional. When omitted, rpizero-local is used.

4. Assuming a roscore is running, the package can be started via rosrun:

   XCS~$ ssh rpizero-local
   RPi~$ rosrun <packagename> <node>
   

Mixed

When a mixed setup is used, e.g. when both the VM and RPi need to be active, the following command should be executed before logging-in to the RPi or starting a node on either the VM or RPi:

XCS~$ source ~/rpicross_notes/scripts/ros-native <hostname> <rpiname>

• <hostname>: hostname of device on which roscore runs.
  1. when VM: name of HOST~$
  2. when RPi: name of RPi

  detect the hostname with the hostname command

• <rpiname>: name of ssh-connection defined in ssh_config of the RPi