Embedded Motion Control 2013/Installation

This manual describes how to the install the necessary and sufficient software to start programming the Pico robot.

Ubuntu

Go to The official Ubuntu site and download and install Ubuntu 12.04, which is the latest Long Term Support release. Make sure that you download the appropriate architecture i.e., 32- or 64-bit. Of course you can also bring your notebook to the ICT servicedesk and ask them to install Ubuntu. If you want to keep using Windows next to Ubuntu the most easy way is to have a dual-boot system, i.e., during startup you can choose to boot either Ubuntu or Windows.

Ubuntu Terminal

Most of your interaction with Ubuntu will be done through the terminal, the number-one way of interacting with Ubuntu using your keyboard. A terminal can be started as follows: Application -> Accessories -> Terminal, or by pressing ctrl-alt-t. It might be a good idea to drag the terminal icon in the menu to the Ubuntu panel, as you will be using it a lot. Read more

ROS

In this project we will use the Robotic Operating System (ROS) which aids the testing and development of robot software. ROS provides a nice open-source framework for dealing with the communication between and management of different modules, and comes with a large amount of software that can be used out of the box, including device drivers, libraries, low- and high-level software, visualizers and more. More information about ROS and its goals can be found here.

We will be using ROS Groovy. Install ROS Groovy using the installation instructions on the [| ROS wiki]. After the installation, you should do the ROS tutorials. The ROS tutorial can be found here. In some of the tutorials you can choose between catkin and rosbuild (for example in [| this tutorial]. Make sure you select rosbuild (above the content text box).

Before you continue, make sure you understand the basic ROS concepts, such as:

• package
• node
• topic
• subscriber
• publisher
• message
• callback function
• ...

In addition it is important to know the concept of the ROS_PACKAGE_PATH. ROS_PACKAGE_PATH is a variable which informs ROS on the location of your packages. ROS will only be able to find packages which are located in a folder which is part of your package path! To print the value of the ROS_PACKAGE_PATH variable, you can simply type:

echo $ROS_PACKAGE_PATH

in a terminal.

SVN

In this project, an SVN will be used for sharing and versioning the software within your group. Every group has its own space on the SVN, and an account which has only permissions for that particular part. Make sure you read the following SVN instruction carefully! Not reading them might cost you a lot of time in the end!

Environment Set-up

So far we've installed ROS and created a local copy of the SVN. However, before you can start working, you need to do some additional set-ups to make sure Ubuntu knows where to find all ROS-related packages, scripts, etc. More specifically, every time you start up a terminal, the correct environment variables need to be set. The file .bashrc in your home directory is your friend: it's a script which runs every time a a new terminal is opened. We basically need to add some lines to this file, so open the file with a text editor:

gedit ~/.bashrc

Append the following text to the end of the file:

source /opt/ros/fuerte/setup.bash

This will set-up all ROS-related scripts etc. every time you open a terminal. Furthermore, ROS needs to known where your software is located. Therefore, also add the following command to ~/.bashrc:

export ROS_PACKAGE_PATH=~/ros/emc:$ROS_PACKAGE_PATH

That's it. Next time you open a terminal, .bashrc is executed, which will in turn execute the script and set the path specified above. Since the script only runs when a new terminal is opened, the changes are not active in your current terminal. If you want to see it working directly without starting a new terminal, explicitly source .bashrc from the terminal:

source ~/.bashrc

To see whether it worked, try one of commands that are now at your disposal. For example, change your directory to the roscpp package:

roscd roscpp

Integrated Development Environments

To keep the code in your packages clear and manageable, it is advised to use an Integrated Development Environment (IDE) to edit your C++ code. Two editors that are commonly used are Qt Creator and Eclipse.

Qt Creator

Installation

Don't use the software center or apt-get to install Qt, then all this will not work properly. Just follow the steps below.

1. Download Qt Creator for Linux:
   • 32-bit
   • 64-bit
2. Open a terminal, cd to the folder where you downloaded the file (probably ~/Downloads)
3. Make the file executable:

   chmod +x <INSTALL_FILE>

4. Run the installation:

   ./<INSTALL_FILE>

5. Make sure Qt Creator launches with the ROS environment available:
   1. Open the launcher properties (right-click Applications -> Edit Menus -> Programming -> Qt Creator -> Properties
   2. In the 'Command' field, add bash -i -c in front of the existing command.

Now you can correctly launch Qt Creator from the menu.

Use with ROS

Creating a ROS package

To create a ROS package, follow the usual steps, i.e., use the roscreate-pkg command.

Open an existing ROS package

1. Make sure your package is in the ROS_PACKAGE_PATH
2. Start Qt Creator
3. File -> Open File or Project
4. Navigate to and open the CMakeLists.txt file of your package
5. Change the build directory into <YOUR_PACKAGE_DIR>/build (that is: a / instead of a -). Click 'Next'.
6. Click 'Run CMake'. This will automatically look for and include dependencies in the manifest.xml file, see which .cpp files you use, etc, based on your CMakeLists.txt.
7. Click 'Finish'

Now you are ready to start developing your code. Pressing Ctrl-b will build the active project. If you change the manifest.xml or CMakeLists.txt file, you only have to run CMake again (Build -> Run CMake).

Show header files in the 'Projects View'

Qt Creator only shows your .cpp files in the 'Project View', which can be a bit of a nuisance. To also show your header files, perform the following trick:

1. Open CMakeLists.txt
2. Add the following line before rosbuild_add_executable:

   file(GLOB_RECURSE HEADER_FILES include/*.h)

   This looks for all .h files in the include folder of your package, and stores them in the variable HEADER_FILES.
3. Add ${HEADER_FILES} to your rosbuid_add_executable list. For example:

   rosbuild_add_executable(my_program src/program.cpp ${HEADER_FILES})

4. Within Qt Creator, run CMake (Build -> Run CMake)

You should now be able to see all .h files in the include folder of your package.

Troubleshoot

CMake Error

If you try to open your project in Qt Creator and you get the following message when running CMake:

CMake Error: The current CMakeCache.txt directory <YOUR_PACKAGE>/build/CMakeCache.txt is different
than the directory <OTHER_DIR>/build where CMakeCache.txt was created. This may result in binaries
being created in the wrong place. If you are not sure, reedit the CMakeCache.txt

you have probably moved your package without cleaning it (make clean). This means the absolute paths that where generated during building do not make sense anymore. To solve this, do the following:

• Clean your project, i.e., run make clean
• Make sure there is no CmakeLists.txt.user in your package (it is auto-generated by Qt Creator)
• Try to open your project again

Eclipse

Eclipse is an IDE widely used for Java, C, C++ and many more languages. This section explains how it can be configured to be easily used with ROS packages.

To install Eclipse, do the following:

1. Go to the Eclipse download site
2. Find Eclipse IDE for C/C++ Developers and select the appropriate version on the right (32-Bit or 64-Bit Linux).
3. Extract Eclipse into a folder of your choice
4. You can create a launcher to Eclipse to your panel by alt + right clicking the panel, choosing 'Add to panel' and selecting 'Custom Application Launcher'. Then browse to the Eclipse executable, and enter a name. If you want you can add the Eclipse icon by clicking the image on the left and browsing to the icon in the Eclipse folder.

Now, to make sure your package can be viewed properly in Eclipse, do the following:

1. Create a custom package in your ~/ros directory with optional dependencies:

   cd ~/ros/emc

   roscreate-pkg <package-name> [dependencies...]

2. Enter in a terminal:

   roscd <package name>

   make eclipse-project

3. Open Eclipse
   • You will be prompted to select a path for the workspace. The default (/home/YOUR_NAME/workspace) is fine here. This folder will not contain the software (that is stored in ~/ros), but simply pointers to the software and some administration files for Eclipse.
4. Go to “file” → “Import”
5. Click “General”
6. Then “Existing Projects into Workspace”
7. Click “next”
8. Browse for the package

All environment settings should be set automatically. You can build the package using ctrl-b. Note that you have to remake the eclipse-project in your package every time you change the manifest or if you switch to a new version of ROS. If you're having trouble or want to know more about the possibilities of using eclipse with ROS, check the ROS wiki.

Gazebo

We will use the robot simulator [ http://gazebosim.org/ Gazebo ] to simulate the Jazz robot and its environment. This includes simulation of the physics and sensors of the robot. To install Gazebo:

1. Open a terminal (ctrl-alt-t)
2. Setup your computer to accept software from packages.osrfoundation.org:

   sudo sh -c 'echo "deb http://packages.osrfoundation.org/gazebo/ubuntu precise main" > /etc/apt/sources.list.d/gazebo-latest.list'

3. Retrieve and install the keys for the Gazebo repositories:

   wget http://packages.osrfoundation.org/gazebo.key -O - | sudo apt-key add -

4. Update apt-get and install Gazebo.

   sudo apt-get update

   sudo apt-get install gazebo

5. Initialize.

   gzserver

   Wait until you get a message like Publicized address: ....

You can try if your Gazebo installation was successfull by either executing a gazebo client on a seperate terminal:

gzclient

Or by running the program alone:

gazebo