04. Add a Package

Please note that the video above and text below describe a missing package. If you are using the provided workspace, rather than the VM, this package is included. The process for resolving missing packages has been retained since it is a common occurrence and useful for working in ROS environments.

Cloning the simple_arm Package

One of the biggest benefits of using ROS is that it has a really large community of users and developers, so there is a lot of code that you can use.

Let’s clone an existing package and add it to our newly created workspace.

You will start by navigating to the src directory and cloning the simple_arm package for this lesson from its github repo.

$ cd ~/catkin_ws/src
$ git clone https://github.com/udacity/simple_arm_01.git simple_arm

Building the simple_arm package

After the repo has finished cloning, you can change directory to the top-level of the ros workspace and build the new package.

$ cd ~/catkin_ws
$ catkin_make

I see a CMake Error. "Could not find a package configuration file provided by controller_manager"

Installing Missing Packages Using apt-get

I happen to know that controller_manager refers to a ROS package from ROS Control. We can fix this by installing the associated Debian package. If I didn't already know this, I would probably have to rely on a Google search to figure out the exact name of the package required.

$ sudo apt-get install ros-kinetic-controller-manager

Some students have had success using the following commands to install missing packages:

$ source devel/setup.bash 
$ rosdep install simple_arm

OK, now that we have the controller-manager package let’s try building again. I'm still in the top level directory, so I can just type “catkin_make” and hit enter.

$ catkin_make

Looks like the build worked. Great, that wasn't so bad. Let’s run some of this code that we just cloned!