# 3. Problem domain: Traffic network of Dubins cars¶

Often referred to as “the second domain,” the basic setting is navigation in a small network of roads with vehicles that follow unicycle-like dynamics.

## 3.1. Preparations¶

While below we include pointers to the main websites for dependencies, many are available via packages for your OS and may already be installed, especially if you have ROS on Ubuntu 14.04. Supported platforms are described in the Introduction.

### 3.1.1. Basic¶

There are two major variants of this benchmark: one based in simulation and another on a physical testbed. We begin with preparations appropriate for both.

On Ubuntu, Eigen can be obtained by installing the “libeigen3-dev” deb package (https://packages.debian.org/jessie/libeigen3-dev).

Several ROS packages for the Kobuki by Yujin Robot are required.

(forthcoming)

### 3.1.4. Supplementary prerequisites¶

As for the Problem domain: Scaling chains of integrators, there is code that is relevant but not required for this benchmark.

## 3.2. Tutorials¶

In the below code, $FMRBENCHMARK is the absolute path to a copy of the fmrbenchmark repository on your machine. ### 3.2.1. Launching a problem instance of the simulation variant¶ Create a catkin workspace. mkdir -p dubsim_workspace/src cd dubsim_workspace/src  At this step you should be in the root of your workspace, i.e., the directory named dubplay. Finally build everything, and launch the straightroad example. Create symbolic links to the ROS packages in the fmrbenchmark repository required for this example. ln -s$FMRBENCHMARK/domains/dubins_traffic/dub_sim
ln -s \$FMRBENCHMARK/domains/dubins_traffic/e-agents/wander


Build and install it within the catkin workspace.

cd ..
catkin_make install


Because the installation is local to the catkin workspace, before beginning and whenever a new shell session is created, you must first

source install/setup.zsh


where the source command assumes that you are using the Z shell; try setup.bash if you use Bash. Finally, launch a small static environment of two vehicles on a straight road segment.

roslaunch dub_sim straightroad.launch