A mini-project to better explain pub-sub architecture in ROS

Make sure you have all the required ROS packages installed, and that this package is in your ROS workspace (assumed ot be ~/catkin_ws.

$ cd ~/catkin_ws
$ rosdep install --from-paths src --ignore-src --rosdistro=kinetic -y

If you have not built your workspace do it now (make sure you are inside the workspace root directory):

$ catkin_make

Once the simple_arm package has been built, you can launch the simulation environment using:

$ source ~/catkin_ws/devel/setup.bash
$ roslaunch simple_arm robot_spawn.launch

Please note that if you are having trouble with roslaunch simple_arm robot_spawn.launch please try the safe_spawner.sh script in the scripts folder. You can launch by using $ ./safe_spawner.sh in a terminal of your choice

Robot can be controlled by publishing joint values to joint controller topics:

/simple_arm/joint_1_position_controller/command
/simple_arm/joint_2_position_controller/command

In a separate terminal type this command to control joint_1:

$ rostopic pub -1 /simple_arm/joint_1_position_controller/command std_msgs/Float64 "data: 1.5"

To control joint_2:

$ rostopic pub -1 /simple_arm/joint_2_position_controller/command std_msgs/Float64 "data: 1.5"

Note: Change the value of "data" argument to change joint_position values.

Camera image stream is published to following topic:

/rgb_camera/image_raw

This stream can be viewed by folliwng command in separate terminal:

$ rosrun image_view image_view image:=/rgb_camera/image_raw

If you encounter an error and gazebo crashes while vieweing camera stream, you need to upgrade gazebo7 to gazebo7.6:

$ sudo sh -c 'echo "deb http://packages.osrfoundation.org/gazebo/ubuntu-stable `lsb_release -cs` main" > /etc/apt/sources.list.d/gazebo-stable.list'
$ wget http://packages.osrfoundation.org/gazebo.key -O - | sudo apt-key add -
$ sudo apt-get update
$ sudo apt-get install gazebo7