Author: Roberto Zegers R.

This package contains a URDF model of a differential drive robot equipped with a camera and laser sensor.

• Image Topic: /udacity_bot/camera1/image_raw
• Image Info Topic:/udacity_bot/camera1/camera_info
• Laser Scan Topic: /udacity_bot/laser/scan
• Odometry Topic: /odom
• Movement Commands: /cmd_vel

To spaw the robot into a running Gazebo simulation with a custom Odometry Topic append an argument like this:
$ roslaunch udacity_bot spawn_udacity_bot.launch odometryTopic:=odom_perfect

• urdf/ : (required) contains the files that generate the robot model and provide simulated actuators and sensors
• meshes/ : (required) contains the mesh files of the laser sensor
• config/ : (optional) contains YAML files that store the Navigation Stack configuration files for the robot
• rviz/ : (optional) contains Rviz configuration settings for displaying the robot model
• launch/ : (optional) contains launch files for starting the simulation / running nodes
• worlds/ : (optional) contains scene/environment files for Gazebo
• maps/ : (optional) contains the occupancy grid based maps required for navigation

• udacity_bot.xacro : the xacro file that generates the urdf description file of the robot
• udacity_bot.gazebo : contains the Gazebo plugins that provide an interface to control the robot wheels and simulate the laser sensor

• Clone this repository into a ROS catkin workspace
• Build and source the workspace
• To view this robot model on an empty Gazebo world: $ roslaunch udacity_bot empty_world.launch
• To launch this package including the Jackal Race Gazebo world and Rviz: $ roslaunch udacity_bot udacity_world.launch use_rviz:=true
  or:
• To spawn the robot into another already opened Gazebo world:
  $ roslaunch udacity_bot spawn_udacity_bot.launch

If you want to move the robot using a keyboard you will also need to start a teleop node.
To run the AMCL localization node and use the robot with the Navigation Stack type in a new window: roslaunch udacity_bot amcl.launch

To view raw images on the topic /camera/rgb/image_raw, use:
$ rosrun image_view image_view image:=/udacity_bot/camera1/image_raw

First check that you satisfy all dependencies by running: $ rospack find gmapping
You can use this robot to build a map since it includes the required odometry and laser sensor. The inluded launch file mapping.launch will start Gazebo, load a predetermined world, and start the package gmapping properly configured, along with all other nodes required, including Rviz.
To move the robot around a telop node is also required, for instance you can use:
$ rosrun rqt_robot_steering rqt_robot_steering
At the beginning there could be no map in Rviz, you may need to wait few second until it is generated.

• Gazebo is crashing as it is starting up: Usually, it is enough to run it again (probably several times).
• Most of the visual robot model shapes are not shown or are displayed collapsed on Rviz: make sure to run robot_state_publisher to publish transforms for all joints.
  Do it by running roslaunch udacity_bot robot_description.launch

This package has only been tested on Ubuntu 16.04 LTS with ROS Kinetic and Gazebo 7.0 and 7.15.