Mantis

Mantis is an autonomous differential drive robot with two wheels. Its main processing unit is a Jetson Nano running Ubuntu Mate 20.04 and the ROS 1 (ROS Noetic) middleware. This respository contains ROS driver packages, ROS Control Hardware Interface for the real robot and configurations for simulating Mantis.

Gazebo Simulation

It provides mounts for different camera modules, such as Realsense D435 and you can even design your own if you like. There is also support for different single board computers (Nvidia Jetson Nano) through two changable decks.

Package: Package Overview

• mantis_base: ROS Control hardware interface including controller_manager control loop for the real robot. The scripts folder of this package contains the low-level base_controller that is running on the Teensy microcontroller.
• mantis_bringup: Launch files to bring up the hardware drivers (camera, lidar, imu, ultrasonic, ...) for the real mantis robot.
• mantis_control: Configurations for the diff_drive_controller of ROS Control used in Gazebo simulation and the real robot.
• mantis_description: URDF description of mantis including its sensors.
• mantis_gazebo: Simulation specific launch and configuration files for mantis.
• mantis_msgs: Message definitions specific to mantis, for example the message for encoder data.
• mantis_navigation: Navigation based on move_base package; launch and configuration files.
• mantis_slam: Simultaneous localization and mapping using different implementations (e.g., gmapping) to create a map of the environment

Dependencies

The required Ubuntu packages are listed in software package sections found in the documentation. Other ROS catkin packages such as rplidar_ros need to be cloned into the catkin workspace.

For an automated and simplified dependency installation process install the vcstool, which is used in the next steps.

sudo apt install python3-vcstool

How to Build

To build the packages in this repository including the Remo robot follow these steps:

1. cd into an existing ROS Noetic catkin workspace or create a new one:

   mkdir -p catkin_ws/src

2. Clone this repository in the src folder of your ROS Noetic catkin workspace:

   cd catkin_ws/src

   git clone https://github.com/Aakash872/mantis

3. Execute the vcs import command from the root of the catkin workspace and pipe in the mantis_dev.repos or remo_robot.repos YAML file, depending on where you execute the command, either the development PC or the SBC of Remo to clone the listed dependencies. Run the following command only on your development machine:

   vcs import < src/mantis/mantis_dev.repos
   ```roslaunch mantis_navigation mantis.launch
   
   
   

4. Install the requried binary dependencies of all packages in the catkin workspace using the following rosdep command:

   rosdep install --from-paths src --ignore-src -r -y
   

5. After installing the required dependencies build the catkin workspace, either with catkin_make:

   catkin_ws$ catkin_make

   or using catkin-tools:

   catkin_ws$ catkin build

6. Finally, source the newly built packages with the devel/setup.* script, depending on your used shell:

   For bash use:

   catkin_ws$ source devel/setup.bash

   For zsh use:

   catkin_ws$ source devel/setup.zsh

Usage

The following sections describe how to run the robot simulation and how to make use of the real hardware using the available package launch files.

Gazebo Simulation with ROS Control

Control the robot inside Gazebo and view what it sees in RViz using the following launch file:

roslaunch mantis_control mantis.launch

This will launch the default mantis world turtlebot3_world.world.

turtlebot3_world.world

Navigation

To navigate the robot in the Gazebo simulator in turtlebot3_world.world run the command:

roslaunch mantis_navigation mantis.launch

This uses a previously mapped map of turtlebot3_world.world (found in mantis_navigation/maps) that is served by the map_server. With this you can use the 2D Nav Goal in RViz directly to let the robot drive autonomously in the turtlebot3_world.world.

SLAM

To map a new simulated environment using slam gmapping, first run

roslaunch mantis_gazebo mantis.launch world_name:='$(find mantis_gazebo)/worlds/turtlebot3_world.world'

and in a second terminal execute

roslaunch mantis_slam mantis_slam.launch slam_method:=gmapping

Then explore the world with the teleop_twist_keyboard or with the already launched rqt_robot_steering GUI plugin:

When you finished exploring the new world, use the map_saver node from the map_server package to store the mapped enviornment:

rosrun map_server map_saver -f ~/map

Navigating and Mapping on the real Robot

Start by setting up the ROS Network, by making the development PC the rosmaster set the ROS_MASTER_URI environment variable accordingly, Then follow the steps listed below to run the real mantis or Remo robot hardware:

1. First, brinup the robot hardware including its laser with the following launch file from the mantis_bringup package. Make sure to run this on the real robot (e.g. connect to it via ssh):

   roslaunch mantis_bringup bringup_with_laser.launch

2. Then, in a new terminal on your remote/work development machine (not the single board computer) run the slam gmapping with the same command as in the simulation:

   roslaunch mantis_slam mantis_slam.launch slam_method:=gmapping

   As you can see in the video, this should open up RViz and the rqt_robot_steering plugin.

3. Next, steer the robot around manually either using the keyboard_teleop node or using the rqt_robot_steering node and save the map with the following command when you are done exploring:

   rosrun map_server map_saver -f real-world

After the mapping process it is possible to use the created map for navigation, after running the following launch files:

1. On the single board computer (e.g. Jetson nano) make sure that the following is launched:

   roslaunch mantis_bringup bringup_with_laser.launch

2. Then on the work/remote development machine run the mantis_hw.lauch from the mantis_navigation package:

   roslaunch mantis_navigation mantis_hw.lauch

   Among other essential navigation and map server nodes, this will also launch an instance of RViz on your work pc where you can use its tools to:

   1. Localize the robot with the "2D Pose Estimate" tool (green arrow) in RViz
   2. Use the "2D Nav Goal" tool in RViz (red arrow) to send goals to the robot

References