Turtle-Bot Example

Table of Contents

• 1. Setup the environment
  • 1.1. Hardware setup
    • 1.1.1. Setup raspberry pi for TurtleBot
  • 1.2. Driver setup
    • 1.2.1. Build the Driver on TurtleBot Raspberry Pi
• 2. Run client
• 3. Configure SLAMBOX Configurations
• 4. Hardware connection
  • 4.1. Serial Connection
• 5. Custom usage for SLAMBOX data
  • 5.1. Subscriber example for SLAMBOX data
  • 5.2. Save PCD data

1. Setup the environment

• Setup environment for communication with SLAMBOX and turtlebot

1.1. Hardware setup

1.1.1. Setup raspberry pi for TurtleBot

• Build Driver with local ROS, please use ROS version noetic (Installation)
• NOTE: We prefer you to use docker because the Debian OS version which supports ROS noetic is out of date

How to install docker in RPi Debian OS

• Official Docker installation website

1. Uninstall the installed old version docker

   # Uninstall the installed old version Docker
   for pkg in docker.io docker-doc docker-compose podman-docker containerd runc; do sudo apt-get remove $pkg; done

2. Set up docker's apt repository

   # Add Docker's official GPG key:
   sudo apt-get update
   sudo apt-get install ca-certificates curl gnupg
   sudo install -m 0755 -d /etc/apt/keyrings
   curl -fsSL https://download.docker.com/linux/debian/gpg | sudo gpg --dearmor -o /etc/apt/keyrings/docker.gpg
   sudo chmod a+r /etc/apt/keyrings/docker.gpg
    
   # Add the repository to Apt sources:
   echo \
     "deb [arch="$(dpkg --print-architecture)" signed-by=/etc/apt/keyrings/docker.gpg] https://download.docker.com/linux/debian \
     "$(. /etc/os-release && echo "$VERSION_CODENAME")" stable" | \
     sudo tee /etc/apt/sources.list.d/docker.list > /dev/null
   sudo apt-get update

3. Install the Docker packages

   sudo apt-get install docker-ce docker-ce-cli containerd.io docker-buildx-plugin docker-compose-plugin

4. Verity that the installation is successful by running the hello-world image

   sudo docker run hello-world

5. Give permission to user to use docker w/o sudo

   # Create the docker group
   sudo groupadd docker
    
   # Add your user to the docker group
   sudo usermod -aG docker $USER
    
   # Log out and log back in so that your group membership is re-evaluated.
   newgrp docker
    
   # Check the authority
   docker run hello-world

6. (Optional) Install ducker to use docker easier

   curl https://raw.githubusercontent.com/JeiKeiLim/ducker/main/install.sh | bash -s install linux arm64

1.2. Driver setup

1.2.1. Build the Driver on TurtleBot Raspberry Pi

• Should build the driver on TurtleBot raspberry pi for get data from SLAMBOX with ROS message
• Please check the README for building SLAMBOX driver

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2. Run client

• The SLAMBOX driver for server will be launched automatically.
• To check the result of SLAMBOX, use Remote server of turtlebot to run rviz
• NOTE: The RPi of turtlebot and the remote server must be connected with same network
• NOTE: The command below should be type inside the docker container

# 1. Set the ROS master ip of Remote server
$ export ROS_MASTER_URI=http://{remote_server_ip}:11311
$ export ROS_HOSTNAME={remote_server_ip}
 
# 2. Turn on the roscore
$ roscore
 
# 3. launch ros core and rviz
$ rviz -d {SLAMBOX_driver_dir}/docs/examples/turtlebot/config/rviz.rviz

• Set the remote server ip to turtlebot Raspberry Pi
• If the remote server ip is 192.168.0.3 the ROS_MASTER_URI will be http://192.168.0.3:11311

# if using docker, the command below run inside the docker
# 1. Setup the master ip of ROS and the host name
$ export ROS_MASTER_URI=http://{remote_server_ip}:11311
$ export ROS_HOSTNAME={turtlebot_rpi_ip}
 
$ source devel/setup.bash
$ roslaunch slambox_driver slambox_driver_client.launch

3. Configure SLAMBOX Configurations

• Check the SLAMBOX setting

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4. Hardware connection

4.1. Serial Connection

• To make the serial communication module, connect the pins of module like below

Image from https://www.vectornav.com

• Connect SLAMBOX with TurtleBot RPi, use serial module and connect like below

Serial with flexlam and turtlebot3 rpi

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5. Custom usage for SLAMBOX data

5.1. Subscriber example for SLAMBOX data

#include <ros.h>
#include <nav_msgs/Odometry.h>
#include <sensor_msgs/PointCloud2.h>
 
// There are two major data from SLAMBOX sensor
void odometry_callback(const nav_msgs::Odometry::ConstPtr &msg) {
  // Do something with odometry msg
 
  std::cout << "pos x: " << msg.pose.pose.position.x <<
               " pos y: " << msg.pose.pose.position.y <<
               " pos z: " << msg.pose.pose.position.z << std::endl;
}
 
void pointcloud_callback(const sensor_msgs::PointCloud2::ConstPtr &msg) {
  // Do somting with pointcloud msg here
  return;
}
 
int main(int argc, char** argv) {
  ros::init(argc, argv, "exampleSubscriber");
 
  ros::NodeHandle nh;
  odom_sub = nh.subscribe<nav_msgs::Odometry>("/SLAMBOX/odom", 200000, odometry_callback);
  pointcloud_sub = nh.subscribe<sensor_msgs::PointCloud2>("/SLAMBOX/pointcloud", 200000, pointcloud_callback);
 
  ros::spin();
  return 0;
}

5.2. Save PCD data

# CMD,SAVE_PCD,save_pcd_flag,reset_flag
$ rostopic pub /SLAMBOX/request std_msgs/String CMD,SAVE_PCD,1,0

• You can send the msg to SLAMBOX with code if you need

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