SLAM Initialization Commands for TurtleBot3

Overview
#

SLAM (Simultaneous Localization and Mapping) allows a robot to build a map while tracking its position. This guide covers the initialization commands for TurtleBot3.

System Architecture
#

┌─────────────────────────────────┐
│              PC                  │
│  ┌─────────┐  ┌──────────────┐  │
│  │ roscore │  │ SLAM + RViz  │  │
│  └────┬────┘  └──────┬───────┘  │
│       │              │          │
└───────┼──────────────┼──────────┘
        │    WiFi      │
┌───────┼──────────────┼──────────┐
│       │              │          │
│  ┌────┴────────┐     │          │
│  │  Bringup   │     │          │
│  │ (sensors)  │←────┘          │
│  └────────────┘                 │
│         TurtleBot3              │
└─────────────────────────────────┘

Step 1: Start ROS Master (PC)
#

roscore

Expected output:

... logging to /home/user/.ros/log/...
started roslaunch server http://192.168.0.3:xxxxx/
ros_comm version 1.16.0

SUMMARY
========

PARAMETERS
 * /rosdistro: noetic
 * /rosversion: 1.16.0

NODES

auto-starting new master
process[master]: started with pid [xxxx]
ROS_MASTER_URI=http://192.168.0.3:11311
...

Step 2: Launch Robot (TurtleBot3)
#

SSH into TurtleBot3:

ssh ubuntu@<TURTLEBOT_IP>

Set model and launch:

export TURTLEBOT3_MODEL=burger
roslaunch turtlebot3_bringup turtlebot3_robot.launch

Expected output:

SUMMARY
========

PARAMETERS
...

NODES
  /
    turtlebot3_core (rosserial_python/serial_node.py)
    turtlebot3_diagnostics (turtlebot3_bringup/turtlebot3_diagnostics)
    turtlebot3_lds (hls_lfcd_lds_driver/hlds_laser_publisher)

...
[INFO] Calibration End

Key nodes:

turtlebot3_core: Serial communication with OpenCR
turtlebot3_lds: Laser scanner driver
turtlebot3_diagnostics: System health monitoring

Step 3: Launch SLAM (PC)
#

export TURTLEBOT3_MODEL=burger
roslaunch turtlebot3_slam turtlebot3_slam.launch

This launches:

SLAM algorithm (gmapping by default)
RViz for visualization

Alternative SLAM Methods
#

# Gmapping (default)
roslaunch turtlebot3_slam turtlebot3_slam.launch slam_methods:=gmapping

# Cartographer
roslaunch turtlebot3_slam turtlebot3_slam.launch slam_methods:=cartographer

# Hector SLAM
roslaunch turtlebot3_slam turtlebot3_slam.launch slam_methods:=hector

Step 4: Launch Teleop (PC)
#

In a new terminal:

export TURTLEBOT3_MODEL=burger
roslaunch turtlebot3_teleop turtlebot3_teleop_key.launch

Control keys:

        w
   a    s    d
        x

w/x: Increase/decrease linear velocity
a/d: Increase/decrease angular velocity
s: Stop
CTRL+C: Quit

Verification
#

Check Topics
#

rostopic list

Important topics:

/scan: Laser data
/odom: Odometry
/map: Generated map
/cmd_vel: Velocity commands

Monitor Laser
#

rostopic echo /scan

View TF Tree
#

rosrun rqt_tf_tree rqt_tf_tree

Saving the Map
#

After exploring:

rosrun map_server map_saver -f ~/map

Creates:

map.pgm: Image file
map.yaml: Metadata

Troubleshooting
#

Issue	Solution
No laser data	Check LDS connection
Robot not moving	Verify OpenCR power
Map drifting	Move slower, better loop closure
RViz not showing	Check Fixed Frame = “map”

Complete Command Summary
#

Terminal	Machine	Command
1	PC	`roscore`
2	TB3 (SSH)	`roslaunch turtlebot3_bringup turtlebot3_robot.launch`
3	PC	`roslaunch turtlebot3_slam turtlebot3_slam.launch`
4	PC	`roslaunch turtlebot3_teleop turtlebot3_teleop_key.launch`

Overview#

System Architecture#

Step 1: Start ROS Master (PC)#

Step 2: Launch Robot (TurtleBot3)#

Step 3: Launch SLAM (PC)#

Alternative SLAM Methods#

Step 4: Launch Teleop (PC)#

Verification#

Check Topics#

Monitor Laser#

View TF Tree#

Saving the Map#

Troubleshooting#

Complete Command Summary#