Teeterbot

A simulated two-wheeled inverted pendulum (self-balancing) robot for ROS 2 and Gazebo. Teeterbot is designed as a teaching platform for control systems, particularly balance control and motor control.

Overview

Teeterbot is a differential-drive robot that is inherently unstable — like a Segway, it will fall over without active control. Two variants are available:

• Standard teeterbot — no stability aids, requires a working balance controller
• Teeterbot with training wheels — adds passive support wheels so you can develop and test other behaviors (e.g., navigation) before implementing balance control

Launching the Simulator

Standard teeterbot (requires balance controller)

ros2 launch teeterbot_gazebo teeterbot.launch.xml

Teeterbot with training wheels

ros2 launch teeterbot_gazebo teeterbot_training_wheels.launch.xml

Including in your own launch file

To start the teeterbot simulator as part of your own launch file, use an <include> tag (XML launch files):

Standard teeterbot:

<?xml version="1.0"?>
<launch>

    <include file="$(find-pkg-share teeterbot_gazebo)/launch/teeterbot.launch.xml" />

    <!-- your nodes here -->

</launch>

Teeterbot with training wheels:

<?xml version="1.0"?>
<launch>

    <include file="$(find-pkg-share teeterbot_gazebo)/launch/teeterbot_training_wheels.launch.xml" />

    <!-- your nodes here -->

</launch>

ROS Topics

All topics are under the /teeterbot namespace.

Subscribed Topics (inputs — send commands here)

Topic	Type	Description
/teeterbot/left_speed_cmd	std_msgs/msg/Float64	Commanded left wheel speed (rad/s)
/teeterbot/right_speed_cmd	std_msgs/msg/Float64	Commanded right wheel speed (rad/s)
/teeterbot/left_torque_cmd	std_msgs/msg/Float64	Commanded left wheel torque (N·m)
/teeterbot/right_torque_cmd	std_msgs/msg/Float64	Commanded right wheel torque (N·m)

Speed vs. torque commands: You can command the wheels in either speed mode or torque mode. If both types of commands are sent, whichever has the more recent timestamp takes effect.

Published Topics (outputs — read sensor data here)

Topic	Type	Description
/teeterbot/imu	sensor_msgs/msg/Imu	IMU data: linear acceleration, angular velocity, orientation
/teeterbot/left_speed	std_msgs/msg/Float64	Measured left wheel speed (rad/s)
/teeterbot/right_speed	std_msgs/msg/Float64	Measured right wheel speed (rad/s)
/teeterbot/fallen_over	std_msgs/msg/Bool	true when the robot has tipped past 60° from vertical
/clock	rosgraph_msgs/msg/Clock	Simulation clock (use with use_sim_time:=true)

Wheel speeds and the fallen-over flag are published at 100 Hz. The IMU publishes at 100 Hz.

When /teeterbot/fallen_over becomes true, the motor controllers are reset and stop applying torque. The robot must be reset in Gazebo to continue.

Package Structure

Package	Description
teeterbot	Metapackage
teeterbot_description	SDF robot model files
teeterbot_gazebo	Gazebo plugin, launch files, and world files