Rover Kinematics Node

ROS2 package for 6-wheel differential drive rover kinematics.

Overview

This node subscribes to /cmd_vel (geometry_msgs/Twist) and converts linear.x and angular.z velocities into individual wheel RPMs for a 6-wheel differential drive rover. The RPMs are published as a Float32MultiArray to /teensy_motor_rpms.

Package Structure

src/kinematics_node/
├── kinematics_node/
│   ├── __init__.py
│   └── rover_kinematics_node.py
├── config/
│   └── rover_kinematics.yaml
├── launch/
│   └── rover_kinematics.launch.py
├── resource/
│   └── kinematics_node
├── package.xml
├── setup.py
└── setup.cfg

Building

cd <workspace_root>
colcon build --packages-select kinematics_node
source install/setup.bash

Running

# With default parameters
ros2 run kinematics_node rover_kinematics_node

# With launch file (loads config)
ros2 launch kinematics_node rover_kinematics.launch.py

Parameters

• wheel_base: Distance between left and right wheels (m)
• wheel_diameter: Wheel diameter (m)
• max_linear_speed: Maximum linear velocity (m/s)
• max_angular_speed: Maximum angular velocity (rad/s)
• linear_usage: Fraction of max linear speed to use (0-1)
• angular_usage: Fraction of max angular speed to use (0-1)
• max_rpm: Maximum RPM clamp
• cmd_vel_timeout: Safety timeout for cmd_vel (s)
• input_cmd_topic: Input topic name (default: /cmd_vel)
• output_topic: Output topic name (default: /teensy_motor_rpms)
• update_rate: Publishing rate (Hz)

Topics

Subscribed

• /cmd_vel (geometry_msgs/Twist): Velocity commands

Published

• /teensy_motor_rpms (std_msgs/Float32MultiArray): 6 wheel RPMs [left0, right1, left2, right3, left4, right5]

Wheel Mapping

• Wheels 0, 2, 4: Left side
• Wheels 1, 3, 5: Right side