Robot Development at the Forefront: Transforming the future of system building with "ROS2"

// my_node.hpp -------------------------------------------------------------

// ROS2 library inclusions
#include "rclcpp/rclcpp.hpp“

// Message type inclusions
// Standard ROS2 message types as well as custom message types can be used
#include “std_msgs/msg/float32.hpp" // Standard ROS2 message type
#include “my_msgs/msg/route.hpp" // Custom message type

// Define a unique node by inheriting the Node class
class MyNode : public rclcpp::Node
{
public:
MyNode(const rclcpp::NodeOptions& options = rclcpp::NodeOptions());
private:
// Subscriber definition
rclcpp::Subscription<my_msgs::msg::Route>::SharedPtr _sub;
// Publisher definition
rclcpp::Publisher<std_msgs::msg::Float32>::SharedPtr _pub;
// Callback function definition
void _callback(const my_msgs::msg::Route::SharedPtr msg);
};

// my_node.cpp -------------------------------------------------------------

#include “my_node.hpp“

// The constructor sets up the publisher and subscriber.
// Communication is configured in just a few lines of code.
MyNode::MyNode(const rclcpp::NodeOptions& options):
rclcpp::Node(“my_node", options)
{
// Subscriber setup
_sub = this->create_subscription<my_msgs::msg::Route>(
“target_route",
rclcpp::QoS(10),
std::bind(&myNode::_callback, this, std::placeholders::_1)
);
// Publisher setup
_pub = this->create_publisher<std_msgs::msg::Float32>(
“target_velocity”,
rclcpp::QoS(10),
);
}

// The callback function: This is the main processing loop of the node.
void MyNode::_callback(const my_msgs::msg::Route::SharedPtr msg)
{
// Main processing logic, such as calculating the target velocity for a robot's travel control.
float target_velocity = calculate_target_velocity(msg);
// Convert the calculation result into a message.
auto pub_msg = std_msgs::msg::Float32();
pub_msg.data = target_velocity;
// Publish the message.
_pub->publish(pub_msg);
}

// main.cpp -------------------------------------------------------------

// main function: Initializes ROS2 and executes the node.
int main(int argc, char * argv[]) {
// ROS2 initialization
rclcpp::init(argc, argv);

// Node execution
rclcpp::spin(std::make_shared<MyNode>());

// ROS2 shutdown
rclcpp::shutdown();
return 0;
}