ROS2发布LaserScan消息

?一、消息结构：

# Single scan from a planar laser range-finder
#
# If you have another ranging device with different behavior (e.g. a sonar
# array), please find or create a different message, since applications
# will make fairly laser-specific assumptions about this data

std_msgs/Header header # timestamp in the header is the acquisition time of
                             # the first ray in the scan.
                             #
                             # in frame frame_id, angles are measured around
                             # the positive Z axis (counterclockwise, if Z is up)
                             # with zero angle being forward along the x axis

float32 angle_min            # start angle of the scan [rad]
float32 angle_max            # end angle of the scan [rad]
float32 angle_increment      # angular distance between measurements [rad]

float32 time_increment       # time between measurements [seconds] - if your scanner
                             # is moving, this will be used in interpolating position
                             # of 3d points
float32 scan_time            # time between scans [seconds]

float32 range_min            # minimum range value [m]
float32 range_max            # maximum range value [m]

float32[] ranges             # range data [m]
                             # (Note: values < range_min or > range_max should be discarded)
float32[] intensities        # intensity data [device-specific units].  If your
                             # device does not provide intensities, please leave
                             # the array empty.

二、Python程序

import rclpy
from rclpy.node import Node
from sensor_msgs.msg import LaserScan

class LaserScanPublisher(Node):
    def __init__(self):
        super().__init__('laser_scan_publisher')
        self.publisher_ = self.create_publisher(LaserScan, 'laser_scan', 10)
        self.timer_ = self.create_timer(1.0, self.publish_scan)

    def publish_scan(self):
        scan_msg = LaserScan()
        # 设置LaserScan消息的各个字段
        scan_msg.header.frame_id = 'laser_frame'
        scan_msg.header.stamp = self.get_clock().now().to_msg()
        scan_msg.angle_min = -1.57
        scan_msg.angle_max = 1.57
        scan_msg.angle_increment = 0.01
        scan_msg.time_increment = 0.0
        scan_msg.scan_time = 0.1
        scan_msg.range_min = 0.0
        scan_msg.range_max = 10.0
        scan_msg.ranges = [1.0, 2.0, 3.0, 4.0, 5.0]
        scan_msg.intensities = [100, 200, 300, 400, 500]

        self.publisher_.publish(scan_msg)

def main(args=None):
    rclpy.init(args=args)
    laser_scan_publisher = LaserScanPublisher()
    rclpy.spin(laser_scan_publisher)
    laser_scan_publisher.destroy_node()
    rclpy.shutdown()

if __name__ == '__main__':
    main()

三、C++程序

#include "rclcpp/rclcpp.hpp"
#include "sensor_msgs/msg/laser_scan.hpp"

using std::placeholders::_1;

class LaserScanPublisher : public rclcpp::Node
{
public:
  LaserScanPublisher()
  : Node("laser_scan_publisher")
  {
    publisher_ = this->create_publisher<sensor_msgs::msg::LaserScan>("laser_scan", 10);
    timer_ = this->create_wall_timer(std::chrono::milliseconds(1000), std::bind(&LaserScanPublisher::publish_scan, this));
  }

private:
  void publish_scan()
  {
    auto scan_msg = std::make_shared<sensor_msgs::msg::LaserScan>();
    // 设置LaserScan消息的各个字段
    scan_msg->header.frame_id = "laser_frame";
    scan_msg->header.stamp = this->now();
    scan_msg->angle_min = -1.57;
    scan_msg->angle_max = 1.57;
    scan_msg->angle_increment = 0.01;
    scan_msg->time_increment = 0.0;
    scan_msg->scan_time = 0.1;
    scan_msg->range_min = 0.0;
    scan_msg->range_max = 10.0;
    scan_msg->ranges = {1.0, 2.0, 3.0, 4.0, 5.0};
    scan_msg->intensities = {100, 200, 300, 400, 500};

    publisher_->publish(*scan_msg);
  }

  rclcpp::Publisher<sensor_msgs::msg::LaserScan>::SharedPtr publisher_;
  rclcpp::TimerBase::SharedPtr timer_;
};

int main(int argc, char * argv[])
{
  rclcpp::init(argc, argv);
  auto laser_scan_publisher = std::make_shared<LaserScanPublisher>();
  rclcpp::spin(laser_scan_publisher);
  rclcpp::shutdown();
  return 0;
}