MAVLink入门教程09.03：通过UDP发送数据至QGC

系列索引：MAVLink入门教程索引

目的

本文介绍如何通过UDP直接发送数据给QGC的Mavlink框架中。

MavSDK

先从MAVSDK下载静态库。

只能使用VS2022编译运行

心跳包

MavSDK初始化

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auto component_type = Mavsdk::ComponentType::Autopilot;//1
auto config = Mavsdk::Configuration(component_type);//2
auto mav = Mavsdk(config);//3
std::cout << "Mavsdk version: " << mav.version() << std::endl;
std::cout << "Sys ID: " << unsigned(config.get_system_id())  // use unsigned for uin8_t
    << ", Component ID: " << unsigned(config.get_component_id())
    << ", Always heartbeats: " << config.get_always_send_heartbeats()
    << std::endl;

Mavsdk定义了一个Mavsdk类，需要先将这个类实例化后再使用。

主要语句就是这个第3行。config是Configuration类的一个实例，对应第一行代码。Autopilot是mavsdk中已经定义好的枚举类型，也可以指定其他类型。

运行输出为

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[05:02:30|Info ] MAVSDK version: v2.10.0 (D:\a\MAVSDK\MAVSDK\src\mavsdk\core\mavsdk_impl.cpp:26)
Mavsdk version: v2.10.0
Sys ID: 1, Component ID: 1, Always heartbeats: 1

UDP

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// Use my own udp library
auto udp = UdpCom();
int r = udp.Open("127.0.0.1", 14540, "127.0.0.1", 14550);
std::cout << "UDP Open: " << r << std::endl;

打开本地的14540/14550端口，这个是QGC/Mavlink默认端口

心跳包

根据流程创建心跳包并填充数据

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// Heartbeat message
mavlink_message_t msg_heartbeat;
uint8_t len_heartbeat;
uint8_t buf_heartbeat[MAVLINK_MAX_PACKET_LEN];
mavlink_msg_heartbeat_pack(config.get_system_id(), config.get_component_id(), &msg_heartbeat,
    MAV_TYPE_QUADROTOR, MAV_AUTOPILOT_GENERIC, MAV_MODE_GUIDED_ARMED, 0, MAV_STATE_ACTIVE);
len_heartbeat = mavlink_msg_to_send_buffer(buf_heartbeat, &msg_heartbeat);

无论是串口还是udp，最后发送的都是字节码buf_heartbeat而不是msg_heartbeat结构体。

发送

以1Hz的频率发送

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// Whenever a second has passed, we send a message.
while (true)
{
    current_time = time(NULL);
    if (current_time - last_time >= 1) {
        udp.Send((char*)(buf_heartbeat), len_heartbeat);
        std::cout << "Heartbeat sent." << std::endl;

        last_time = current_time;
    }
}

效果

编译运行程序。

打开QGC

QGC

先打开数据发送程序，后打开QGC，此时QGC是连接状态

点击左上角打开工具

工具

选择应用设置

应用设置

点击MAVLink Inspector标签，自动显示接收的数据

MAVLink Inspector

频率为1Hz，数据类型，数据值都有显示。

Vibration（震动）

根据心跳包的创建流程创建震动数据包

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// Vibration message
mavlink_message_t msg_vibration;
uint8_t len_vibration;
uint8_t buf_vibration[MAVLINK_MAX_PACKET_LEN];
uint64_t time_usec=1000;
float vx = 25;
float vy = 50;
float vz = 100;
uint32_t c0=1;
uint32_t c1=2;
uint32_t c2=3;
mavlink_msg_vibration_pack(config.get_system_id(), config.get_component_id(), &msg_vibration, 
    time_usec, vx, vy, vz, c0, c1, c2);
len_vibration = mavlink_msg_to_send_buffer(buf_vibration, &msg_vibration);

通过UDP发送数据。

查看Analyze Tools -> Vibration界面

震动

数据开始发送后

接收数据

完整代码

库文件

此部分是VS工程设置

VS编译设置为C++17标准

C++17标准

头文件

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$(SolutionDir)mavsdk\include;

库文件

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$(SolutionDir)/mavsdk/lib;
ws2_32.lib;mavsdk.lib;

UDP

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/*****************************************************************
 * @file   samll_udp.h
 * @brief  A very simple header-only library for udp communication in Windows.
 *
 * @author zswzy
 * @date   20230529
 *********************************************************************/

#ifndef SUDP_HPP
#define SUDP_HPP

#include <stdio.h>
#include <string>
#include <WS2tcpip.h>

#pragma comment (lib, "ws2_32.lib")

class UdpCom {
private:
    SOCKET			m_in;
    sockaddr_in		m_local;
    const char*		m_local_ip;
    int				m_local_port;
    int				m_local_length;
    sockaddr_in		m_dest;
    const char*		m_dest_ip;
    int				m_dest_port;
    int				m_dest_length;
    char			m_buffer[4096];
public:
    /**
     * @brief The UDP class constructor.
     *
     * @return
     */
    UdpCom()
    {
        m_in			= NULL;
        m_local			= sockaddr_in();
        m_local_length  = sizeof(m_local);
        m_local_ip		= "127.0.0.1";
        m_local_port	= 0;
        m_dest			= sockaddr_in();
        m_dest_length	= sizeof(m_dest);
        m_dest_ip		= "0.0.0.0";
        m_dest_port		= 0;
        memset(m_buffer, 0, sizeof(m_buffer));
        ZeroMemory(&m_dest, sizeof(m_dest));
    }

    /**
     * @brief destructor.
     *
     */
    ~UdpCom()
    {Close();}

    /**
     * @brief Open UDP.
     * @return 0: normal, 1: Winsock error, 2: bind error.
     */
    int Open()
    {
        int return_code = 0;
        // Startup Winsock 开启winsock
        WSADATA data;
        WORD version = MAKEWORD(2, 2);
        int wsOK = WSAStartup(version, &data);
        if (wsOK != 0) {
            printf("can't start Winsock. Error: %d.\n", wsOK);
            return_code = 1;
        }
        // Bind socket 绑定本地端口号
        m_in = socket(AF_INET, SOCK_DGRAM, 0);
        m_local.sin_family = AF_INET;
        m_local.sin_port = htons(m_local_port); // Convert from little to big endian
        inet_pton(AF_INET, m_local_ip, &m_local.sin_addr);
        // 检测是否成功绑定
        if (bind(m_in, (sockaddr*)&m_local, sizeof(m_local)) == SOCKET_ERROR)
        {
            printf("Can't bind socket! Error: %d.\n", WSAGetLastError());
            return_code = 2;
        }
        // 绑定远端
        m_dest.sin_family = AF_INET;
        inet_pton(AF_INET, m_dest_ip, &m_dest.sin_addr);
        m_dest.sin_port = htons(m_dest_port);
        printf("UDP is open.\n");
        return return_code;
    }

    /**
     * @brief Open UDP with parameters.
     *
     * @param local_ip		local IPv4 address.
     * @param local_port	local port.
     * @param dest_ip		remote IPv4 address.
     * @param dest_port		remote port.
     * @return
     */
    int Open(const char* local_ip, const int local_port, const char* dest_ip, const int dest_port)
    {
        SetLocal(local_ip, local_port);
        SetDest(dest_ip, dest_port);
        Open();
        return 0;
    }

    /**
     * @brief Receive message from remote.
     *
     * @return
     */
    int Receive()
    {
        ZeroMemory(m_buffer, 4096);
        // 接收消息，储存为变量buf，类型为字符串
        int byte_in = recvfrom(m_in, m_buffer, 4096, 0, (sockaddr*)&m_dest, &m_dest_length);

        if (byte_in == SOCKET_ERROR)
        {
            printf("Error receiving from client. Error code: %d", WSAGetLastError());
        }
        printf("%s \n",m_buffer);
        //recv_data = jsonxx::json::parse(m_buffer);
        return 0;
    }

    /**
     * @brief Send message to remote.
     *
     * @param message_send
     * @return 0: normal, 1: Error.
     */
    int Send(char* message_send, int len)
    {
        int return_code = 0;
        //printf("message_send: %s, sizeof: %d\n", message_send, strlen(message_send));
        int send_ok = sendto(m_in, message_send, len, 0, (sockaddr*)&m_dest, sizeof(m_dest));
        if (send_ok == SOCKET_ERROR)
        {
            printf("Send error.\n");
            return_code = 1;
        }
        else
        {
            // std::cout << "Send OK" << std::endl;
        }

        return return_code;
    }

    /**
     * @brief Close UDP. It is called in the destructor.
     *
     * @return
     */
    int Close()
    {
        // Close socket
        closesocket(m_in);
        // Shutdown winsock
        WSACleanup();
        return 0;
    }

    /**
     * @brief Set remote parameters: IP and port.
     *
     * @param dest_ip	remote IPv4 address.
     * @param dest_port remote port.
     * @return
     */
    int SetDest(const char* dest_ip, const int dest_port)
    {
        m_dest_ip = dest_ip;
        m_dest_port = dest_port;
        return 0;
    }

    /**
     * @brief Set local parameters: IP and port.
     *
     * @param local_ip		local IPv4 address.
     * @param local_port	local port
     * @return
     */
    int SetLocal(const char* local_ip, const int local_port)
    {
        m_local_ip = local_ip;
        m_local_port = local_port;
        return 0;
    }

    /**
     * @brief Get received message.
     *
     * @return
     */
    char* GetContent()
    {
        return m_buffer;
    }
};

#endif // SUDP_HPP

main

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// System
#include <iostream>
#include <time.h>

// Project header
#include "sudp.hpp"

// MAVSDK
#include "mavsdk/mavsdk.h"

using namespace mavsdk;

int main()
{
    auto component_type = Mavsdk::ComponentType::Autopilot;
    auto config = Mavsdk::Configuration(component_type);
    auto mav = Mavsdk(config);
    std::cout << "Mavsdk version: " << mav.version() << std::endl;
    std::cout << "Sys ID: " << unsigned(config.get_system_id())  // use unsigned for uin8_t
        << ", Component ID: " << unsigned(config.get_component_id())
        << ", Always heartbeats: " << config.get_always_send_heartbeats()
        << std::endl;

    // Use my own udp library
    auto udp = UdpCom();
    int r = udp.Open("127.0.0.1", 14540, "127.0.0.1", 14550);
    std::cout << "UDP Open: " << r << std::endl;

    // Timing
    static time_t last_time = 0;
    time_t start_time = time(NULL);
    time_t current_time = time(NULL);

    // Heartbeat message
    mavlink_message_t msg_heartbeat;
    uint8_t len_heartbeat;
    uint8_t buf_heartbeat[MAVLINK_MAX_PACKET_LEN];
    mavlink_msg_heartbeat_pack(config.get_system_id(), config.get_component_id(), &msg_heartbeat,
        MAV_TYPE_QUADROTOR, MAV_AUTOPILOT_GENERIC, MAV_MODE_GUIDED_ARMED, 0, MAV_STATE_ACTIVE);
    len_heartbeat = mavlink_msg_to_send_buffer(buf_heartbeat, &msg_heartbeat);

    // Vibration message
    mavlink_message_t msg_vibration;
    uint8_t len_vibration;
    uint8_t buf_vibration[MAVLINK_MAX_PACKET_LEN];
    uint64_t time_usec=1000;
    float vx = 25;
    float vy = 50;
    float vz = 100;
    uint32_t c0=1;
    uint32_t c1=2;
    uint32_t c2=3;
    mavlink_msg_vibration_pack(config.get_system_id(), config.get_component_id(), &msg_vibration, 
        time_usec, vx, vy, vz, c0, c1, c2);
    len_vibration = mavlink_msg_to_send_buffer(buf_vibration, &msg_vibration);

    // Whenever a second has passed, we send a message.
    while (true)
    {
        current_time = time(NULL);
        if (current_time - last_time >= 1) {
            udp.Send((char*)(buf_heartbeat), len_heartbeat);
            std::cout << "Heartbeat sent." << std::endl;

            udp.Send((char*)(buf_vibration), len_vibration);
            std::cout << "Vibration sent." << std::endl;

            last_time = current_time;
        }
    }

    return 0;
}
MAVLink
#UDP #QGC #MAVLink #QGroundControl #通信
MAVLink入门教程09.03：通过UDP发送数据至QGC
https://blog.jackeylea.com/mavlink/send-data-to-qgc-with-udp/
作者
JackeyLea
发布于
2024年6月15日
许可协议