平台：Ubuntu18.04 ROS melodic ros_serial工具包

目的：采用ros工具包实现串口通信与解析

下载依赖

利用ros工具包实现串口通信与解析

  • 常用的ch340驱动安装已经在之前的文章讲过了，有需要可以自行查找

  • 由于国内网络问题，ros的下载可能需要用到魔法上网或者其他方法，以后会单开一篇说明

  • 下载串口工具包

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sudo apt-get install ros-melodic-serial

下载完成后重启shell，输入以下命令来测试

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roscd serial

新建工程

  • 利用catkin工具包生成相关工程

  • 首先生成工作环境

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mkdir -p ~/catkin_ws/src
cd ~/catkin_ws/src/
catkin_init_workspace
cd ~/catkin_ws/
catkin_make
echo "source ~/catkin_ws/devel/setup.bash">>~/.bashrc
source ~/.bashrc 
echo $ROS_PACKAGE_PATH
  • 添加ros工具包
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cd ~/catkin_ws/src/
catkin_create_pkg serial_port roscpp rospy std_msgs serial

  • 以上工具包依次为ros对于c++语言和python语言包的支持以及message传输包和串口包

  • 按照程序组成依次生成以下文件

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serial_port
├── CMakeLists.txt
├── include
│   └── serial_port
│       ├── serialport.hpp 
│       ├── serialpost.hpp #节点通信测试，可忽略
│       └── serialread.hpp
├── package.xml
└── src
    ├── answer.cpp #节点通信测试，可忽略
    ├── serialport.cpp 
    ├── serialpost.cpp #节点通信测试，可忽略
    └── serialread.cpp
  • 实现串口收发主程序c++代码源文件serialport.cpp
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#include "serialport.hpp"

//main body
int main(int argc, char** argv)
{
    ros::init(argc, argv, "serial_port_basic");
    //create a nodehandle
    ros::NodeHandle n;    
    //create a serial class
    serial::Serial sp;
    //create the timeout warning
    serial::Timeout to = serial::Timeout::simpleTimeout(10);
    //edit the port (for the first serial port the ch340 connected is ttyUSB0)
    sp.setPort("/dev/ttyUSB0");
    //set baudrate
    sp.setBaudrate(115200);
    //set seial timeout
    sp.setTimeout(to); 

    try{
        //open port
        sp.open();
    }
    catch(serial::IOException& e){
        ROS_ERROR_STREAM("Unable to open port.");
        return -1;
    }

    if(sp.isOpen()){
        ROS_INFO_STREAM("serial is opened.");
    }else{
        return -1;
    }

    //control the rate of loop
    ros::Rate loop_rate(100);

    //use for test    
    uint8_t buffer_test[6]={0xAE,0xAA,0x11,0x22,0x22,0XFF};
    sp.write(buffer_test, 6);

    while(ros::ok())
    {   //open the subscriber for once 
        ros::spinOnce();
        //read from linux buffer
        size_t n = sp.available();
        if(n!=0)
        {
            //the lagest buffer place is 64 x hex 
            uint8_t buffer[64];
            //put the data into buffer
            n = sp.read(buffer, n);
             // printf for  test
            //  for(int i=0; i<n; i++){
            //  printf("the origin buffer is %x",buffer[i]) ;
            //  }
            //     std::cout << std::endl;
             int err =  buffer_read(buffer);
             //write back for test
             sp.write(buffer, n);
        }
        //wait for the next turn
        loop_rate.sleep();
    }
    //close the port
    sp.close();
    return 0;
}

serialport对应的c++头文件

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#ifndef  __PORT_H__
#define __PORT_H__

#include <ros/ros.h>
#include <serial/serial.h>
#include <iostream>
#include<stdio.h>
#include "serialread.hpp"
#include "serialpost.hpp"

#endif
  • 对于读入数据简单解析serialread.cpp(可拓展)
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#include "serialread.hpp"

int buffer_read(uint8_t *buffer){
    int max_size=64;
    int status=0;
    //the head of the serial port is 0xAE
    if(buffer[0]==0xAE){
        status=1;
    }else {
        return 0;
    }
   //choose the mod of the receiving data
   switch(buffer[1]){
        case 0xAA:
            status=2;
            break;
        default:
            return 0;
            break;
   }
   //the fuction that write for an example
    if(status==2){
        if(buffer[5]==0xFF){
            printf("roll=%d,yaw=%d,pitch=%d\n",buffer[2],buffer[3],buffer[4]);
        }else{
            return 0;
        }
    }else{
        return 0;
    }
    //report error
    return status;

}
  • 对应的头文件
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#ifndef  __READ_H__
#define __READ_H__

#include <ros/ros.h>
#include <serial/serial.h>
#include <iostream>
#include<stdio.h>
#include "serialread.hpp"
#include "serialpost.hpp"

 //the example write to analyse the hex code
int buffer_read(uint8_t *buffer);

//crc
//

#endif
  • 注意修改cmake文件，在文件结尾加上
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add_executable(serial_port  src/serialport.cpp 
                          src/serialpost.cpp src/serialread.cpp)  
target_link_libraries(serial_port  ${catkin_LIBRARIES})
add_executable(answer src/answer.cpp)  
target_link_libraries(answer ${catkin_LIBRARIES})
  • 利用catkin编译
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cd ~/catkin_ws
catkin_make
. ~/catkin_ws/devel/setup.bash
rosrun serial_port serial_port
  • 可以看到数据像疯狗一样涌来