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本教程介绍了ROS中的参数服务，以及如何通过C++代码的形式获取，设置参数。至于为什么选择deepin而不是ROS通用的ubuntu,也仅仅是为了支持国产系统。鉴于本人水平有限，如哪位攻城狮网友发现本文存在的问题，烦请留言指正，谢谢!

参数的使用与编程

Parameter Server

ROS master中有Parameter server用于存储其他节点的配置参数的全局字典

创建parameter包

catkin_create_pkg learn_parameter roscpp std_srvs

rosparam相关命令行的使用

可用tab进行参数补全

• rosparam list ：列出当前的参数
• rosparam get param_key:获取某个参数的值
• rosparam set param_key param_value:设置某个参数的值
• rosparam dump file_name:将参数保存到文件中
• rosparam load file_name:从文件读取参数
• rosparam delete param_key:删除参数

gaoy@msi:~$ rosparam list
/rosdistro
/roslaunch/uris/host_msi__38003
/rosversion
/run_id
/turtlesim/background_b
/turtlesim/background_g
/turtlesim/background_r
gaoy@msi:~$ rosparam get /rosversion 
'1.15.14

  '

gaoy@msi:~$ rosparam get /rosdistro 
gaoy@msi:~$ 
gaoy@msi:~$ rosparam list
/rosdistro
/roslaunch/uris/host_msi__38003
/rosversion
/run_id
/turtlesim/background_b
/turtlesim/background_g
/turtlesim/background_r
gaoy@msi:~$ rosparam get /turtlesim/background_b 
255
gaoy@msi:~$ rosparam set /turtlesim/background_b  120
gaoy@msi:~$ rosparam get /turtlesim/background_b 
120
gaoy@msi:~$ rosparam get /rosdistro 
'noetic

  '

# 下面命令使用后/turtlesim/background_x的参数会生效 用于刷新小乌龟仿真器的背景颜色
gaoy@msi:~$ rosservice call /clear "{}"

# 存储当前环境的参数
gaoy@msi:~$ rosparam dump p.yam
gaoy@msi:~$ cat p.yam 
rosdistro: 'noetic

  '
roslaunch:
  uris: {host_msi__38003: 'http://msi:38003/'}
rosversion: '1.15.14

  '
run_id: 58532efc-3695-11ed-a033-f8b54d546b81
turtlesim: {background_b: 120, background_g: 86, background_r: 69}

配置参数基本使用YAML文件形式进行存储

rosdistro: 'noetic

  '
roslaunch:
  uris: {host_msi__38003: 'http://msi:38003/'}
rosversion: '1.15.14

  '
run_id: 58532efc-3695-11ed-a033-f8b54d546b81
turtlesim: {background_b: 0, background_g: 0, background_r: 69}
  '

测试源码

#include <string>
#include "ros/ros.h"
#include "std_srvs/Empty.h"

int main(int argc,char ** argv){

    int bkg_color_g;
    ros::init(argc,argv,"param_config");
    ros::NodeHandle n;

    ros::param::get("/turtlesim/background_g",bkg_color_g);
    ROS_INFO("Get /turtlesim/background_g:%d\n",bkg_color_g);
    // ros::param::get("/rosdistro",a);

    ros::param::set("/turtlesim/background_g",255);
    ros::param::get("/turtlesim/background_g",bkg_color_g);
    ROS_INFO("Get /turtlesim/background_g:%d\n",bkg_color_g);
    
    ros::service::waitForService("/clear");

    ros::ServiceClient cbc = n.serviceClient<std_srvs::Empty>("/clear");
    std_srvs::Empty srv;
    cbc.call(srv);
    return 0;
    
}