---
tags : DIT 2023寒假 -- ROS教學
---
{%hackmd BJrTq20hE %}

# rqt_reconfigure
> 動態調參工具

## 設置 cfg 檔
1. <font color="FF9900">在 package 底下生成 cfg 資料夾放置動態調參的設定</font>

$ roscd [PACKAGE_NAME]
$ mkdir cfg

2. <font color="FF9900">建立 cfg 檔，並放置想要動態調整的參數</font>

#!/usr/bin/env python3

# Import dynamic reconfigure tool
from dynamic_reconfigure.parameter_generator_catkin import *

# Set parameter generator
freq_params = ParameterGenerator()

# Add param "freq_pub"
# type : int
# range : 1 ~ 10
# original : 5
freq_params.add("freq_pub", int_t, 0, "Publish frequency", 5, 1, 10)

# Add param "data_pub"
# type : string
# original : "Nothing"
freq_params.add("data_pub", str_t, 0, "Publish data", "Nothing")

# [PACKAGE NAME] [NAMESPACE NAME] [GENERATE FILE NAME]
exit(freq_params.generate("reconf_test", "reconf_test", "dynamic_freq"))

3. <font color="FF9900">設置 CMakeList.txt</font>

## Find catkin macros and libraries
## if COMPONENTS list like find_package(catkin REQUIRED COMPONENTS xyz)
## is used, also find other catkin packages
find_package(catkin REQUIRED COMPONENTS
  dynamic_reconfigure # ADD this
  roscpp
  rospy
  std_msgs
)

## Generate dynamic reconfigure parameters in the 'cfg' folder
generate_dynamic_reconfigure_options(
  cfg/reconf_params.cfg
)

4. <font color="FF9900">設置 package.xml</font>

<build_depend>dynamic_reconfigure</build_depend>
<exec_depend>dynamic_reconfigure</exec_depend>

5. <font color="FF9900">catkin_make 以生成需要的標頭檔</font>

$ # In your top CMakeList.txt folder
$ catkin_make

## 設置監聽 server

#include <ros/ros.h>

#include <dynamic_reconfigure/server.h>
#include "reconf_test/dynamic_freqConfig.h"

int current_freq = 1;
std::string data = "HELLO";

void param_cb(reconf_test::dynamic_freqConfig &config, uint32_t level){
    current_freq = config.freq_pub;
    data = config.data_pub;
}

int main(int argc, char** argv){
    ros::init(argc, argv, "publisher_node");

    dynamic_reconfigure::Server<reconf_test::dynamic_freqConfig> param_srv;
    dynamic_reconfigure::Server<reconf_test::dynamic_freqConfig>::CallbackType callback;

    // If the function is a class member : 
    // boost::bind(&function, class instance, _1, _2)
    callback = boost::bind(&param_cb, _1, _2);

    // Set callback function to param server
    param_srv.setCallback(callback);

    while(ros::ok()){
        ros::Rate rate(current_freq);
        ROS_INFO_STREAM("Current : " << current_freq << "HZ, Data : " << data);
        ros::spinOnce();
        rate.sleep();
    }

}

- <font color="FF9900">在欲使用 dynamic parameter 的 node 上需額外增加 ```${PROJECT_NAME}_gencfg``` dependency</font>

add_dependencies(param_server ${${PROJECT_NAME}_EXPORTED_TARGETS} ${catkin_EXPORTED_TARGETS} ${PROJECT_NAME}_gencfg)

## 執行

1. <font color="FF9900">執行剛剛寫好的 param_server.cpp</font>

$ rosrun [PACKAGE NAME] [NAME_NAME]

2. <font color="FF9900">執行 rqt_reconfigure</font>

$ rqt -s rqt_reconfigure

3. <font color="FF9900">使用圖形界面調整參數，並觀察終端的輸出變化</font>

---