关于ROS下的Dynamic Reconfig的学习探索

Dynamic Reconfig是ROS比较厉害的一个地方，可以在程序运行的时候动态调整参数，ROS官网关于Dynamic Reconfig的讲解主要有三处

1. http://wiki.ros.org/dynamic_reconfigure/Tutorials

2. http://wiki.ros.org/roscpp_tutorials/Tutorials 最下面

3. http://wiki.ros.org/ROSNodeTutorialC++ 最下面

个人感觉第一个好一点，另外两个比较杂乱。下面就介绍自己关于Dynamic Reconfig学习过程，这里假定大家都做完了，Beginner tutorials的学习，即写一个Publisher ，subscriber，自定义的service（两个数字的加法）以及Msg的学习。

主要参考：

http://wiki.ros.org/dynamic_reconfigure/Tutorials/SettingUpDynamicReconfigureForANode

我的最终的文件目录如图

1.定义cfg文件

首先在catkin_ws/src/beginner_tutorials目录下建立一个名为cfg的文件夹，放入一个名为MyStuff.cfg的文件，这个文件的作用就是告诉ROS 到时侯我们需要动态调整的参数有哪些。

#! /usr/bin/env python # Forearm camera configurationPACKAGE='beginner_tutorials'import roslibroslib.load_manifest(PACKAGE)from math import pifrom driver_base.msg import SensorLevelsfrom dynamic_reconfigure.parameter_generator import *gen = ParameterGenerator()angles = gen.add_group("Angles")#       Name                    Type      Reconfiguration level#       Description#       Default  Min  Maxangles.add("min_ang",           double_t, SensorLevels.RECONFIGURE_STOP,           "The angle of the first range measurement. The unit depends on ~ang_radians.",           -pi/2,-pi, pi)angles.add("max_ang",           double_t, SensorLevels.RECONFIGURE_STOP,           "The angle of the first range measurement. The unit depends on ~ang_radians.",            pi/2, -pi, pi)gen.add("intensity",            bool_t,   SensorLevels.RECONFIGURE_STOP,        "Whether or not the hokuyo returns intensity values.",         False)gen.add("cluster",              int_t,    SensorLevels.RECONFIGURE_STOP,        "The number of adjacent range measurements to cluster into a single reading",         1, 0, 99)gen.add("skip",                 int_t,    SensorLevels.RECONFIGURE_STOP,        "The number of scans to skip between each measured scan",         0, 0,  9)gen.add("port",                 str_t,    SensorLevels.RECONFIGURE_CLOSE,        "The serial port where the hokuyo device can be found",        "/dev/ttyACM0")gen.add("calibrate_time",       bool_t,   SensorLevels.RECONFIGURE_CLOSE,        "Whether the node should calibrate the hokuyo's time offset",         True)gen.add("frame_id",             str_t,    SensorLevels.RECONFIGURE_RUNNING,        "The frame in which laser scans will be returned",        "laser")gen.add("time_offset",          double_t, SensorLevels.RECONFIGURE_RUNNING,        "An offet to add to the timestamp before publication of a scan",         0, -0.25, 0.25)gen.add("allow_unsafe_settings",bool_t,   SensorLevels.RECONFIGURE_CLOSE,        "Turn this on if you wish to use the UTM-30LX with an unsafe angular range. Turning this option on may cause occasional crashes or bad data. This option is a tempory workaround that will hopefully be removed in an upcoming driver version.",         False)exit(gen.generate(PACKAGE, "dynamic_reconfigure_node", "MyStuff"))

这里尤其要注意最后一句的第三个参数，必须与config文件同名，我们的config文件名为MyStuff.cfg所以这里为Mytuff。而且第三个参数也决定着我们的config头文件的名称，后面埋个伏笔，头文件生成的名称为MyStuffConfig.h也即，第三个参数加上Config.h.

修改cfg文件的权限

chmod a+x MyStuff.cfg

2.修改依赖项

在manifest.xml文件中加入依赖项即：

<build_depend>dynamic_reconfigure</build_depend>
<build_depend>driver_base</build_depend>

<run_depend>dynamic_reconfigure</run_depend>
<run_depend>driver_base</run_depend>

3.创建server主函数

在src文件夹下建立一个名为dynamic_reconfigure_node.cpp的文件，代码如下，尤其注意这里的第二个头文件的包含，因为我发现编译的时候，生成的config的头文件编译时放在了cfg文件夹下的cpp文件夹中，这个是catkin_make（catkin_make __force-cmake）的时候创建的，但是按照官网的路径它查找不到，我们干脆拷贝到src文件夹下

#include <dynamic_reconfigure/server.h>#include "MyStuffConfig.h"#include <ros/ros.h>void callback(beginner_tutorials::MyStuffConfig &config, uint32_t level){  ROS_INFO("Reconfigure request : %f %f %i %i %i %s %i %s %f %i",           config.groups.angles.min_ang,           config.groups.angles.max_ang,           (int)config.intensity,           config.cluster,           config.skip,           config.port.c_str(),           (int)config.calibrate_time,           config.frame_id.c_str(),           config.time_offset,           (int)config.allow_unsafe_settings);  // do nothing for now}int main(int argc, char **argv){  ros::init(argc, argv, "dynamic_reconfigure_node");  dynamic_reconfigure::Server<beginner_tutorials::MyStuffConfig> srv;  dynamic_reconfigure::Server<beginner_tutorials::MyStuffConfig>::CallbackType f;  f = boost::bind(&callback, _1, _2);  srv.setCallback(f);  ROS_INFO("Starting to spin...");  ros::spin();  return 0;}

4.关于CMakeList.txt的修改

这个文件相信大家不陌生，但是也是最头疼的地方，编译的错误好多都是设置不当引起的。我直接贴上来

cmake_minimum_required(VERSION 2.8.3)project(beginner_tutorials)find_package(catkin REQUIRED COMPONENTS  roscpp  rospy  std_msgs  message_generation  dynamic_reconfigure)################################################## Declare ROS messages, services and actions #################################################### To declare and build messages, services or actions from within this## package, follow these steps:## * Let MSG_DEP_SET be the set of packages whose message types you use in##   your messages/services/actions (e.g. std_msgs, actionlib_msgs, ...).## * In the file package.xml:##   * add a build_depend and a run_depend tag for each package in MSG_DEP_SET##   * If MSG_DEP_SET isn't empty the following dependencies might have been##     pulled in transitively but can be declared for certainty nonetheless:##     * add a build_depend tag for "message_generation"##     * add a run_depend tag for "message_runtime"## * In this file (CMakeLists.txt):##   * add "message_generation" and every package in MSG_DEP_SET to##     find_package(catkin REQUIRED COMPONENTS ...)##   * add "message_runtime" and every package in MSG_DEP_SET to##     catkin_package(CATKIN_DEPENDS ...)##   * uncomment the add_*_files sections below as needed##     and list every .msg/.srv/.action file to be processed##   * uncomment the generate_messages entry below##   * add every package in MSG_DEP_SET to generate_messages(DEPENDENCIES ...)## Generate messages in the 'msg' folder add_message_files(  FILES  Num.msg )## Generate services in the 'srv' folder add_service_files(   FILES   AddTwoInts.srv    )## Generate actions in the 'action' folder# add_action_files(#   FILES#   Action1.action#   Action2.action# )## Generate added messages and services with any dependencies listed heregenerate_messages(  DEPENDENCIES  std_msgs )# for dynamic reconfiguregenerate_dynamic_reconfigure_options(  cfg/MyStuff.cfg  )##################################### catkin specific configuration ####################################### The catkin_package macro generates cmake config files for your package## Declare things to be passed to dependent projects## INCLUDE_DIRS: uncomment this if you package contains header files## LIBRARIES: libraries you create in this project that dependent projects also need## CATKIN_DEPENDS: catkin_packages dependent projects also need## DEPENDS: system dependencies of this project that dependent projects also needcatkin_package( CATKIN_DEPENDS message_runtime)############# Build ############### Specify additional locations of header files## Your package locations should be listed before other locationsinclude_directories(${dynamic_reconfigure_PACKAGE_PATH}/cmake/cfgbuild.cmake)include_directories(${catkin_INCLUDE_DIRS})## Declare a cpp library# add_library(beginner_tutorials#   src/${PROJECT_NAME}/beginner_tutorials.cpp# )## Declare a cpp executable# add_executable(beginner_tutorials_node src/beginner_tutorials_node.cpp)add_executable(talker src/talker.cpp)add_executable(listener src/listener.cpp)# for dynamic reconfigureadd_executable(dynamic_reconfigure_node src/dynamic_reconfigure_node.cpp)add_executable(add_two_ints_server src/add_two_ints_server.cpp)add_executable(add_two_ints_client src/add_two_ints_client.cpp)## Add cmake target dependencies of the executable/library## as an example, message headers may need to be generated before nodes# add_dependencies(beginner_tutorials_node beginner_tutorials_generate_messages_cpp)# for dynamic reconfigureadd_dependencies(dynamic_reconfigure_node beginner_tutorials_gencfg)# for python dynamic clientadd_dependencies(dynamic_reconfigure_node beginner_tutorials_generate_messages_cpp)add_dependencies(talker beginner_tutorials_generate_messages_cpp)add_dependencies(listener beginner_tutorials_generate_messages_cpp)add_dependencies(add_two_ints_server beginner_tutorials_gencpp)add_dependencies(add_two_ints_client beginner_tutorials_gencpp)## Specify libraries to link a library or executable target against# target_link_libraries(beginner_tutorials_node ${catkin_LIBRARIES} )# for dynamic reconfiguretarget_link_libraries(dynamic_reconfigure_node ${catkin_LIBRARIES})target_link_libraries(talker ${catkin_LIBRARIES})target_link_libraries(listener ${catkin_LIBRARIES})target_link_libraries(add_two_ints_server ${catkin_LIBRARIES})target_link_libraries(add_two_ints_client ${catkin_LIBRARIES})############### Install ################ all install targets should use catkin DESTINATION variables# See http://ros.org/doc/api/catkin/html/adv_user_guide/variables.html## Mark executable scripts (Python etc.) for installation## in contrast to setup.py, you can choose the destination# install(PROGRAMS#   scripts/my_python_script#   DESTINATION ${CATKIN_PACKAGE_BIN_DESTINATION}# )## Mark executables and/or libraries for installation# install(TARGETS beginner_tutorials beginner_tutorials_node#   ARCHIVE DESTINATION ${CATKIN_PACKAGE_LIB_DESTINATION}#   LIBRARY DESTINATION ${CATKIN_PACKAGE_LIB_DESTINATION}#   RUNTIME DESTINATION ${CATKIN_PACKAGE_BIN_DESTINATION}# )## Mark cpp header files for installation# install(DIRECTORY include/${PROJECT_NAME}/#   DESTINATION ${CATKIN_PACKAGE_INCLUDE_DESTINATION}#   FILES_MATCHING PATTERN "*.h"#   PATTERN ".svn" EXCLUDE# )## Mark other files for installation (e.g. launch and bag files, etc.)# install(FILES#   # myfile1#   # myfile2#   DESTINATION ${CATKIN_PACKAGE_SHARE_DESTINATION}# )############### Testing ################# Add gtest based cpp test target and link libraries# catkin_add_gtest(${PROJECT_NAME}-test test/test_beginner_tutorials.cpp)# if(TARGET ${PROJECT_NAME}-test)#   target_link_libraries(${PROJECT_NAME}-test ${PROJECT_NAME})# endif()## Add folders to be run by python nosetests# catkin_add_nosetests(test)

关于dynamic reconfig的主要几句是

find_package(catkin REQUIRED COMPONENTS
  roscpp
  rospy
  std_msgs
  message_generation
  dynamic_reconfigure
)

generate_dynamic_reconfigure_options(
  cfg/MyStuff.cfg
 
)

include_directories(${dynamic_reconfigure_PACKAGE_PATH}/cmake/cfgbuild.cmake)

add_executable(dynamic_reconfigure_node src/dynamic_reconfigure_node.cpp)这里生成可执行的node文件，node名字是dynamic_reconfigure_node

add_dependencies(dynamic_reconfigure_node beginner_tutorials_gencfg)也有写成${PROJECT_NAME}_gencfg的

target_link_libraries(dynamic_reconfigure_node ${catkin_LIBRARIES})生成可执行的node文件，node名字是dynamic_reconfigure_node

5.测试用的程序

测试用到的程序，其实我在这里仿照了http://wiki.ros.org/dynamic_reconfigure/Tutorials/中的client.py的写法，但是它的有个缺点，按照ros.rate(0.1)即0.1Hz也即10s一次，他会复位，就是你调整的参数10s后就由默认值替代了，我这里修改了一下，让他不会复位

在src中放入一个名为yakeclient.py的文件，这里就是客户端了

#!/usr/bin/env pythonPACKAGE = 'beginner_tutorials'import roslib;roslib.load_manifest(PACKAGE)import rospyimport dynamic_reconfigure.clientdef callback(config):    rospy.loginfo("Config set to {min_ang}, {max_ang}, {intensity}, {cluster}, {skip}, {port}, {calibrate_time}, {frame_id}, {time_offset},{allow_unsafe_settings}".format(**config))   if __name__ == "__main__":    rospy.init_node("yakeclient")# Client first argument is the node names    client = dynamic_reconfigure.client.Client("dynamic_reconfigure_node", timeout=30, config_callback=callback)    r = rospy.Rate(0.1)    #x = 0    #b = False     while not rospy.is_shutdown():        #x = x+1        #if x>10:        #    x=0        #b = not b       # client.update_configuration({"int_param":x, "double_param":(1/(x+1)), "str_param":str(rospy.get_rostime()), "bool_param":b, "size":1})    r.sleep()

6.编译并启动程序

7.对比官方教程

这里我们可以看到其实结构都是一样的，最主要的区别还是在于config文件的定义，而他是完全自由的，完全由设计者考虑，需要动态调整一些什么样子的参数。

从下面的这个详细的节点关系图，我们可以看出，其实rqt_reconfig也即图中的rqt_gui_py_node_9301，就是一个client。那个9507是rqt_graph

关掉我们自己的yakeclient如图所示。因此自己的那个client目前只有显示的作用，（即只能看到设定的值）。而rqt_reconfig则包含了设置与显示。所以一般情况下，我们所要做的就是写dynamic server，利用rqt_reconfig作为client来设定目标值。

8.总结

这些内容写起来容易，但是自己花了差不多两天才解决掉，其中主要卡在了cfg.h上，因为系统编译老是提示找不到它，如果你也有这样的问题，首先看看CMakeList.txt内容是否正确，二，就像我之前那样，生成的头文件居然放在cfg文件夹里了。还有就是Client.py文件的写法。我当时起得名字叫yakeclient.py，观察rqt_graph时的节点信息老是订阅不了topic

像上图中的一样，然后仔细查看才发现python中的文件第17行

这里我想当然理解为了package name其实它应该是publisher 的名称，也就是server的名称，这里我们的server节点是dynamic_reconfigure_node所以改完以后就Ok了。引以为戒。