• ROS 消息订阅 状态同步 action 行为通讯方式

    理解行为:

    在执行一些耗时短的任务时没有问题，

    在执行一些耗时长的任务如让机器人从大厅的A点移动至B点时，服务会造成线程的阻塞，

    为了解决这一问题，ROS提供了行为执行耗时长的异步行为。

    行为的组织:

    ROS的行为由后缀为action的资源文件定义，放置在action目录下

    行为文件包含: 

    goal、result、feedback三部分的内容。三者之间通过“---”隔开。一个action文件的示例如下：

    1. #goal
    2. int32 total
    3.  
    4.  --- 
    5.  
    6. #result
    7. int32 sum
    8.  
    9. --- 
    10.  
    11. #feedback

    goal：任务目标

    cancel：请求取消任务

    status：通知client当前的状态

    feedback：周期反馈任务运行的监控数据

    result：向client发送任务的执行结果，这个只会发布一次

    Action行为的实现:

    当执行行为时，首先ActionClient发送“goal”请求给ActionServer，

    一旦ActionServer收到“goal”请求，

    ActionServer就为该“goal”请求创建一个状态机来跟踪其状态转换。

    然后ActionServer发送“feedback”消息给ActionClient反馈行为进度，

    当任务完成或ActionClient发送取消请求后，

    ActionServer发送“result”消息给ActionClient，

    需注意的是，“result”消息只能发送一次。

    Action行为的实现:

    在实现行为时，要考虑连接的时延和状态的可用性。

    客户端方法：

    1. void sendGoal(const Goal & goal,
    2.  SimpleDoneCallback done_cb = SimpleDoneCallback(),
    3.  SimpleActiveCallback active_cb = SimpleActiveCallback(), 
    4. SimpleFeedbackCallback feedback_cb = SimpleFeedbackCallback());
    5. bool waitForServer(const ros::Duration & timeout = ros::Duration(0, 0) )
    9. #  发送目标
    10. #  等待反馈
    11. #  等待激活
    12. #  结果发送给客户端

    服务端方法：

    1. void publishFeedback(const Feedback & feedback)
    2. bool isPreemptRequested();
    3. void setSucceeded(const Result & result = Result(), const std::string & text std::string(""));

    行为的实现：

    Action行为本质上是基于消息的发布/订阅实现的一种通信机制

    //ActionServer的实现

    1. class ActionServer : public ActionServerBase
    2.  
    3. { ......
    4. ros::NodeHandle node_;
    5. ros::Subscriber goal_sub_, cancel_sub_;
    6. ros::Publisher status_pub_, result_pub_, feedback_pub_;
    7. ros::Timer status_timer_;
    8. }

    //结果和反馈的发布

    1. result_pub_ = node_.advertise("result", static_cast(pub_queue_size)); 
    2. feedback_pub_ =node_.advertise("feedback", static_cast(pub_queue_size));
    3.  
    4.  
    5. # 形成队列

    自定义行为步骤：    

    编译执行 action依赖于actionlib、actionlib_msgs程序包。

    跑步例子实例：

    步骤1 创建自定义行为.action

    1. #goal
    2. int32 total
    3. ---
    4. #result
    5. int32 sum
    6. ---
    7. #feedback
    8. int32 number
    9.  
    10.  
    11.  
    12. # 总目标
    13. # 最终跑了多少
    14. # 正在跑多少

    步骤2 编写客户端文件 .client

    1. #include 
    2. #include 
    3. #include 
    4.  
    5. #include "example_5/RunningAction.h"
    6.  
    7. void doneCb(const actionlib::SimpleClientGoalState& state,
    8.             const example_5::RunningResultConstPtr& result){
    9.    ROS_INFO("the runing are now finished! the sum is %d",result->sum);
    10. }
    11.  
    12. void activeCb()
    13. {
    14.   ROS_INFO("Goal just went active");
    15. }
    16.  
    17. void feedbackCb(const example_5::RunningFeedbackConstPtr& feedback){
    18.     ROS_INFO("running number is :%d",feedback->number);               
    19. }
    20.  
    21.  
    22.  
    23. int main (int argc, char **argv)
    24. {
    25.   ros::init(argc, argv, "running_client");
    26.  
    27.   actionlib::SimpleActionClient actionClient("running", true);
    28.   //SimpleActionClient 实例子选择
    29.  
    30.  
    31.   ROS_INFO("Waiting for action server to start.");
    32.   actionClient.waitForServer(); //will wait for infinite time等待响应
    33.  
    34.   ROS_INFO("Action server started, sending goal.");
    35.   example_5::RunningGoal goal;
    36.   goal.total = 20;             //跑了20步
    37.   actionClient.sendGoal(goal,&doneCb,&activeCb,&feedbackCb);
    38.   //wait 50s
    39.   bool finished_before_timeout = actionClient.waitForResult(ros::Duration(50.0));
    40.   if (finished_before_timeout)  //如果超时
    41.   {
    42.     actionlib::SimpleClientGoalState state = actionClient.getState();
    43.     ROS_INFO("Action finished: %s",state.toString().c_str());
    44.   }                              //如果没超时
    45.   else{
    46.     actionClient.cancelGoal();
    47.     ROS_INFO("Action did not finish before the time out.");
    48.   }
    49.  
    50.   return 0;
    51. }

    步骤3 编写服务文件  .service

    1. #include 
    2. #include 
    3. #include 
    4.  
    5. class RunningAction
    6. {
    7. protected:
    8.  
    9.   ros::NodeHandle nh_;
    10.   // NodeHandle instance must be created before this line. Otherwise strange error occurs.
    11.   actionlib::SimpleActionServer actionServer;
    12.   std::string action_name_;
    13.   // create messages that are used to published feedback/result
    14.   example_5::RunningFeedback actionFeedback;
    15.   example_5::RunningResult actionResult;
    16.  
    17. public:
    18.  
    19.   RunningAction(std::string name):                          // 绑定回调目标和循环
    20.     actionServer(nh_, name, boost::bind(&RunningAction::executeCB, this, _1), false), 
    21.     action_name_(name)
    22.   {
    23.     actionServer.start();
    24.   }
    25.  
    26.   ~RunningAction(void)
    27.   {
    28.   }
    29.  
    30.   void executeCB(const example_5::RunningGoalConstPtr &goal)
    31.   {
    32.     // helper variables
    33.     ros::Rate r(1);
    34.     bool success = true;
    35.     // start executing the action
    36.     for(int i=1; i<=goal->total; i++)            // 判断是否被抢占了
    37.     {
    38.       // check that preempt has not been requested by the client
    39.       if (actionServer.isPreemptRequested() || !ros::ok())
    40.       {
    41.         ROS_INFO("%s: Preempted", action_name_.c_str());
    42.         // set the action state to preempted
    43.         actionServer.setPreempted();
    44.         success = false;
    45.         break;
    46.       }
    47.       actionFeedback.number++;
    48.       // publish the feedback
    49.       actionServer.publishFeedback(actionFeedback);
    50.       ROS_INFO("Executing, creating %i of total %i",actionFeedback.number,goal->total);
    51.       r.sleep();
    52.     }
    53.  
    54.     if(success)
    55.     {
    56.       actionResult.sum = actionFeedback.number;
    57.       ROS_INFO("%s: Succeeded", action_name_.c_str());
    58.       // set the action state to succeeded
    59.       actionServer.setSucceeded(actionResult);
    60.     }
    61.   }
    62.  
    63. };
    64.  
    65.  
    66.  
    67.  
    68.  
    69. int main(int argc, char** argv)
    70. {
    71.   ros::init(argc, argv, "running_server");
    72.  
    73.   RunningAction running("running");
    74.   ros::spin();
    75.  
    76.   return 0;
    77. }

    步骤4 package.xml、CMakeLists.txt配置

    1. cmake_minimum_required(VERSION 3.0.2)
    2. project(example_5)
    3.  
    4. ## Compile as C++11, supported in ROS Kinetic and newer
    5. # add_compile_options(-std=c++11)
    6.  
    7. ## Find catkin macros and libraries
    8. ## if COMPONENTS list like find_package(catkin REQUIRED COMPONENTS xyz)
    9. ## is used, also find other catkin packages
    10. find_package(catkin REQUIRED COMPONENTS
    11.   roscpp
    12.   rospy
    13.   std_msgs
    14.   actionlib
    15.   actionlib_msgs
    16. )
    17.  
    18. ## System dependencies are found with CMake's conventions
    19. # find_package(Boost REQUIRED COMPONENTS system)
    20.  
    21.  
    22. ## Uncomment this if the package has a setup.py. This macro ensures
    23. ## modules and global scripts declared therein get installed
    24. ## See http://ros.org/doc/api/catkin/html/user_guide/setup_dot_py.html
    25. # catkin_python_setup()
    26.  
    27. ################################################
    28. ## Declare ROS messages, services and actions ##
    29. ################################################
    30.  
    31. ## To declare and build messages, services or actions from within this
    32. ## package, follow these steps:
    33. ## * Let MSG_DEP_SET be the set of packages whose message types you use in
    34. ##   your messages/services/actions (e.g. std_msgs, actionlib_msgs, ...).
    35. ## * In the file package.xml:
    36. ##   * add a build_depend tag for "message_generation"
    37. ##   * add a build_depend and a exec_depend tag for each package in MSG_DEP_SET
    38. ##   * If MSG_DEP_SET isn't empty the following dependency has been pulled in
    39. ##     but can be declared for certainty nonetheless:
    40. ##     * add a exec_depend tag for "message_runtime"
    41. ## * In this file (CMakeLists.txt):
    42. ##   * add "message_generation" and every package in MSG_DEP_SET to
    43. ##     find_package(catkin REQUIRED COMPONENTS ...)
    44. ##   * add "message_runtime" and every package in MSG_DEP_SET to
    45. ##     catkin_package(CATKIN_DEPENDS ...)
    46. ##   * uncomment the add_*_files sections below as needed
    47. ##     and list every .msg/.srv/.action file to be processed
    48. ##   * uncomment the generate_messages entry below
    49. ##   * add every package in MSG_DEP_SET to generate_messages(DEPENDENCIES ...)
    50.  
    51. ## Generate messages in the 'msg' folder
    52. # add_message_files(
    53. #   FILES
    54. #   Message1.msg
    55. #   Message2.msg
    56. # )
    57.  
    58. ## Generate services in the 'srv' folder
    59. # add_service_files(
    60. #   FILES
    61. #   Service1.srv
    62. #   Service2.srv
    63. # )
    64.  
    65. ## Generate actions in the 'action' folder
    66. add_action_files(
    67.    FILES
    68.    Running.action
    69. )
    70.  
    71. ## Generate added messages and services with any dependencies listed here
    72. generate_messages(
    73.    DEPENDENCIES
    74.    std_msgs
    75.    actionlib_msgs
    76. )
    77.  
    78. ################################################
    79. ## Declare ROS dynamic reconfigure parameters ##
    80. ################################################
    81.  
    82. ## To declare and build dynamic reconfigure parameters within this
    83. ## package, follow these steps:
    84. ## * In the file package.xml:
    85. ##   * add a build_depend and a exec_depend tag for "dynamic_reconfigure"
    86. ## * In this file (CMakeLists.txt):
    87. ##   * add "dynamic_reconfigure" to
    88. ##     find_package(catkin REQUIRED COMPONENTS ...)
    89. ##   * uncomment the "generate_dynamic_reconfigure_options" section below
    90. ##     and list every .cfg file to be processed
    91.  
    92. ## Generate dynamic reconfigure parameters in the 'cfg' folder
    93. # generate_dynamic_reconfigure_options(
    94. #   cfg/DynReconf1.cfg
    95. #   cfg/DynReconf2.cfg
    96. # )
    97.  
    98. ###################################
    99. ## catkin specific configuration ##
    100. ###################################
    101. ## The catkin_package macro generates cmake config files for your package
    102. ## Declare things to be passed to dependent projects
    103. ## INCLUDE_DIRS: uncomment this if your package contains header files
    104. ## LIBRARIES: libraries you create in this project that dependent projects also need
    105. ## CATKIN_DEPENDS: catkin_packages dependent projects also need
    106. ## DEPENDS: system dependencies of this project that dependent projects also need
    107. catkin_package(
    108. #  INCLUDE_DIRS include
    109. #  LIBRARIES example_5
    110.    CATKIN_DEPENDS roscpp rospy std_msgs actionlib_msgs
    111. #  DEPENDS system_lib
    112. )
    113.  
    114. ###########
    115. ## Build ##
    116. ###########
    117.  
    118. ## Specify additional locations of header files
    119. ## Your package locations should be listed before other locations
    120. include_directories(
    121. # include
    122.   ${catkin_INCLUDE_DIRS}
    123. )
    124.  
    125. ## Declare a C++ library
    126. # add_library(${PROJECT_NAME}
    127. #   src/${PROJECT_NAME}/example_5.cpp
    128. # )
    129.  
    130. ## Add cmake target dependencies of the library
    131. ## as an example, code may need to be generated before libraries
    132. ## either from message generation or dynamic reconfigure
    133. # add_dependencies(${PROJECT_NAME} ${${PROJECT_NAME}_EXPORTED_TARGETS} ${catkin_EXPORTED_TARGETS})
    134.  
    135. ## Declare a C++ executable
    136. ## With catkin_make all packages are built within a single CMake context
    137. ## The recommended prefix ensures that target names across packages don't collide
    138. # add_executable(${PROJECT_NAME}_node src/example_5_node.cpp)
    139.  
    140. ## Rename C++ executable without prefix
    141. ## The above recommended prefix causes long target names, the following renames the
    142. ## target back to the shorter version for ease of user use
    143. ## e.g. "rosrun someones_pkg node" instead of "rosrun someones_pkg someones_pkg_node"
    144. # set_target_properties(${PROJECT_NAME}_node PROPERTIES OUTPUT_NAME node PREFIX "")
    145.  
    146. ## Add cmake target dependencies of the executable
    147. ## same as for the library above
    148. # add_dependencies(${PROJECT_NAME}_node ${${PROJECT_NAME}_EXPORTED_TARGETS} ${catkin_EXPORTED_TARGETS})
    149.  
    150. ## Specify libraries to link a library or executable target against
    151. # target_link_libraries(${PROJECT_NAME}_node
    152. #   ${catkin_LIBRARIES}
    153. # )
    154. if(CMAKE_BUILD_TYPE STREQUAL DEBUG)
    155. add_executable(action_service src/service.cpp)
    156. add_executable(action_client src/client.cpp)
    157. target_link_libraries(action_service
    158.    ${catkin_LIBRARIES}
    159. )
    160. target_link_libraries(action_client
    161.    ${catkin_LIBRARIES}
    162. )
    163. endif()
    164. #############
    165. ## Install ##
    166. #############
    167.  
    168. # all install targets should use catkin DESTINATION variables
    169. # See http://ros.org/doc/api/catkin/html/adv_user_guide/variables.html
    170.  
    171. ## Mark executable scripts (Python etc.) for installation
    172. ## in contrast to setup.py, you can choose the destination
    173. # catkin_install_python(PROGRAMS
    174. #   scripts/my_python_script
    175. #   DESTINATION ${CATKIN_PACKAGE_BIN_DESTINATION}
    176. # )
    177.  
    178. ## Mark executables for installation
    179. ## See http://docs.ros.org/melodic/api/catkin/html/howto/format1/building_executables.html
    180. # install(TARGETS ${PROJECT_NAME}_node
    181. #   RUNTIME DESTINATION ${CATKIN_PACKAGE_BIN_DESTINATION}
    182. # )
    183.  
    184. ## Mark libraries for installation
    185. ## See http://docs.ros.org/melodic/api/catkin/html/howto/format1/building_libraries.html
    186. # install(TARGETS ${PROJECT_NAME}
    187. #   ARCHIVE DESTINATION ${CATKIN_PACKAGE_LIB_DESTINATION}
    188. #   LIBRARY DESTINATION ${CATKIN_PACKAGE_LIB_DESTINATION}
    189. #   RUNTIME DESTINATION ${CATKIN_GLOBAL_BIN_DESTINATION}
    190. # )
    191.  
    192. ## Mark cpp header files for installation
    193. # install(DIRECTORY include/${PROJECT_NAME}/
    194. #   DESTINATION ${CATKIN_PACKAGE_INCLUDE_DESTINATION}
    195. #   FILES_MATCHING PATTERN "*.h"
    196. #   PATTERN ".svn" EXCLUDE
    197. # )
    198.  
    199. ## Mark other files for installation (e.g. launch and bag files, etc.)
    200. # install(FILES
    201. #   # myfile1
    202. #   # myfile2
    203. #   DESTINATION ${CATKIN_PACKAGE_SHARE_DESTINATION}
    204. # )
    205.  
    206. #############
    207. ## Testing ##
    208. #############
    209.  
    210. ## Add gtest based cpp test target and link libraries
    211. # catkin_add_gtest(${PROJECT_NAME}-test test/test_example_5.cpp)
    212. # if(TARGET ${PROJECT_NAME}-test)
    213. #   target_link_libraries(${PROJECT_NAME}-test ${PROJECT_NAME})
    214. # endif()
    215.  
    216. ## Add folders to be run by python nosetests
    217. # catkin_add_nosetests(test)

    PS：需要注意的亮点

     

    package.xml

    1. "1.0"?>
    2. "2">
    3.   example_5
    4.   0.0.0
    5.   The example_5 package
    6.  
    7.   
    8.   
    9.   
    10.   "miaozl@todo.todo">miaozl
    11.  
    12.  
    13.   
    14.   
    15.   
    16.   D
    17.   O
    18.   O
    19.   T
    20.  
    21.  
    22.   
    23.   
    24.   
    25.   
    26.  
    27.  
    28.   
    29.   
    30.   
    31.   
    32.  
    33.  
    34.   
    35.   
    36.   
    37.   
    38.   
    39.   
    40.   
    41.   
    42.   
    43.   
    44.   
    45.   
    46.   
    47.   
    48.   
    49.   
    50.   
    51.   
    52.   
    53.   
    54.   catkin
    55.   roscpp
    56.   rospy
    57.   std_msgs
    58.   actionlib_msgs
    59.   roscpp
    60.   rospy
    61.   std_msgs
    62.   actionlib_msgs
    63.   roscpp
    64.   rospy
    65.   std_msgs
    66.   message_generation
    67.  
    68.   
    69.   
    70.     
    71.  
    72.

    步骤5 生成行为头文件，编译

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  • 原文地址：https://blog.csdn.net/weixin_44025389/article/details/126470251