ROS action使用范例 roscpp 版本

action的基本用法，包括客户端与服务端的执行和反馈等。

首先保证ROS已经安装。

1. 创建 catkin 空间

mkdir -p catkin_ws/src
cd catkin_ws
catkin_make

此时如果出错，说明ROS没有正确安装。

2. 创建 package ： action_demo

取包名为action_demo，并且创建必要的文件夹。

cd src
catkin_create_pkg action_demo roscpp rospy std_msgs

cd action_demo
mkdir src
mkdir action

3. 编辑 action_demo 内容 使用roscpp

3.1 新建 DoDishes.action

创建 action_demo/action/DoDishes.action

# Define the goal
uint32 dishwasher_id  # Specify which dishwasher we want to use
---
# Define the result
uint32 total_dishes_cleaned
---
# Define a feedback message
float32 percent_complete

3.2 修改 CMakeLists.txt

以下是修改部分，可通过取消注释然后修改的方式来做

find_package(catkin REQUIRED COMPONENTS
  roscpp
  rospy
  std_msgs
  genmsg actionlib_msgs actionlib   #add
)


add_action_files(
    DIRECTORY action 
    FILES DoDishes.action
)

generate_messages(
  DEPENDENCIES
  std_msgs
  actionlib_msgs    # add
)

3.3 修改 package.xml

增加如下内容

<build_depend>actionlib</build_depend>
<build_depend>actionlib_msgs</build_depend>
<exec_depend>actionlib</exec_depend>
<exec_depend>actionlib_msgs</exec_depend>

上面是format2的，也可以写成下面的format1的，两种格式都可以

<build_depend>actionlib</build_depend>
<build_depend>actionlib_msgs</build_depend>
<run_depend>actionlib</run_depend> 
<run_depend>actionlib_msgs</run_depend>

3.4 返回 catkin_ws 编译

返回工作空间catkin_ws

然后 catkin_make ，看是否能够编译成功，如果报错，先解决错误，再往下走

3.5 新建 dishes_server.cpp

创建 action_demo/src/dishes_server.cpp

#include <ros/ros.h>
#include <actionlib/server/simple_action_server.h>
#include "action_demo/DoDishesAction.h"

typedef actionlib::SimpleActionServer<action_demo::DoDishesAction> Server;

// execute when receive a goal from client
void execute(const action_demo::DoDishesGoalConstPtr& goal, Server* as)
{
    ros::Rate rate(1);
    action_demo::DoDishesFeedback feedback;

    ROS_INFO("Dishwasher %d is working.", goal->dishwasher_id);

    // publish feedback
    for(int i=1; i<=10; i++) {
        feedback.percent_complete = i * 10;
        as->publishFeedback(feedback);
        rate.sleep();
    }

    // done. return result
    ROS_INFO("Dishwasher %d finish working.", goal->dishwasher_id);
    action_demo::DoDishesResult result;
    result.total_dishes_cleaned = 10;
    as->setSucceeded(result);
}

int main(int argc, char** argv)
{
    ros::init(argc, argv, "do_dishes_server");
    ros::NodeHandle nh;

    // create a server
    Server server(nh, "do_dishes", boost::bind(&execute, _1, &server), false);

    // start the server
    server.start();

    ros::spin();

    return 0;
}

3.6 新建 dishes_client.cpp

创建 action_demo/src/dishes_client.cpp

#include <ros/ros.h>
#include <actionlib/client/simple_action_client.h>
#include "action_demo/DoDishesAction.h"

typedef actionlib::SimpleActionClient<action_demo::DoDishesAction> Client;

// execute when the goal is done
void doneCb(const actionlib::SimpleClientGoalState& state,
        const action_demo::DoDishesResultConstPtr& result)
{
    ROS_INFO("Yay! The dishes(%d) are now clean", result->total_dishes_cleaned);
}

// execute when the goal is active
void activeCb()
{
    ROS_INFO("Goal just went active");
}

// execute when receiving the feedback from server
void feedbackCb(const action_demo::DoDishesFeedbackConstPtr& feedback)
{
    ROS_INFO(" percent_complete : %f ", feedback->percent_complete);
}

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

    // create a client
    Client client("do_dishes", true);

    // wait for server
    ROS_INFO("Waiting for action server to start.");
    client.waitForServer();
    ROS_INFO("Action server started, sending goal.");

    // create goal
    action_demo::DoDishesGoal goal;
    goal.dishwasher_id = 1;

    // send goal to server. set callback
    client.sendGoal(goal,  &doneCb, &activeCb, &feedbackCb);

    client.waitForResult();

    ros::Duration(1).sleep();

    return 0;
}

3.7 修改 CMakLists.txt

以下内容加载合适位置，注释标识的位置。如果没找到位置，就放到文件末尾。

add_executable(server src/dishes_server.cpp)    
add_dependencies(server ${${PROJECT_NAME}_EXPORTED_TARGETS} ${catkin_EXPORTED_TARGETS})
target_link_libraries(server ${catkin_LIBRARIES})

add_executable(client src/dishes_client.cpp)        
add_dependencies(client ${${PROJECT_NAME}_EXPORTED_TARGETS} ${catkin_EXPORTED_TARGETS})
target_link_libraries(client ${catkin_LIBRARIES})

3.8 编译运行

返回工作空间 catkin_ws

catkin_make
看是否编译成功，如果有错误，要逐个去解决

刷新环境
source ~/catkin_ws/devel/setup.bash
rospack profile

在一个终端开启roscore：
roscore

在一个终端开启server：
rosrun action_demo server

在一个终端开启client：
rosrun action_demo client

这样之后，就能看到信息输出

4. 参考

https://www.guyuehome.com/908
http://wiki.ros.org/actionlib