参考:《ROS机器人开发实践》
注:在 catkin_ws 工作空间下的功能包 learning_communication 下继续实现通信编程
一、动作通讯模型
二、动作编程实现
1、服务编程流程:
1、创建服务器;
2、创建客户端;
3、添加编译选项;
4、运行可执行文件;
2、自定义动作文件action
a、在learning_communication下创建action目录,在action目录下创建DoDishes.action文件
#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
b、在package.xml中添加功能包依赖
<build_depend>actionlib</build_depend>
<build_depend>actionlib_msgs</build_depend>
<exec_depend>actionlib</exec_depend>
<exec_depend>actionlib_msgs</exec_depend>
c、在CMakeLists.txt中添加编译选项
find_package(catkin REQUIRED COMPONENTS
...
actionlib_msgs
actionlib
)
add_action_files(DIRECTORY action FILES DoDishes.action)
generate_messages(DEPENDENCIES std_msgs actionlib_msgs)
d、编译
在 catkin_ws 工作空间下生成可执行文件:
catkin_make
3、创建动作服务器
a、在如下目录下创建DoDishes_server.cpp文件:
b、DoDishes_server.cpp文件代码如下:
#include <ros/ros.h>
#include <actionlib/server/simple_action_server.h>
#include "learning_communication/DoDishesAction.h"
typedef actionlib::SimpleActionServer<learning_communication::DoDishesAction> Server;
// 收到action的goal后调用该回调函数
void execute(const learning_communication::DoDishesGoalConstPtr& goal, Server* as)
{
ros::Rate r(1);
learning_communication::DoDishesFeedback feedback;
ROS_INFO("Dishwasher %d is working.", goal->dishwasher_id);
// 假设洗盘子的进度,并且按照1hz的频率发布进度feedback
for(int i=1; i<=10; i++)
{
feedback.percent_complete = i * 10;
as->publishFeedback(feedback);
r.sleep();
}
// 当action完成后,向客户端返回结果
ROS_INFO("Dishwasher %d finish working.", goal->dishwasher_id);
as->setSucceeded();
}
int main(int argc, char** argv)
{
ros::init(argc, argv, "do_dishes_server");
ros::NodeHandle n;
// 定义一个服务器
Server server(n, "do_dishes", boost::bind(&execute, _1, &server), false);
// 服务器开始运行
server.start();
ros::spin();
return 0;
}
c、实现逻辑
(1)初始化ROS节点;
(2)创建动作服务器实例;
(3)启动服务器,等待动作请求;
(4)在回调函数中完成动作服务功能的处理,并反馈进度信息;
(5)动作完成,发送结束信息;
4、创建动作客户端
a、在如下目录下创建DoDishes_client.cpp文件:
b、DoDishes_client.cpp文件代码如下:
#include <actionlib/client/simple_action_client.h>
#include "learning_communication/DoDishesAction.h"
typedef actionlib::SimpleActionClient<learning_communication::DoDishesAction> Client;
// 当action完成后会调用该回调函数一次
void doneCb(const actionlib::SimpleClientGoalState& state,
const learning_communication::DoDishesResultConstPtr& result)
{
ROS_INFO("Yay! The dishes are now clean");
ros::shutdown();
}
// 当action激活后会调用该回调函数一次
void activeCb()
{
ROS_INFO("Goal just went active");
}
// 收到feedback后调用该回调函数
void feedbackCb(const learning_communication::DoDishesFeedbackConstPtr& feedback)
{
ROS_INFO(" percent_complete : %f ", feedback->percent_complete);
}
int main(int argc, char** argv)
{
ros::init(argc, argv, "do_dishes_client");
// 定义一个客户端
Client client("do_dishes", true);
// 等待服务器端
ROS_INFO("Waiting for action server to start.");
client.waitForServer();
ROS_INFO("Action server started, sending goal.");
// 创建一个action的goal
learning_communication::DoDishesGoal goal;
goal.dishwasher_id = 1;
// 发送action的goal给服务器端,并且设置回调函数
client.sendGoal(goal, &doneCb, &activeCb, &feedbackCb);
ros::spin();
return 0;
}
c、实现逻辑
(1)初始化ROS节点;
(2)创建动作客户端实例;
(3)连接动作服务器;
(4)发送动作目标;
(5)根据不同类型的服务端反馈处理回调函数
5、添加编译选项
编译方法
在 CMakeLists.txt 文件中进行编译代码:
(1)设置需要编译的代码和生成的可执行文件;
(2)设置链接库;
(3)设置依赖;
具体操作
打开learning_communication功能包中的 CMakeLists.txt 文件,添加如下代码:
add_executable(DoDishes_client src/DoDishes_client.cpp)
target_link_libraries(DoDishes_client ${catkin_LIBRARIES})
add_dependencies(DoDishes_client ${${PROJECT_NAME}_EXPORTED_TARGETS})
add_executable(DoDishes_server src/DoDishes_server.cpp)
target_link_libraries(DoDishes_server ${catkin_LIBRARIES})
add_dependencies(DoDishes_server ${${PROJECT_NAME}_EXPORTED_TARGETS})
生成
在 catkin_ws 工作空间下生成可执行文件:
catkin_make
6、运行可执行文件
注意每次打开新终端添加环境变量:(需要手动添加的话)
source ~/test/catkin_ws/devel/setup.bash
a、请ROS Master
新打开终端:
roscore
b、启动client
新打开终端:
rosrun learning_communication DoDishes_client
c、启动server
新打开终端:
rosrun learning_communication DoDishes_server