actionlib

使用actionlib的教程
http://wiki.ros.org/actionlib/Tutorials


==========================================================================

1 创建工程
cd ~/catkin_ws/src
catkin_create_pkg action std_msgs rospy
2 设计action定义文件，内容有goal feedback result
这个和service的srv文件很像，放置再工程目录的action目录下

duration time_to_wait   #goal，客户端发送的等待总时间
---
duration time_elapsed #result ,服务器端发送的等了多久，
uint32 updates_sent #更新多少次
---
duration time_elapsed # feedback，服务器端周期性的发送已等了多久
duration time_remaining #还剩多久

3 修改CMakeLists.txt文件，配置默认支持
3.1 增加模块actionlib_msgs
find_package(catkin REQUIRED COMPONENTS
.....    #其他已有模块
actionlib_msgs#增加
)
3.2 增加action服务定义文件
add_action_files(
 DIRECTORY action
 FILES Timer.action
)
3.3  action的msg
generate_messages(
DEPENDENCIES
actionlib_msgs
std_msgs
)
3.4 catkin的msg支持
catkin_package(
CATKIN_DEPENDS
actionlib_msgs
)

4 编译工程
cd ~/catkin_ws
catkin_make

5 编写action服务器端程序
#!/usr/bin/env python
import roslib; roslib.load_manifest('action')

import rospy
import time
import actionlib
from action.msg import TimerAction, TimerGoal, TimerResult
def do_timer(goal):
        start_time = time.time()
        time.sleep(goal.time_to_wait.to_sec())
        result = TimerResult()
        result.time_elapsed = rospy.Duration.from_sec(time.time() - start_time)
        result.updates_sent = 0
        server.set_succeeded(result)
rospy.init_node('timer_action_server')
server = actionlib.SimpleActionServer('timer', TimerAction, do_timer, False)
server.start()
rospy.spin()
6 编写ros的action客户端程序
#!/usr/bin/env python
import roslib; roslib.load_manifest('action')
import rospy
import actionlib
from action.msg import TimerAction, TimerGoal, TimerResult
rospy.init_node('timer_action_client')
client = actionlib.SimpleActionClient('timer', TimerAction)
client.wait_for_server()
goal = TimerGoal()
goal.time_to_wait = rospy.Duration.from_sec(5.0)
client.send_goal(goal)
client.wait_for_result()
print('Time elapsed: %f'%(client.get_result().time_elapsed.to_sec()))

7 测试运行（开四个终端）
roscore
rosrun action action_c.py
rosrun action action_s.py

8 查看信息
liao@liao-eagle:~/catkin_ws/src/action/src$ rostopic list
/rosout
/rosout_agg
/timer/cancel
/timer/feedback
/timer/goal
/timer/result
/timer/status

liao@liao-eagle:~/catkin_ws/src/action/src$ rostopic info /timer/goal
Type: action/TimerActionGoal

Publishers: None

Subscribers: 
 * /timer_action_server (http://liao-eagle:42857/)

liao@liao-eagle:~/catkin_ws/src/action/src$ rosmsg show TimerActionGoal
[action/TimerActionGoal]:
std_msgs/Header header
  uint32 seq
  time stamp
  string frame_id
actionlib_msgs/GoalID goal_id
  time stamp
  string id
action/TimerGoal goal
  duration time_to_wait

liao@liao-eagle:~/catkin_ws/src/action/src$ rosmsg show TimerGoal
[action/TimerGoal]:
duration time_to_wait

9 rqt_graph