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Writing the Action Client

Compiling opencupboard stack

If you have not downloaded the opencupboard stack, please do so by following:

svn co `roslocate svn opencupboard`

After you do that, make sure stack is compiled on your local machine by:

roscd opencupboard
rosmake

The opencupboard stack relies on implementation of pr_tabletop_manipulation, move_arm service, and ee_cart_imped force controller. For the specifics of these packages, please see tutorials for tabletop_manipulation, tutorials for move_arm, and tutorials for ee_cart_imped.

The Code

First, create a package for this tutorial. Open a new shell, navigate to a directory on your ROS_PACKAGE_PATH in which you wish to do the tutorial and type

roscreate-pkg opencupboard_tutorial opencupboard_action opencupboard_msgs opencupboard_launch actionlib

Within that package, create the scripts/action_client.py file and paste the following inside it:

   1 #!/usr/bin/env python
   2 import roslib; roslib.load_manifest('opencupboard_action')
   3 import rospy
   4 import actionlib
   5 import opencupboard_msgs.msg
   6 
   7 def main():
   8     '''
   9     Runs the openCupboard action. 
  10     '''
  11     open_cupboard_client = actionlib.SimpleActionClient( 'open_cupboard_action',opencupboard_msgs.msg.OpenCupboardAction)
  12     
  13     print "waiting for server"
  14     open_cupboard_client.wait_for_server()
  15 
  16     goal = opencupboard_msgs.msg.OpenCupboardGoal()
  17     goal.open_cupboard = True
  18     print "sending goal"
  19     open_cupboard_client.send_goal(goal)
  20 
  21     print "waiting for result"
  22     open_cupboard_client.wait_for_result()
  23 
  24     print "RESULT:",open_cupboard_client.get_result()
  25 
  26 if __name__ == '__main__':
  27     rospy.init_node('test_open_cupboard_action')
  28     main()

Examining the Code

   4 import actionlib
   5 import opencupboard_msgs.msg

These lines import the action library and the opencupboard_action's messages.

  11     open_cupboard_client = actionlib.SimpleActionClient( 'open_cupboard_action',opencupboard_msgs.msg.OpenCupboardAction)

This is the instantiation of the client. You must pass it the name of the action and the action messages.

  14     open_cupboard_client.wait_for_server()

Waits until the action server is running.

  16     goal = opencupboard_msgs.msg.OpenCupboardGoal()
  17     goal.open_cupboard = True

Creates a goal and sets open_cupboard to True. This just indicates that you want to execute the action.

  19     open_cupboard_client.send_goal(goal)
  20 
  21     print "waiting for result"
  22     open_cupboard_client.wait_for_result()

Sends the goal and waits for the result

Running the Code

Change your file to be executable:

roscd opencupboard_tutorial/scripts
chmod +x action_client.py

Now we are ready to run the code.