head_action_client.py

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#!/usr/bin/env python

# Copyright (c) 2013-2015, Rethink Robotics
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"""
Baxter RSDK Head Action Client Example
"""
import sys
import argparse

import rospy

import actionlib

from control_msgs.msg import (
    SingleJointPositionAction,
    SingleJointPositionGoal,
)

import baxter_interface

from baxter_interface import CHECK_VERSION

class HeadClient(object):
    def __init__(self):
        ns = 'robot/head/head_action'
        self._client = actionlib.SimpleActionClient(
            ns,
            SingleJointPositionAction
        )
        self._goal = SingleJointPositionGoal()

        # Wait 10 Seconds for the head action server to start or exit
        if not self._client.wait_for_server(rospy.Duration(10.0)):
            rospy.logerr("Exiting - Head Action Server Not Found")
            rospy.signal_shutdown("Action Server not found")
            sys.exit(1)
        self.clear()

    def command(self, position, velocity):
        self._goal.position = position
        self._goal.max_velocity = velocity
        self._client.send_goal(self._goal)

    def stop(self):
        self._client.cancel_goal()

    def wait(self, timeout=5.0):
        self._client.wait_for_result(timeout=rospy.Duration(timeout))
        return self._client.get_result()

    def clear(self):
        self._goal = SingleJointPositionGoal()

def main():
    """RSDK Head Example: Action Client

    Demonstrates creating a client of the Head Action Server,
    which enables sending commands of standard action type
    control_msgs/SingleJointPosition.

    The example will command the head to a position.
    Be sure to start Baxter's head_action_server before running this example.
    """
    arg_fmt = argparse.RawDescriptionHelpFormatter
    parser = argparse.ArgumentParser(formatter_class=arg_fmt,
                                     description=main.__doc__)
    parser.parse_args(rospy.myargv()[1:])

    print("Initializing node... ")
    rospy.init_node("rsdk_head_action_client")
    print("Getting robot state... ")
    rs = baxter_interface.RobotEnable(CHECK_VERSION)
    print("Enabling robot... ")
    rs.enable()
    print("Running. Ctrl-c to quit")

    hc = HeadClient()
    hc.command(position=0.0, velocity=1.0)
    hc.wait()
    hc.command(position=1.57, velocity=0.1)
    hc.wait()
    hc.command(position=0.0, velocity=0.8)
    hc.wait()
    hc.command(position=-1.0, velocity=0.4)
    hc.wait()
    hc.command(position=0.0, velocity=0.6)
    print hc.wait()
    print "Exiting - Head Action Test Example Complete"

if __name__ == "__main__":
    main()