joint_trajectory_client.py

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#!/usr/bin/env python

# Copyright (c) 2013-2014, Rethink Robotics
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"""
Baxter RSDK Joint Trajectory Action Client Example
"""
import argparse
import sys

from copy import copy

import rospy

import actionlib

from control_msgs.msg import (
    FollowJointTrajectoryAction,
    FollowJointTrajectoryGoal,
)
from trajectory_msgs.msg import (
    JointTrajectoryPoint,
)

import baxter_interface

from baxter_interface import CHECK_VERSION


class Trajectory(object):
    def __init__(self, limb):
        ns = 'robot/limb/' + limb + '/'
        self._client = actionlib.SimpleActionClient(
            ns + "follow_joint_trajectory",
            FollowJointTrajectoryAction,
        )
        self._goal = FollowJointTrajectoryGoal()
        server_up = self._client.wait_for_server(timeout=rospy.Duration(10.0))
        if not server_up:
            rospy.logerr("Timed out waiting for Joint Trajectory"
                         " Action Server to connect. Start the action server"
                         " before running example.")
            rospy.signal_shutdown("Timed out waiting for Action Server")
            sys.exit(1)
        self.clear(limb)

    def add_point(self, positions, time):
        point = JointTrajectoryPoint()
        point.positions = copy(positions)
        point.time_from_start = rospy.Duration(time)
        self._goal.trajectory.points.append(point)

    def start(self):
        self._goal.trajectory.header.stamp = rospy.Time.now()
        self._client.send_goal(self._goal)

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

    def wait(self, timeout=15.0):
        self._client.wait_for_result(timeout=rospy.Duration(timeout))

    def result(self):
        return self._client.get_result()

    def clear(self, limb):
        self._goal = FollowJointTrajectoryGoal()
        self._goal.trajectory.joint_names = [limb + '_' + joint for joint in \
            ['s0', 's1', 'e0', 'e1', 'w0', 'w1', 'w2']]


def main():
    """RSDK Joint Trajectory Example: Simple Action Client

    Creates a client of the Joint Trajectory Action Server
    to send commands of standard action type,
    control_msgs/FollowJointTrajectoryAction.

    Make sure to start the joint_trajectory_action_server.py
    first. Then run this example on a specified limb to
    command a short series of trajectory points for the arm
    to follow.
    """
    arg_fmt = argparse.RawDescriptionHelpFormatter
    parser = argparse.ArgumentParser(formatter_class=arg_fmt,
                                     description=main.__doc__)
    required = parser.add_argument_group('required arguments')
    required.add_argument(
        '-l', '--limb', required=True, choices=['left', 'right'],
        help='send joint trajectory to which limb'
    )
    args = parser.parse_args(rospy.myargv()[1:])
    limb = args.limb

    print("Initializing node... ")
    rospy.init_node("rsdk_joint_trajectory_client_%s" % (limb,))
    print("Getting robot state... ")
    rs = baxter_interface.RobotEnable(CHECK_VERSION)
    print("Enabling robot... ")
    rs.enable()
    print("Running. Ctrl-c to quit")
    positions = {
        'left':  [-0.11, -0.62, -1.15, 1.32,  0.80, 1.27,  2.39],
        'right':  [0.11, -0.62,  1.15, 1.32, -0.80, 1.27, -2.39],
    }

    traj = Trajectory(limb)
    rospy.on_shutdown(traj.stop)

    p1 = positions[limb]
    traj.add_point(p1, 7.0)
    traj.add_point([x * 0.75 for x in p1], 9.0)
    traj.add_point([x * 1.25 for x in p1], 12.0)
    traj.start()
    traj.wait(15.0)
    print("Exiting - Joint Trajectory Action Test Complete")

if __name__ == "__main__":
    main()