tf 监听自己的坐标按官方例子一直不行不问题

问题：

tf 监听自己的坐标按官方例子一直不行不问题

解决方法 ： 

示例：

#!/usr/bin/env python
# Software License Agreement (BSD License)
#
# Copyright (c) 2008, Willow Garage, Inc.
# All rights reserved.
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions
# are met:
#
#  * Redistributions of source code must retain the above copyright
#    notice, this list of conditions and the following disclaimer.
#  * Redistributions in binary form must reproduce the above
#    copyright notice, this list of conditions and the following
#    disclaimer in the documentation and/or other materials provided
#    with the distribution.
#  * Neither the name of the Willow Garage nor the names of its
#    contributors may be used to endorse or promote products derived
#    from this software without specific prior written permission.
#
# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
# FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
# COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
# INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
# BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
# LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
# CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
# LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
# ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
# POSSIBILITY OF SUCH DAMAGE.

import rospy

import math
import tf
import geometry_msgs.msg
import turtlesim.srv

if __name__ == '__main__':
    rospy.init_node('turtle_tf_listener')

    listener = tf.TransformListener()

    rospy.wait_for_service('spawn')
    spawner = rospy.ServiceProxy('spawn', turtlesim.srv.Spawn)
    spawner(4, 2, 0, 'robot0')

    turtle_vel = rospy.Publisher(
        'robot1/cmd_vel', geometry_msgs.msg.Twist, queue_size=1)

    rate = rospy.Rate(10.0)

    listener.waitForTransform("/robot1", "/robot0",
                              rospy.Time(), rospy.Duration(4.0))
    while not rospy.is_shutdown():
        try:
            # (trans, rot) = listener.lookupTransform(
              #  '/turtle2', '/carrot1', rospy.Time())

            now = rospy.Time.now()
            listener.waitForTransform(
                "/robot1", "/robot0", now, rospy.Duration(4.0))
            (trans, rot) = listener.lookupTransform("/robot1", "/robot0", now)
        except (tf.LookupException, tf.ConnectivityException, tf.ExtrapolationException):
            continue

        angular = 4 * math.atan2(trans[1], trans[0])
        linear = 0.5 * math.sqrt(trans[0] ** 2 + trans[1] ** 2)
        msg = geometry_msgs.msg.Twist()
        msg.linear.x = linear
        msg.angular.z = angular
        turtle_vel.publish(msg)

        rate.sleep()

　　问题原因：

自己的示例没有以下的service  

 rospy.wait_for_service('spawn')
 spawner = rospy.ServiceProxy('spawn', turtlesim.srv.Spawn)

更改为成以下代码问题解决

#!/usr/bin/env python
# Software License Agreement (BSD License)
#
# Copyright (c) 2008, Willow Garage, Inc.
# All rights reserved.
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions
# are met:
#
#  * Redistributions of source code must retain the above copyright
#    notice, this list of conditions and the following disclaimer.
#  * Redistributions in binary form must reproduce the above
#    copyright notice, this list of conditions and the following
#    disclaimer in the documentation and/or other materials provided
#    with the distribution.
#  * Neither the name of the Willow Garage nor the names of its
#    contributors may be used to endorse or promote products derived
#    from this software without specific prior written permission.
#
# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
# FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
# COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
# INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
# BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
# LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
# CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
# LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
# ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
# POSSIBILITY OF SUCH DAMAGE.

import rospy

import math
import tf
import geometry_msgs.msg
import turtlesim.srv

if __name__ == '__main__':
    print ("startddd")
    rospy.init_node('turtle_tf_listener')

    listener = tf.TransformListener()

    #rospy.wait_for_service('spawn')
    listener.waitForTransform('/robot1', '/robot0', rospy.Time(), rospy.Duration(1.0))

    #spawner = rospy.ServiceProxy('spawn', turtlesim.srv.Spawn)
    #spawner(4, 2, 0, 'robot0_laser_0')

    turtle_vel = rospy.Publisher(
        'robot1/cmd_vel', geometry_msgs.msg.Twist, queue_size=1)

    rate = rospy.Rate(10.0)

    listener.waitForTransform("/robot1", "/robot0",
                              rospy.Time(), rospy.Duration(4.0))
    while not rospy.is_shutdown():
        try:
            # (trans, rot) = listener.lookupTransform(
              #  '/turtle2', '/carrot1', rospy.Time())
            print('lakjdfl;kajdlfkajd;lk')
            now = rospy.Time.now()
            listener.waitForTransform("/robot1", "/robot0", now, rospy.Duration(4.0))
            (trans, rot) = listener.lookupTransform("/robot1", "/robot0", now)
           
        except (tf.LookupException, tf.ConnectivityException, tf.ExtrapolationException):
            continue

        angular = 4 * math.atan2(trans[1], trans[0])
        linear = 0.5 * math.sqrt(trans[0] ** 2 + trans[1] ** 2)
        msg = geometry_msgs.msg.Twist()
        msg.linear.x = linear
        msg.angular.z = angular
        turtle_vel.publish(msg)
        print(msg.linear.x+msg.linear.z)
        rate.sleep()