turtle_tf_listener.py
Go to the documentation of this file.00001 #!/usr/bin/env python 00002 # Software License Agreement (BSD License) 00003 # 00004 # Copyright (c) 2008, Willow Garage, Inc. 00005 # All rights reserved. 00006 # 00007 # Redistribution and use in source and binary forms, with or without 00008 # modification, are permitted provided that the following conditions 00009 # are met: 00010 # 00011 # * Redistributions of source code must retain the above copyright 00012 # notice, this list of conditions and the following disclaimer. 00013 # * Redistributions in binary form must reproduce the above 00014 # copyright notice, this list of conditions and the following 00015 # disclaimer in the documentation and/or other materials provided 00016 # with the distribution. 00017 # * Neither the name of the Willow Garage nor the names of its 00018 # contributors may be used to endorse or promote products derived 00019 # from this software without specific prior written permission. 00020 # 00021 # THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 00022 # "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 00023 # LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS 00024 # FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE 00025 # COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, 00026 # INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, 00027 # BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; 00028 # LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER 00029 # CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 00030 # LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN 00031 # ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 00032 # POSSIBILITY OF SUCH DAMAGE. 00033 00034 import roslib 00035 roslib.load_manifest('turtle_tf') 00036 import rospy 00037 00038 import math 00039 import tf 00040 import turtlesim.msg 00041 import turtlesim.srv 00042 00043 if __name__ == '__main__': 00044 rospy.init_node('tf_turtle') 00045 00046 listener = tf.TransformListener() 00047 00048 rospy.wait_for_service('spawn') 00049 spawner = rospy.ServiceProxy('spawn', turtlesim.srv.Spawn) 00050 spawner(4, 2, 0, 'turtle2') 00051 00052 turtle_vel = rospy.Publisher('turtle2/command_velocity', turtlesim.msg.Velocity) 00053 00054 rate = rospy.Rate(10.0) 00055 while not rospy.is_shutdown(): 00056 try: 00057 (trans,rot) = listener.lookupTransform('/turtle2', '/turtle1', rospy.Time()) 00058 except (tf.LookupException, tf.ConnectivityException): 00059 continue 00060 00061 angular = 4 * math.atan2(trans[1], trans[0]) 00062 linear = 0.5 * math.sqrt(trans[0] ** 2 + trans[1] ** 2) 00063 turtle_vel.publish(turtlesim.msg.Velocity(linear, angular)) 00064 00065 rate.sleep()