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_tf2') 00036 import rospy 00037 00038 import math 00039 import tf2_ros 00040 import geometry_msgs.msg 00041 import turtlesim.srv 00042 00043 if __name__ == '__main__': 00044 rospy.init_node('tf2_turtle') 00045 00046 tfBuffer = tf2_ros.Buffer() 00047 listener = tf2_ros.TransformListener(tfBuffer) 00048 00049 rospy.wait_for_service('spawn') 00050 spawner = rospy.ServiceProxy('spawn', turtlesim.srv.Spawn) 00051 spawner(4, 2, 0, 'turtle2') 00052 00053 turtle_vel = rospy.Publisher('turtle2/cmd_vel', geometry_msgs.msg.Twist, queue_size=1) 00054 00055 rate = rospy.Rate(10.0) 00056 while not rospy.is_shutdown(): 00057 try: 00058 trans = tfBuffer.lookup_transform('turtle2', 'turtle1', rospy.Time.now(), rospy.Duration(1.0)) 00059 except tf2_ros.Exception: 00060 continue 00061 00062 angular = 4 * math.atan2(trans.transform.translation.y, trans.transform.translation.x) 00063 linear = 0.5 * math.sqrt(trans.transform.translation.x ** 2 + trans.transform.translation.y ** 2) 00064 msg = geometry_msgs.msg.Twist() 00065 msg.linear.x = linear 00066 msg.angular.z = angular 00067 turtle_vel.publish(msg) 00068 00069 rate.sleep()