motion_square.py
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00001 #!/usr/bin/env python
00002 #       
00003 # License: BSD
00004 #   https://raw.github.com/yujinrobot/kobuki/master/kobuki_testsuite/LICENSE 
00005 #
00006 ##############################################################################
00007 # Imports
00008 ##############################################################################
00009 
00010 import rospy
00011 import copy
00012 import math
00013 import PyKDL
00014 from nav_msgs.msg import Odometry
00015 from geometry_msgs.msg import Twist
00016 from std_msgs.msg import String
00017 from sensor_msgs.msg import Imu
00018 
00019 ##############################################################################
00020 # Classes
00021 ##############################################################################
00022 
00023 class Pose2D(object):
00024     def __init__(self):
00025         self.x = None
00026         self.y = None
00027         self.heading = None
00028         
00029     def configured(self):
00030         return self.x and self.y and self.heading
00031     
00032     def __str__(self):
00033         return ("[%s, %s, %s]"%(self.x, self.y, self.heading))
00034 
00035 '''
00036     Implement a square motion
00037 '''
00038 class Square(object):
00039     STATE_FORWARD = "forward"
00040     STATE_STOP_FORWARD = "stop_forward"
00041     STATE_TURN = "turn"
00042     STATE_STOP_TURN = "stop_turn"
00043     
00044     def __init__(self,cmd_vel_topic, odom_topic, gyro_topic):
00045         self._rate = rospy.Rate(20)
00046         self._speed = 0.4
00047         self._side_distance = 1.0
00048         
00049         self._stop = False
00050         self._running = False
00051         self._turn_count = 0
00052 
00053         self._current_pose = Pose2D()
00054         self._starting_pose = None
00055         self._state = Square.STATE_FORWARD
00056         self.last_state = Square.STATE_FORWARD
00057 
00058         self.odom_subscriber = rospy.Subscriber(odom_topic, Odometry, self.odometry_callback)
00059         self.cmd_vel_publisher = rospy.Publisher(cmd_vel_topic,Twist)
00060         self.gyro_subscriber  = rospy.Subscriber(gyro_topic, Imu, self.heading_callback)
00061 
00062     def init(self, speed, side_distance):
00063         # check for suitable values here
00064         self._speed = speed
00065         self._side_distance = side_distance
00066 
00067     def shutdown(self):
00068         self.stop()
00069         while self._running:
00070             rospy.sleep(0.5)
00071         self.cmd_vel_publisher.unregister()
00072         self.cmd_vel_publisher = None
00073         self.odom_subscriber.unregister()
00074         self.odom_subscriber = None
00075         self.gyro_subscriber.unregister()
00076         self.gyro_subscriber = None
00077         
00078     def stop(self):
00079         self._stop = True
00080 
00081     def execute(self):
00082         '''
00083           Drop this into threading.Thread or QThread for execution
00084         '''
00085         if self._running:
00086             rospy.logerr("Kobuki TestSuite: already executing a motion, ignoring the request")
00087             return
00088         timeout = rospy.Time.now() + rospy.Duration(5.0)
00089         while not self._current_pose.configured():
00090             if rospy.Time.now() > timeout:
00091                 rospy.logerr("Kobuki TestSuite: no odometry data, aborting")
00092                 return
00093             rospy.sleep(1.0)
00094             rospy.logwarn("Kobuki TestSuite: haven't received any odometry data yet")
00095         
00096         self._stop = False
00097         self._running = True
00098         start = rospy.get_rostime()
00099         rospy.sleep(0.5)
00100 
00101         #turning_arc_radius = side_distance/4.0
00102         rospy.loginfo("Kobuki Testsuite: executing a square motion pattern [%s]"%self._side_distance)
00103         self._starting_pose = copy.deepcopy(self._current_pose)
00104         
00105         while not self._stop and not rospy.is_shutdown():
00106             if self._state == Square.STATE_FORWARD:
00107                 self._forward()
00108             elif self._state == Square.STATE_STOP_FORWARD:
00109                 self._stop_forward()
00110             elif self._state == Square.STATE_TURN:
00111                 self._turn()
00112             elif self._state == Square.STATE_STOP_TURN:
00113                 self._stop_turn()
00114                 if self._turn_count == 4:
00115                     break
00116             self._rate.sleep()
00117         if not rospy.is_shutdown():
00118             self._command(0.0, 0.0)
00119         self._running = False
00120 
00121     ##########################################################################
00122     # Utilities
00123     ##########################################################################
00124     
00125     def _has_reached_forward_goal(self):
00126         dx = self._current_pose.x - self._starting_pose.x
00127         dy = self._current_pose.y - self._starting_pose.y
00128         travelled_sq = dx*dx + dy*dy
00129         if travelled_sq > self._side_distance*self._side_distance:
00130             return True
00131         else:
00132             return False
00133 
00134     def _has_reached_turning_goal(self):
00135         #rospy.loginfo("Poses [%s]-[%s]"%(self._current_pose.heading,self._starting_pose.heading))
00136         if math.fabs(self._current_pose.heading - self._starting_pose.heading) > math.pi/2.0:
00137             return True
00138         else:
00139             return False
00140     
00141     def _command(self, linear, angular):
00142         '''
00143           Publishes a cmd_vel message for the kobuki.
00144         '''
00145         cmd = Twist()
00146         cmd.linear.x = linear
00147         cmd.angular.z = angular
00148         self.cmd_vel_publisher.publish(cmd)
00149         
00150     def _forward(self):
00151         if self._has_reached_forward_goal():
00152             rospy.loginfo("Kobuki TestSuite: commencing turn")
00153             self._state = Square.STATE_STOP_FORWARD
00154             #self._command(0.0,0.0)
00155         else:
00156             self._command(self._speed, 0.0)
00157 
00158     def _stop_forward(self):
00159         self._starting_pose =  copy.deepcopy(self._current_pose)
00160         self._state = Square.STATE_TURN
00161         alpha = 0.5
00162         self._command(alpha*self._speed, -alpha*self._speed/(self._side_distance/4.0))
00163         
00164     def _turn(self):
00165         if self._has_reached_turning_goal():
00166             self._state = Square.STATE_STOP_TURN
00167             #self._command(0.0,0.0)
00168         else:
00169             # set up a turning arc, 1/4 the length of the side
00170             # actually, this almost always creates incredibly fast turns, so crank it down by alpha
00171             alpha = 0.5
00172             self._command(alpha*self._speed, -alpha*self._speed/(self._side_distance/4.0))
00173 
00174     def _stop_turn(self):
00175         self._turn_count = self._turn_count + 1
00176         rospy.loginfo("Kobuki TestSuite: finished turn %s"%self._turn_count)
00177         self._starting_pose =  copy.deepcopy(self._current_pose)
00178         self._state = Square.STATE_FORWARD
00179         if self._turn_count == 4:
00180             self._command(0.0, 0.0)
00181         else:
00182             self._command(self._speed, 0.0)
00183         
00184 
00185     ##########################################################################
00186     # Ros Callbacks
00187     ##########################################################################
00188 
00189     def odometry_callback(self, data):
00190         self._current_pose.x = data.pose.pose.position.x
00191         self._current_pose.y = data.pose.pose.position.y
00192         # if self._current_pose.configured():
00193         #     rospy.loginfo("TesSuite: %s"%self._current_pose)
00194 
00195     def heading_callback(self, data):
00196         quat = data.orientation
00197         rot = PyKDL.Rotation.Quaternion(quat.x, quat.y, quat.z, quat.w)
00198         self._current_pose.heading = rot.GetRPY()[2]
00199         
00200 
00201 if __name__ == '__main__':
00202     rospy.init_node('square')
00203     square = Square("/cmd_vel","/odom")
00204     rospy.spin()


kobuki_testsuite
Author(s): Jorge Santos Simon
autogenerated on Mon Oct 6 2014 01:33:05