使用move_base导航 ---13

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我们现在准备用move_base简单的移动机器人记住，一个“pose”在ros的意思是一个位置和方向。

1.首先启动turtlebot机器人。

roslaunch rbx1_bringup fake_turtlebot.launch

2.在另一个终端运行：

roslaunch rbx1_nav fake_move_base_blank_map.launch

3.打开rviz视图查看机器人。

rosrun rviz rviz -d `rospack find rbx1_nav`/nav.rviz

4.运行move_base_square.py脚本移动机器人。

rosrun rbx1_nav move_base_square.py

5.rviz视图如下：

6.rqt_graph节点框图如下：

7.节点move_base_square.py代码如下：

#!/usr/bin/env python

import rospy
import actionlib
from actionlib_msgs.msg import *
from geometry_msgs.msg import Pose, Point, Quaternion, Twist
from move_base_msgs.msg import MoveBaseAction, MoveBaseGoal
from tf.transformations import quaternion_from_euler
from visualization_msgs.msg import Marker
from math import radians, pi

class MoveBaseSquare():
    def __init__(self):
        rospy.init_node('nav_test', anonymous=False)
        
        rospy.on_shutdown(self.shutdown)
        
        # How big is the square we want the robot to navigate?
        square_size = rospy.get_param("~square_size", 1.0) # meters
        
        # Create a list to hold the target quaternions (orientations)
        quaternions = list()
        
        # First define the corner orientations as Euler angles
        euler_angles = (pi/2, pi, 3*pi/2, 0)
        
        # Then convert the angles to quaternions
        for angle in euler_angles:
            q_angle = quaternion_from_euler(0, 0, angle, axes='sxyz')
            q = Quaternion(*q_angle)
            quaternions.append(q)
        
        # Create a list to hold the waypoint poses
        waypoints = list()
        
        # Append each of the four waypoints to the list.  Each waypoint
        # is a pose consisting of a position and orientation in the map frame.
        waypoints.append(Pose(Point(square_size, 0.0, 0.0), quaternions[0]))
        waypoints.append(Pose(Point(square_size, square_size, 0.0), quaternions[1]))
        waypoints.append(Pose(Point(0.0, square_size, 0.0), quaternions[2]))
        waypoints.append(Pose(Point(0.0, 0.0, 0.0), quaternions[3]))
        
        # Initialize the visualization markers for RViz
        self.init_markers()
        
        # Set a visualization marker at each waypoint        
        for waypoint in waypoints:           
            p = Point()
            p = waypoint.position
            self.markers.points.append(p)
            
        # Publisher to manually control the robot (e.g. to stop it, queue_size=5)
        self.cmd_vel_pub = rospy.Publisher('cmd_vel', Twist, queue_size=5)
        
        # Subscribe to the move_base action server
        self.move_base = actionlib.SimpleActionClient("move_base", MoveBaseAction)
        
        rospy.loginfo("Waiting for move_base action server...")
        
        # Wait 60 seconds for the action server to become available
        self.move_base.wait_for_server(rospy.Duration(60))
        
        rospy.loginfo("Connected to move base server")
        rospy.loginfo("Starting navigation test")
        
        # Initialize a counter to track waypoints
        i = 0
        
        # Cycle through the four waypoints
        while i < 4 and not rospy.is_shutdown():
            # Update the marker display
            self.marker_pub.publish(self.markers)
            
            # Intialize the waypoint goal
            goal = MoveBaseGoal()
            
            # Use the map frame to define goal poses
            goal.target_pose.header.frame_id = 'map'
            
            # Set the time stamp to "now"
            goal.target_pose.header.stamp = rospy.Time.now()
            
            # Set the goal pose to the i-th waypoint
            goal.target_pose.pose = waypoints[i]
            
            # Start the robot moving toward the goal
            self.move(goal)
            
            i += 1
        
    def move(self, goal):
            # Send the goal pose to the MoveBaseAction server
            self.move_base.send_goal(goal)
            
            # Allow 1 minute to get there
            finished_within_time = self.move_base.wait_for_result(rospy.Duration(60)) 
            
            # If we don't get there in time, abort the goal
            if not finished_within_time:
                self.move_base.cancel_goal()
                rospy.loginfo("Timed out achieving goal")
            else:
                # We made it!
                state = self.move_base.get_state()
                if state == GoalStatus.SUCCEEDED:
                    rospy.loginfo("Goal succeeded!")
                    
    def init_markers(self):
        # Set up our waypoint markers
        marker_scale = 0.2
        marker_lifetime = 0 # 0 is forever
        marker_ns = 'waypoints'
        marker_id = 0
        marker_color = {'r': 1.0, 'g': 0.7, 'b': 1.0, 'a': 1.0}
        
        # Define a marker publisher.
        self.marker_pub = rospy.Publisher('waypoint_markers', Marker, queue_size=5)
        
        # Initialize the marker points list.
        self.markers = Marker()
        self.markers.ns = marker_ns
        self.markers.id = marker_id
        self.markers.type = Marker.CUBE_LIST
        self.markers.action = Marker.ADD
        self.markers.lifetime = rospy.Duration(marker_lifetime)
        self.markers.scale.x = marker_scale
        self.markers.scale.y = marker_scale
        self.markers.color.r = marker_color['r']
        self.markers.color.g = marker_color['g']
        self.markers.color.b = marker_color['b']
        self.markers.color.a = marker_color['a']
        
        self.markers.header.frame_id = 'odom'
        self.markers.header.stamp = rospy.Time.now()
        self.markers.points = list()

    def shutdown(self):
        rospy.loginfo("Stopping the robot...")
        # Cancel any active goals
        self.move_base.cancel_goal()
        rospy.sleep(2)
        # Stop the robot
        self.cmd_vel_pub.publish(Twist())
        rospy.sleep(1)

if __name__ == '__main__':
    try:
        MoveBaseSquare()
    except rospy.ROSInterruptException:
        rospy.loginfo("Navigation test finished.")