Foreword

Previous chapter has completed the simulation operation and navigation turtlebot3 slam, and this section will be script-controlled turtlebot3 navigate back and forth between multiple points. Project link: Download

Implementation process

Startup environment map

roslaunch turtlebot3_gazebo turtlebot3_world.launch

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Using the previous chapter talked about navigation maps built and open rviz visualization

roslaunch turtlebot3_navigation turtlebot3_navigation.launch map_file:=$HOME/map.yaml

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Using a modified 2D pose Estimate position

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Location on a mouse click on the map is your initial position, that is, the arrow points toward your initial robot.
Can be modified as shown below:

Ready to work

Create a multi-point navigation script

cd ~/wanderbot_ws/src/wanderbot/src
vi patrol.py

patrol.py: multi-point navigation script

#!/usr/bin/env python
 
import rospy
import actionlib
 
from move_base_msgs.msg import MoveBaseAction, MoveBaseGoal
 
 
waypoints = [  # <1>
    [(1.522, 0.444, 0.0), (0.0, 0.0, -0.519, 0.85)],
    [(-2.0432, -0.439, 0.0), (0.0, 0.0, -0.559, 0.82902)]
]
 
 
def goal_pose(pose):  # <2>
    goal_pose = MoveBaseGoal()
    goal_pose.target_pose.header.frame_id = 'map'
    goal_pose.target_pose.pose.position.x = pose[0][0]
    goal_pose.target_pose.pose.position.y = pose[0][1]
    goal_pose.target_pose.pose.position.z = pose[0][2]
    goal_pose.target_pose.pose.orientation.x = pose[1][0]
    goal_pose.target_pose.pose.orientation.y = pose[1][1]
    goal_pose.target_pose.pose.orientation.z = pose[1][2]
    goal_pose.target_pose.pose.orientation.w = pose[1][3]
 
    return goal_pose
 
 
if __name__ == '__main__':
    rospy.init_node('patrol')
 
    client = actionlib.SimpleActionClient('move_base', MoveBaseAction)  # <3>
    client.wait_for_server()
     
    while True:
        for pose in waypoints:   # <4>
            print("goal:x=%f y=%f"%(pose[0][0],pose[0][1]))
            goal = goal_pose(pose)
            client.send_goal(goal)
            client.wait_for_result()

Determining the waypoint location

rostopic list

View All Topics name
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apparently topic navigation coordinates are amcl_pose.

AMCL: In ros, we use amcl package robot localization on the map. amcl nodes to achieve a series of probabilistic location algorithm, collectively referred to as adaptive Monte Carlo localization algorithms (Adaptive Monte Carlo Locatization).
Specifically, he uses sample_motion_model_odometry, beam_range_finder_model, likelihood_filed_range_finder_model, Augmented_MCL and KLD_Sampling_MCL algorithm.

So we monitor this topic, it was still used ros debugging tools: rostopic

rostopic echo amcl_pose -n 1

Print out the current coordinates:
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pose:
position:
x: -2.03239229723
y: -0.408803583203
z: 0.0
orientation:
x: 0.0
y: 0.0
z: -0.529167851235
w: 0.848517168488

Obviously this is what we want the coordinates.
Then rviz by just a few points navigation point
print position to reach the target again:

rostopic echo amcl_pose -n 1

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ok we know the initial coordinates and target coordinates:
Initial:
position:
X: -2.03239229723
Y: -0.408803583203
Z: 0.0
Orientation:
X: 0.0
Y: 0.0
Z: -0.529167851235
W: 0.848517168488
objectives:
position:
X: 1.76888229632
Y: .588761452838
z: 0.0
Orientation:
the X-: 0.0
the y-: 0.0
z: -0.459069601992
w: 0.888400304214
them write to our multi-point navigation script written inside.
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This section can be modified.
After modification exit, set permissions