8.5.5 Понимание скрипта навигации
Прежде чем запускать тестирование навигации на реальном роботе, давайте удостоверимся, что мы понимаем код, который заставляет ее работать.
Ссылка на источник: nav_test.py
#!/usr/bin/env python
import rospy
import actionlib
from actionlib_msgs.msg import *
from geometry_msgs.msg import Pose, PoseWithCovarianceStamped, Point, Quaternion, Twist
from move_base_msgs.msg import MoveBaseAction, MoveBaseGoal
from random import sample
from math import pow, sqrt
class NavTest():
def __init__(self):
rospy.init_node('nav_test', anonymous=True)
rospy.on_shutdown(self.shutdown)
# How long in seconds should the robot pause at each location?
self.rest_time = rospy.get_param("~rest_time", 10)
# Are we running in the fake simulator?
self.fake_test = rospy.get_param("~fake_test", False)
# Goal state return values
goal_states = ['PENDING', 'ACTIVE', 'PREEMPTED',
'SUCCEEDED', 'ABORTED', 'REJECTED',
'PREEMPTING', 'RECALLING', 'RECALLED',
'LOST']
# Set up the goal locations. Poses are defined in the map frame.
# An easy way to find the pose coordinates is to point-and-click
# Nav Goals in RViz when running in the simulator.
# Pose coordinates are then displayed in the terminal
# that was used to launch RViz.
locations = dict()
locations['hall_foyer'] = Pose(Point(0.643, 4.720, 0.000), Quaternion(0.000, 0.000, 0.223, 0.975))
locations['hall_kitchen'] = Pose(Point(-1.994, 4.382, 0.000), Quaternion(0.000, 0.000, -0.670, 0.743))
locations['hall_bedroom'] = Pose(Point(-3.719, 4.401, 0.000), Quaternion(0.000, 0.000, 0.733, 0.680))
locations['living_room_1'] = Pose(Point(0.720, 2.229, 0.000), Quaternion(0.000, 0.000, 0.786, 0.618))
locations['living_room_2'] = Pose(Point(1.471, 1.007, 0.000), Quaternion(0.000, 0.000, 0.480, 0.877))
locations['dining_room_1'] = Pose(Point(-0.861, -0.019, 0.000), Quaternion(0.000, 0.000, 0.892, -0.451))
# 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")
# A variable to hold the initial pose of the robot to be set by
# the user in RViz
initial_pose = PoseWithCovarianceStamped()
# Variables to keep track of success rate, running time,
# and distance traveled
n_locations = len(locations)
n_goals = 0
n_successes = 0
i = n_locations
distance_traveled = 0
start_time = rospy.Time.now()
running_time = 0
location = ""
last_location = ""
# Get the initial pose from the user
rospy.loginfo("*** Click the 2D Pose Estimate button in RViz to set the robot's initial pose...")
rospy.wait_for_message('initialpose', PoseWithCovarianceStamped)
self.last_location = Pose()
rospy.Subscriber('initialpose', PoseWithCovarianceStamped, self.update_initial_pose)
# Make sure we have the initial pose
while initial_pose.header.stamp == "":
rospy.sleep(1)
rospy.loginfo("Starting navigation test")
# Begin the main loop and run through a sequence of locations
while not rospy.is_shutdown():
# If we've gone through the current sequence,
# start with a new random sequence
if i == n_locations:
i = 0
sequence = sample(locations, n_locations)
# Skip over first location if it is the same as
# the last location
if sequence[0] == last_location:
i = 1
# Get the next location in the current sequence
location = sequence[i]
# Keep track of the distance traveled.
# Use updated initial pose if available.
if initial_pose.header.stamp == "":
distance = sqrt(pow(locations[location].position.x -
locations[last_location].position.x, 2) +
pow(locations[location].position.y -
locations[last_location].position.y, 2))
else:
rospy.loginfo("Updating current pose.")
distance = sqrt(pow(locations[location].position.x -
initial_pose.pose.pose.position.x, 2) +
pow(locations[location].position.y -
initial_pose.pose.pose.position.y, 2))
initial_pose.header.stamp = ""
# Store the last location for distance calculations
last_location = location
# Increment the counters
i += 1
n_goals += 1
# Set up the next goal location
self.goal = MoveBaseGoal()
self.goal.target_pose.pose = locations[location]
self.goal.target_pose.header.frame_id = 'map'
self.goal.target_pose.header.stamp = rospy.Time.now()
# Let the user know where the robot is going next
rospy.loginfo("Going to: " + str(location))
# Start the robot toward the next location
self.move_base.send_goal(self.goal)
# Allow 5 minutes to get there
finished_within_time = self.move_base.wait_for_result(rospy.Duration(300))
# Check for success or failure
if not finished_within_time:
self.move_base.cancel_goal()
rospy.loginfo("Timed out achieving goal")
else:
state = self.move_base.get_state()
if state == GoalStatus.SUCCEEDED:
rospy.loginfo("Goal succeeded!")
n_successes += 1
distance_traveled += distance
rospy.loginfo("State:" + str(state))
else:
rospy.loginfo("Goal failed with error code: " + str(goal_states[state]))
# How long have we been running?
running_time = rospy.Time.now() - start_time
running_time = running_time.secs / 60.0
# Print a summary success/failure, distance traveled and time elapsed
rospy.loginfo("Success so far: " + str(n_successes) + "/" +
str(n_goals) + " = " +
str(100 * n_successes/n_goals) + "%")
rospy.loginfo("Running time: " + str(trunc(running_time, 1)) +
" min Distance: " + str(trunc(distance_traveled, 1)) + " m")
rospy.sleep(self.rest_time)
def update_initial_pose(self, initial_pose):
self.initial_pose = initial_pose
def shutdown(self):
rospy.loginfo("Stopping the robot...")
self.move_base.cancel_goal()
rospy.sleep(2)
self.cmd_vel_pub.publish(Twist())
rospy.sleep(1)
def trunc(f, n):
# Truncates/pads a float f to n decimal places without rounding
slen = len('%.*f' % (n, f))
return float(str(f)[:slen])
if __name__ == '__main__':
try:
NavTest()
rospy.spin()
except rospy.ROSInterruptException:
rospy.loginfo("AMCL navigation test finished.")Вот ключевые строки сценария и что они делают:
Установка количества секунд для паузы в каждом месте, прежде чем переходить к следующему. Если параметр fake_test имеет значение True, параметр rest_time игнорируется.
Приятно иметь удобно читаемую форму различных состояний цели MoveBaseAction.
Места для целей (позы) хранятся в виде словаря Python. Значения Point и Quaternion можно найти, нажав кнопку 2D Nav Goal в RViz и отметив значения, отображаемые в терминале, который использовался для запуска RViz. Затем скопируйте и вставьте эти значения в ваш скрипт.
Здесь мы подписываемся на initialpose, чтобы мы могли установить начальное местоположение и ориентацию робота на карте в начале тестирования. При запуске теста на реальном роботе начальная поза устанавливается пользователем в RViz. Для искусственного робота (fake_test = True) эта переменная игнорируется, так как искусственная локализация уже идеальна.
Запуск теста до тех пор, пока пользователь не прервет приложение.
Мы используем функцию Python sample () для генерации случайной последовательности целей из набора местоположений.
Наконец, мы устанавливаем целевое местоположение для следующего местоположения в последовательности и отправляем его на сервер move_base .
Previous8.5.4 Запуск тестирования навигации в симуляцииNext8.5.6 Запуск тестирования навигации на реальном роботе
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