Hello,
I have gotten to the end of the prerequisite exam but the grading system has been hanging for a long time so it is unable to mark my last two python scripts and give me my final score. Please I need your help with this so I can obtain my certificate.
Hello @Yelaina ,
The problem is that your program (task2.py) never ends. After the desired robot movement is achieved, the program has to stop.
Hello @albertoezquerro,
Thank you. I have tried to get the program to end all morning but I keep getting confused on how i can automatically initialize the rospy.on_shutdown(). Please see my code below, thank you.
#! /usr/bin/env python
import rospy
from sensor_msgs.msg import LaserScan
from geometry_msgs.msg import Twist
class RobotMove(object):
def __init__(self):
rospy.init_node('Robot_move')
#self._topic_name = topic_name
self._laser_sub = rospy.Subscriber('/kobuki/laser/scan', LaserScan, self.callback)
self._laser_scan = LaserScan()
self._cmd_pub = rospy.Publisher('/cmd_vel', Twist, queue_size=1)
self._twist_move = Twist()
rospy.spin()
def callback(self, msg):
self._laser_scan = msg
self.laser_scan_to_twist()
return self._laser_scan
def laser_scan_to_twist(self):
if self._laser_scan.ranges[0]<5:
self._twist_move.linear.x = 0.2
self._twist_move.angular.z = 0
self._cmd_pub.publish(self._twist_move)
if self._laser_scan.ranges[360]<=1.7:
self._twist_move.linear.x = 0.0
self._twist_move.angular.z = -2.5
self._cmd_pub.publish(self._twist_move)
if self._laser_scan.ranges[360]>7:
self._twist_move.linear.x = 0.0
self._twist_move.angular.z = 0.0
self._cmd_pub.publish(self._twist_move)
else:
pass
def shutdownhook():
# works better than the rospy.is_shut_down()
global ctrl_c
print "shutdown time!"
ctrl_c = True
rospy.on_shutdown(shutdownhook)
if name == ‘main’:
robotmove_object = RobotMove()
rate = rospy.Rate(2)
ctrl_c = False
while not ctrl_c:
data = robotmove_object.laser_scan_to_twist()
rospy.loginfo(data)
rate.sleep()