Exemplo n.º 1
0
    def __init__(self):
        # Give the node a name
        rospy.init_node('out_and_back', anonymous=False)

        # Set rospy to execute a shutdown function when exiting       
        rospy.on_shutdown(self.shutdown)

        # Publisher to control the robot's speed
        self.cmd_vel = rospy.Publisher('/cmd_vel', Twist, queue_size=5)
        
        # How fast will we update the robot's movement?
        rate = 20
        
        # Set the equivalent ROS rate variable
        r = rospy.Rate(rate)
        
        # Set the forward linear speed to 0.2 meters per second 
        linear_speed = 0.2
        
        # Set the travel distance in meters
        goal_distance = 1.0

        # Set the rotation speed in radians per second
        angular_speed = 1.0
        
        # Set the angular tolerance in degrees converted to radians
        angular_tolerance = radians(2.5)
        
        # Set the rotation angle to Pi radians (180 degrees)
        goal_angle = pi

        # Initialize the tf listener
        self.tf_listener = tf.TransformListener()
        
        # Give tf some time to fill its buffer
        rospy.sleep(2)
        
        # Set the odom frame
        self.odom_frame = '/odom'
        
        # Find out if the robot uses /base_link or /base_footprint
        try:
            self.tf_listener.waitForTransform(self.odom_frame, '/base_footprint', rospy.Time(), rospy.Duration(1.0))
            self.base_frame = '/base_footprint'
        except (tf.Exception, tf.ConnectivityException, tf.LookupException):
            try:
                self.tf_listener.waitForTransform(self.odom_frame, '/base_link', rospy.Time(), rospy.Duration(1.0))
                self.base_frame = '/base_link'
            except (tf.Exception, tf.ConnectivityException, tf.LookupException):
                rospy.loginfo("Cannot find transform between /odom and /base_link or /base_footprint")
                rospy.signal_shutdown("tf Exception")  
        
        # Initialize the position variable as a Point type
        position = Point()
            
        # Loop once for each leg of the trip
        for i in range(2):
            # Initialize the movement command
            move_cmd = Twist()
            
            # Set the movement command to forward motion
            move_cmd.linear.x = linear_speed
            
            # Get the starting position values     
            (position, rotation) = self.get_odom()
                        
            x_start = position.x
            y_start = position.y
            
            # Keep track of the distance traveled
            distance = 0
            
            # Enter the loop to move along a side
            while distance < goal_distance and not rospy.is_shutdown():
                # Publish the Twist message and sleep 1 cycle         
                self.cmd_vel.publish(move_cmd)
                
                r.sleep()
        
                # Get the current position
                (position, rotation) = self.get_odom()
                
                # Compute the Euclidean distance from the start
                distance = sqrt(pow((position.x - x_start), 2) + 
                                pow((position.y - y_start), 2))

            # Stop the robot before the rotation
            move_cmd = Twist()
            self.cmd_vel.publish(move_cmd)
            rospy.sleep(1)
            
            # Set the movement command to a rotation
            move_cmd.angular.z = angular_speed
            
            # Track the last angle measured
            last_angle = rotation
            
            # Track how far we have turned
            turn_angle = 0
            
            while abs(turn_angle + angular_tolerance) < abs(goal_angle) and not rospy.is_shutdown():
                # Publish the Twist message and sleep 1 cycle         
                self.cmd_vel.publish(move_cmd)
                r.sleep()
                
                # Get the current rotation
                (position, rotation) = self.get_odom()
                
                # Compute the amount of rotation since the last loop
                delta_angle = normalize_angle(rotation - last_angle)
                
                # Add to the running total
                turn_angle += delta_angle
                last_angle = rotation
                
            # Stop the robot before the next leg
            move_cmd = Twist()
            self.cmd_vel.publish(move_cmd)
            rospy.sleep(1)
            
        # Stop the robot for good
        self.cmd_vel.publish(Twist())
Exemplo n.º 2
0
    def __init__(self):
        # Give the node a name
        rospy.init_node('nav_square', anonymous=False)
        
        # Set rospy to execute a shutdown function when terminating the script
        rospy.on_shutdown(self.shutdown)

        # How fast will we check the odometry values?
        rate = 20
        
        # Set the equivalent ROS rate variable
        r = rospy.Rate(rate)
        
        # Set the parameters for the target square
        goal_distance = rospy.get_param("~goal_distance", 1.0)      # meters
        goal_angle = rospy.get_param("~goal_angle", radians(90))    # degrees converted to radians
        linear_speed = rospy.get_param("~linear_speed", 0.2)        # meters per second
        angular_speed = rospy.get_param("~angular_speed", 0.7)      # radians per second
        angular_tolerance = rospy.get_param("~angular_tolerance", radians(2)) # degrees to radians
        
        # Publisher to control the robot's speed
        self.cmd_vel = rospy.Publisher('/cmd_vel', Twist, queue_size=5)
         
        # The base frame is base_footprint for the TurtleBot but base_link for Pi Robot
        self.base_frame = rospy.get_param('~base_frame', '/base_link')

        # The odom frame is usually just /odom
        self.odom_frame = rospy.get_param('~odom_frame', '/odom')

        # Initialize the tf listener
        self.tf_listener = tf.TransformListener()
        
        # Give tf some time to fill its buffer
        rospy.sleep(2)
        
        # Set the odom frame
        self.odom_frame = '/odom'
        
        # Find out if the robot uses /base_link or /base_footprint
        try:
            self.tf_listener.waitForTransform(self.odom_frame, '/base_footprint', rospy.Time(), rospy.Duration(1.0))
            self.base_frame = '/base_footprint'
        except (tf.Exception, tf.ConnectivityException, tf.LookupException):
            try:
                self.tf_listener.waitForTransform(self.odom_frame, '/base_link', rospy.Time(), rospy.Duration(1.0))
                self.base_frame = '/base_link'
            except (tf.Exception, tf.ConnectivityException, tf.LookupException):
                rospy.loginfo("Cannot find transform between /odom and /base_link or /base_footprint")
                rospy.signal_shutdown("tf Exception")  
                
        # Initialize the position variable as a Point type
        position = Point()

        # Cycle through the four sides of the square
        for i in range(4):
            # Initialize the movement command
            move_cmd = Twist()
            
            # Set the movement command to forward motion
            move_cmd.linear.x = linear_speed
            
            # Get the starting position values     
            (position, rotation) = self.get_odom()
                        
            x_start = position.x
            y_start = position.y
            
            # Keep track of the distance traveled
            distance = 0
            
            # Enter the loop to move along a side
            while distance < goal_distance and not rospy.is_shutdown():
                # Publish the Twist message and sleep 1 cycle         
                self.cmd_vel.publish(move_cmd)
                
                r.sleep()
        
                # Get the current position
                (position, rotation) = self.get_odom()
                
                # Compute the Euclidean distance from the start
                distance = sqrt(pow((position.x - x_start), 2) + 
                                pow((position.y - y_start), 2))
                
            # Stop the robot before rotating
            move_cmd = Twist()
            self.cmd_vel.publish(move_cmd)
            rospy.sleep(1.0)
            
            # Set the movement command to a rotation
            move_cmd.angular.z = angular_speed
            
            # Track the last angle measured
            last_angle = rotation
            
            # Track how far we have turned
            turn_angle = 0
            
            # Begin the rotation
            while abs(turn_angle + angular_tolerance) < abs(goal_angle) and not rospy.is_shutdown():
                # Publish the Twist message and sleep 1 cycle         
                self.cmd_vel.publish(move_cmd)
                
                r.sleep()
                
                # Get the current rotation
                (position, rotation) = self.get_odom()
                
                # Compute the amount of rotation since the last lopp
                delta_angle = normalize_angle(rotation - last_angle)
                
                turn_angle += delta_angle
                last_angle = rotation

            move_cmd = Twist()
            self.cmd_vel.publish(move_cmd)
            rospy.sleep(1.0)
            
        # Stop the robot when we are done
        self.cmd_vel.publish(Twist())
Exemplo n.º 3
0
    def __init__(self):
        # Give the node a name
        rospy.init_node('calibrate_angular', anonymous=False)
        
        # Set rospy to execute a shutdown function when terminating the script
        rospy.on_shutdown(self.shutdown)
        
        # How fast will we check the odometry values?
        self.rate = 30
        r = rospy.Rate(self.rate)
        
        # The test angle is 360 degrees
        self.test_angle = radians(rospy.get_param('~test_angle', 360.0))

        self.speed = rospy.get_param('~speed', 0.7) # radians per second
        self.tolerance = rospy.get_param('tolerance', radians(5)) # degrees converted to radians
        self.odom_angular_scale_correction = rospy.get_param('~odom_angular_scale_correction', 1.0)
        self.start_test = rospy.get_param('~start_test', True)
        
        # Publisher to control the robot's speed
        self.cmd_vel = rospy.Publisher('/cmd_vel', Twist, queue_size=5)
        
        # Fire up the dynamic_reconfigure server
        dyn_server = Server(CalibrateAngularConfig, self.dynamic_reconfigure_callback)
        
        # Connect to the dynamic_reconfigure server
        dyn_client = dynamic_reconfigure.client.Client("calibrate_angular", timeout=60)
        
        # The base frame is base_footprint for the TurtleBot but base_link for Pi Robot
        self.base_frame = rospy.get_param('~base_frame', '/base_link')

        # The odom frame is usually just /odom
        self.odom_frame = rospy.get_param('~odom_frame', '/odom')

        # Initialize the tf listener
        self.tf_listener = tf.TransformListener()
        
        # Give tf some time to fill its buffer
        rospy.sleep(2)
        
        # Make sure we see the odom and base frames
        self.tf_listener.waitForTransform(self.odom_frame, self.base_frame, rospy.Time(), rospy.Duration(60.0))
            
        rospy.loginfo("Bring up rqt_reconfigure to control the test.")
        
        reverse = 1
        
        while not rospy.is_shutdown():
            # Execute the rotation

            if self.start_test:
                # Get the current rotation angle from tf
                self.odom_angle = self.get_odom_angle()
                
                last_angle = self.odom_angle
                turn_angle = 0
                
                # Alternate directions between tests
                reverse = -reverse
                angular_speed  = reverse * self.speed
                
                while abs(turn_angle) < abs(self.test_angle):
                    if rospy.is_shutdown():
                        return
                    move_cmd = Twist()
                    move_cmd.angular.z = angular_speed
                    self.cmd_vel.publish(move_cmd)
                    r.sleep()
                 
                    # Get the current rotation angle from tf                   
                    self.odom_angle = self.get_odom_angle()
                    
                    # Compute how far we have gone since the last measurement
                    delta_angle = self.odom_angular_scale_correction * normalize_angle(self.odom_angle - last_angle)
                    
                    # Add to our total angle so far
                    turn_angle += delta_angle
                    last_angle = self.odom_angle
                
                # Stop the robot
                self.cmd_vel.publish(Twist())
                
                # Update the status flag
                self.start_test = False
                params = {'start_test': False}
                dyn_client.update_configuration(params)
                
            rospy.sleep(0.5) 
                    
        # Stop the robot
        self.cmd_vel.publish(Twist())