class ROSControllerNode(object):
"""ROS interface for controlling ARDrone, using position controller"""
def __init__(self):
"""Initialize the ROSControllerNode class."""
self.model_name = 'ARDroneCarre'
# Publishers
self.pub_cmd_vel = rospy.Publisher('cmd_vel_RHC',
Twist,
queue_size=300)
# Subscribers
self.sub_vicon_data = rospy.Subscriber(
'/vicon/{0}/{0}'.format(self.model_name), TransformStamped,
self.process_vicon_data)
self.sub_des_pos = rospy.Subscriber('des_pos', String,
self.process_desired_position)
# Initialize messages for publishing
self.cmd_vel = Twist()
# Run the onboard controller at 200 Hz
self.onboard_loop_frequency = 200.
# Calling the position controller to pass the data
self.pos_class = PositionController()
# Run this ROS node at the onboard loop frequency
self.run_pub_cmd_vel = rospy.Timer(
rospy.Duration(1. / self.onboard_loop_frequency),
self.process_commands)
# Initialize time
self.nonunix_time = 0
self.old_time = rospy.get_time()
self.start_time = rospy.get_time()
self.dt = 0
# Initialize points
self.current_point = 1
self.num_points_old = 0
def process_commands(self, event):
"""Determine the motor speeds and and publishes these."""
# Calculate time step
current_time = rospy.get_time()
self.dt = current_time - self.old_time
# Get commands from the position controller
commands = self.pos_class.update_position_controller(self.dt)
[roll_command, pitch_command, yaw_rate_command,
climb_rate_command] = commands
# Set cmd_vel message values to commands
self.cmd_vel.linear.x = roll_command
self.cmd_vel.linear.y = pitch_command
self.cmd_vel.linear.z = climb_rate_command
self.cmd_vel.angular.z = yaw_rate_command
# Publish commands
self.pub_cmd_vel.publish(self.cmd_vel)
# Update timestamp
self.old_time = current_time
def process_vicon_data(self, vicon_data_msg):
self.pos_class.current_trans_x = vicon_data_msg.transform.translation.x
self.pos_class.current_trans_y = vicon_data_msg.transform.translation.y
self.pos_class.current_trans_z = vicon_data_msg.transform.translation.z
self.pos_class.current_rot_x = vicon_data_msg.transform.rotation.x
self.pos_class.current_rot_y = vicon_data_msg.transform.rotation.y
self.pos_class.current_rot_z = vicon_data_msg.transform.rotation.z
self.pos_class.current_rot_w = vicon_data_msg.transform.rotation.w
def process_desired_position(self, pos_msg):
# Get message containing desired trajectory coordinates from desired_positions
self.des_pos_msg = np.fromstring(pos_msg.data, dtype=float, sep=' ')
# Calculate total number of waypoints
num_points = self.des_pos_msg.size / 4
# Update number of waypoints
if num_points != self.num_points_old:
self.num_points_old = num_points
self.current_point = 0
# Convert 1x12 array into 3 arrays of 4 elements (x,y,z)
trajectory = np.reshape(self.des_pos_msg, (-1, 4))
self.pos_class.desired_x = trajectory[self.current_point - 1,
0] # x coordinates
self.pos_class.desired_y = trajectory[self.current_point - 1,
1] # y coordinates
self.pos_class.desired_z = trajectory[self.current_point - 1,
2] # z coordinates
self.nonunix_time += self.dt
# setting deviation tolerance, the higher tolerance, the faster the drone navigates
if ((
(self.pos_class.desired_x - 0.5) < self.pos_class.current_trans_x <
(self.pos_class.desired_x + 0.5))
and ((self.pos_class.desired_y - 0.5) <
self.pos_class.current_trans_y <
(self.pos_class.desired_y + 0.5))
and ((self.pos_class.desired_z - 0.5) <
self.pos_class.current_trans_z <
(self.pos_class.desired_z + 0.5))):
if self.current_point < num_points and self.nonunix_time >= 0.01:
self.current_point += 1
self.nonunix_time = 0
class ROSControllerNode(object):
"""ROS interface for controlling the Parrot ARDrone in the Vicon Lab."""
# write code here to define node publishers and subscribers
# publish to /cmd_vel topic
# subscribe to /vicon/ARDroneCarre/ARDroneCarre for position and attitude feedback
def __init__(self):
"""Initialize the ROSControllerNode class."""
# Publishers
"""
self.pub_cmd_vel = rospy.Publisher('cmd_vel',
Twist,
queue_size = 300)
"""
self.pub_cmd_vel = rospy.Publisher('cmd_vel_RHC',
Twist,
queue_size=300)
self.pubTakePic = rospy.Publisher('/ardrone/take_pic',
String,
queue_size=10)
# Subscribers
self.model_name = 'ARDroneCarre'
self.sub_vicon_data = rospy.Subscriber(
'/vicon/{0}/{0}'.format(self.model_name), TransformStamped,
self.update_vicon_data)
self.sub_des_pos = rospy.Subscriber('des_pos', String,
self.update_desired_position)
# Initialize messages for publishing
self.cmd_vel_msg = Twist()
# Run the onboard controller at 200 Hz
self.onboard_loop_frequency = 200.
# Calling the position controller to pass the data
self.pos_class = PositionController()
# Run this ROS node at the onboard loop frequency
self.run_pub_cmd_vel = rospy.Timer(
rospy.Duration(1. / self.onboard_loop_frequency),
self.update_roll_pitch_yaw)
self.current_point = 1
self.nonunix_time = 0
self.dt = 0
self.num_points_old = 3
self.pic_number = 1
# Keep time for differentiation and integration within the controller
self.old_time = rospy.get_time()
self.start_time = rospy.get_time()
def update_roll_pitch_yaw(self, event):
"""Determine the motor speeds and and publishes these."""
# Determine the time step for differentiation and integration
current_time = rospy.get_time()
self.dt = current_time - self.old_time
# Get the next set of postioning commands from the position controller
new_controls = self.pos_class.update_position_controller(self.dt)
# Rearranging the data for ease
[new_roll, new_pitch, new_yaw_rate, new_climb_rate] = new_controls
# Setting the cmd_vel msg values to the desired ones
self.cmd_vel_msg.linear.x = new_roll
self.cmd_vel_msg.linear.y = new_pitch
self.cmd_vel_msg.angular.z = new_yaw_rate
self.cmd_vel_msg.linear.z = new_climb_rate
# Publish the motor commands for the ardrone plugin
self.pub_cmd_vel.publish(self.cmd_vel_msg)
# Set the old time to the current for future time step calculations
self.old_time = current_time
def update_vicon_data(self, vicon_data_msg):
(self.pos_class.current_trans_x, self.pos_class.current_trans_y,
self.pos_class.current_trans_z) = (
vicon_data_msg.transform.translation.x,
vicon_data_msg.transform.translation.y,
vicon_data_msg.transform.translation.z)
(self.pos_class.current_rot_x, self.pos_class.current_rot_y,
self.pos_class.current_rot_z,
self.pos_class.current_rot_w) = (vicon_data_msg.transform.rotation.x,
vicon_data_msg.transform.rotation.y,
vicon_data_msg.transform.rotation.z,
vicon_data_msg.transform.rotation.w)
def update_desired_position(self, pos_msg):
self.des_pos_msg = np.fromstring(pos_msg.data, dtype=float, sep=' ')
num_points = self.des_pos_msg.size / 4
if num_points != self.num_points_old:
self.num_points_old = num_points
self.current_point = 1
trajectory = np.reshape(self.des_pos_msg, (-1, 4))
self.pos_class.desired_x = trajectory[self.current_point - 1, 0]
self.pos_class.desired_y = trajectory[self.current_point - 1, 1]
self.pos_class.desired_z = trajectory[self.current_point - 1, 2]
self.pos_class.desired_yaw = trajectory[self.current_point - 1, 3]
self.nonunix_time += self.dt
#---------------------------------------------------
# SCANNING PHASE.
#---------------------------------------------------
self.pubTakePic.publish("no")
#---------------------------------------------------
if (((self.pos_class.desired_x - 0.15) < self.pos_class.current_trans_x
< (self.pos_class.desired_x + 0.15))
and ((self.pos_class.desired_y - 0.15) <
self.pos_class.current_trans_y <
(self.pos_class.desired_y + 0.15))
and ((self.pos_class.desired_z - 0.05) <
self.pos_class.current_trans_z <
(self.pos_class.desired_z + 0.05)) and
((self.pos_class.desired_yaw - 0.25) < self.pos_class.current_yaw <
(self.pos_class.desired_yaw + 0.25))):
if self.current_point < num_points and self.nonunix_time >= 0.01:
self.current_point += 1
self.nonunix_time = 0
#---------------------------------------------------
# SCANNING PHASE.
#---------------------------------------------------
current_mission_time = int(self.start_time -
(rospy.get_time()))
file_name = str(round(self.pic_number)) + "_t" + str(
current_mission_time) + "_X" + str(
round(self.pos_class.current_trans_x, 2)) + "_Y" + str(
round(self.pos_class.current_trans_y, 2)
) + "_Z" + str(round(
self.pos_class.current_trans_z, 2)) + "_W" + str(
round(self.pos_class.current_yaw, 2)) + ".jpg"
self.pic_number = self.pic_number + 1
self.pubTakePic.publish(file_name)
