Controlling the Ar.Drone with a Gamepad Controller

=Introduction= In this tutorial we will learn how to control the ardrone with a game pad controller('Logitech dual action'). <br>500px|gamepad controller

=Package needed= Open up a terminal and enter: <pre> roscd joy </pre>

if it does not take you to the folder named “joy”. Then make sure to download the stack “joystick_driver” stack.

=Create the necessary file=

Step 1:Open up a terminal and enter :

<pre> roscd drone_teleop </pre>

Step 2:

Go to the folder named “bin” and create a file called “gamepad.py”. Paste the following code in the file and save the file.

#!/usr/bin/env python import roslib; roslib.load_manifest('drone_teleop') import rospy import rosbag from geometry_msgs.msg import Twist from std_msgs.msg import Empty from std_msgs.msg import Float64 from turtlesim.msg import Velocity from turtlesim.msg import Pose from sensor_msgs.msg import Joy

import sys, select, termios, tty import time msg = “”“ Reading from the keyboard and Publishing to Twist!

————————–

up/down: move forward/backward left/right: move left/right w/s: increase/decrease altitude a/d: turn left/right 1 / 2: takeoff / land 4: reset (toggle emergency state) 3: toggle_cam_view(newly added) 6: HOVER (right side top trigger) q: QUIT Auto

anything else: stop

please don't have caps lock on. CTRL+c to quit ”“” #control portal for the user xpos=0 ypos=0 xdis=0 joy_axes=[0.0, 0.0, 0.0, 0.0, 0.0, 0.0] joy_buttons= [0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0] move_bindings = {

	68:('linear', 'y', 0.1), #left
	67:('linear', 'y', -0.1), #right
	65:('linear', 'x', 0.1), #forward
	66:('linear', 'x', -0.1), #back
	'w':('linear', 'z', 0.1),
	's':('linear', 'z', -0.1),
	'a':('angular', 'z', 1),
	'd':('angular', 'z', -1),
       }

def callback(RecMsg):

  
  global xpos #displacement from the bottom line to be followed
  global ypos		
  global xdis	
  xpos = RecMsg.linear
  ypos = RecMsg.angular
 
  global i

def callback1(laserp):

 
  global xdis	
  xdis=  laserp.x

def callback2(joystick_cmd):

global joy_axes
global joy_buttons
joy_axes = joystick_cmd.axes
joy_buttons=joystick_cmd.buttons

def turnleft():

  twist.angular.z=-1
  pub.publish(twist)	
  time.sleep(1)	
  twist.angular.z=0
  pub.publish(twist)

def turnright():

  hover()				
  twist.angular.z=1
  pub.publish(twist)	
  time.sleep(1)	
  twist.angular.z=0
  pub.publish(twist)

def getKey():

tty.setraw(sys.stdin.fileno())
select.select([sys.stdin], [], [], 0)
key = sys.stdin.read(1)
termios.tcsetattr(sys.stdin, termios.TCSADRAIN, settings)
return key

def hover():

twist.linear.x = 0; twist.linear.y = 0; twist.linear.z = 0
twist.angular.x = 0; twist.angular.y = 0; twist.angular.z = 0
pub.publish(twist)

def motion():

twist.linear.x = 0.1*joy_axes[5] #forward(+) and backward(-)(pitch) 
twist.linear.y = 0.1*joy_axes[2] #lateral movement::LEFT(1):RIGHT(-1)(ROLL)
twist.linear.z = 0.1*joy_axes[3] #altitude movement:UP(+):DOWN(-)
twist.angular.x = 0 
twist.angular.y = 0 
twist.angular.z = 0.1*joy_axes[4]#angular::left(+)::right(-)	
pub.publish(twist)

if name==“main”:

  	settings = termios.tcgetattr(sys.stdin)
print msg

auto = True
pub = rospy.Publisher('cmd_vel', Twist)
land_pub = rospy.Publisher('/ardrone/land', Empty)
reset_pub = rospy.Publisher('/ardrone/reset', Empty)
      toggle_pub=rospy.Publisher('/ardrone/togglecam', Empty)
takeoff_pub =rospy.Publisher('/ardrone/takeoff', Empty)
rospy.Subscriber('/drocanny/vanishing_points',Velocity,callback)
rospy.Subscriber('/drone/walldis',Pose,callback1)
rospy.Subscriber('/joy',Joy,callback2)
      twist = Twist()
rospy.init_node('drone_teleop')

try:
	while(True):
                      i=0
		
		#key = 	getKey()
                      buttonvalue=  joy_buttons
		if buttonvalue[1] == 1:
			land_pub.publish(Empty())
			time.sleep(0.25)
		if buttonvalue[3] == 1:
			reset_pub.publish(Empty())
			time.sleep(1.5)
			land_pub.publish(Empty())
			time.sleep(0.25)
		if buttonvalue[0] == 1:				
			takeoff_pub.publish(Empty())
			time.sleep(0.25)
		if buttonvalue[2] == 1:
	     		toggle_pub.publish(Empty())
			time.sleep(0.25)
		if buttonvalue[7]==1:
			time.sleep(0.25)
			while(True):
				#add code here for autonomous functionality of the ardrone
			        
                                          if(buttonvalue[7]==1):
					print 'quit'
					break		
			time.sleep(0.25)	
		if buttonvalue[5] == 1:
			hover()
		
		
		motion()
		
except Exception as e:
	print e
	print repr(e)

finally:
	twist = Twist()
	twist.linear.x = 0; twist.linear.y = 0; twist.linear.z = 0
	twist.angular.x = 0; twist.angular.y = 0; twist.angular.z = 0
	pub.publish(twist)

  		termios.tcsetattr(sys.stdin, termios.TCSADRAIN, settings)

</source> Step 3:

Go to the folder bin in drone_teleop and right lick on the file “gamepad.py” and in the permissions tab click the check box “Allow executing file as a program”.

=Mapping of the buttons=

500px|gamepad layout

Control information:

gamepad control manual: <pre> B1 / B2: takeoff / land B4: reset (toggle emergency state) B3: toggle_cam_view B6: Hover the drone B8: Toggle to autonomous mode Axis 5: Move forward and pitch (pitch) Axis 4: Rotate left and right (yaw) Axis 3: Move up and down(altitude control) Axis 2: Move towards left and right(roll) </pre>

=Testing with gamepad= Now enter the following commands in a separate terminal : <pre> roscore rosrun ardrone_brown ardrone_driver rosrun joy joy_node rosrun drone_teleop gamepad.py rosrun image_view image_view image:=/ardrone/image_raw </pre>

If everything goes well,you should be able to control the ardrone with joystick.

=Use of button 8=

The button 8 of the joystick is used for setting ardrone to autonomous mode. To come back out of the autonomous mode hit button 8 again. I will talk more about this in the tutorial “Making the ARDRONE to do line following”.

=ARDRONE controlled through the gamepad controller= This program was used in Indoor Aerial Robotics Competition 2012 conducted by Drexel University ,USA. Here is a video of that.