roslaunch dynamixel

edit

Hi again, here i'm still got problem changing my friend's ros-files electric structure and i want to changed it to indigo. i've download and install the dynamixel driver by sudo apt-get install ros-indigo-dynamixel-controllers ros-indigo-dynamixel-driver ros-indigo-dynamixel-msgs ros-indigo-dynamixel-motor and connect RS232 (for TTL) to AX12+. Now i got this error when i write roslaunch <my_package> ZMP_dynamixel.launch:

core service [/rosout] found
process[dynamixel_controller/dynamixel_manager-1]: started with pid [7803]
process[dynamixel_controller/dynamixel_controller_spawner_ax12-2]: started with pid [7804]
[INFO] [WallTime: 1446118639.239715] dynamixel_ax12 controller_spawner: waiting for controller_manager skripsi_dynamixel to startup in /dynamixel_controller/ namespace...
Traceback (most recent call last):
File "/opt/ros/indigo/lib/dynamixel_controllers/controller_manager.py", line 245, in <module>
 manager = ControllerManager()
File "/opt/ros/indigo/lib/dynamixel_controllers/controller_manager.py", line 102, in __init__
 serial_proxy.connect()
File "/opt/ros/indigo/lib/python2.7/dist-packages/dynamixel_driver/dynamixel_serial_proxy.py", line 97, in connect
 self.dxl_io = dynamixel_io.DynamixelIO(self.port_name, self.baud_rate)
File "/opt/ros/indigo/lib/python2.7/dist-packages/dynamixel_driver/dynamixel_io.py", line 67, in __init__
 self.ser = serial.Serial(port)
File "/usr/lib/python2.7/dist-packages/serial/serialutil.py", line 261, in __init__
 self.open()
File "/usr/lib/python2.7/dist-packages/serial/serialposix.py", line 278, in open
 raise SerialException("could not open port %s: %s" % (self._port, msg))
serial.serialutil.SerialException: could not open port /dev/ttyUSB0: [Errno 13] Permission denied: '/dev/ttyUSB0'
================================================================================REQUIRED process [dynamixel_controller/dynamixel_manager-1] has died!
process has died [pid 7803, exit code 1, cmd /opt/ros/indigo/lib/dynamixel_controllers/controller_manager.py __name:=dynamixel_manager __log:=/home/adelleodel/.ros/log/8c82747c-7e1d-11e5-bae6-240a6416fc2f/dynamixel_controller-dynamixel_manager-1.log].
log file: /home/adelleodel/.ros/log/8c82747c-7e1d-11e5-bae6-240a6416fc2f/dynamixel_controller-dynamixel_manager-1*.log
Initiating shutdown!
================================================================================
[dynamixel_controller/dynamixel_controller_spawner_ax12-2] killing on exit
[dynamixel_controller/dynamixel_manager-1] killing on exit

what should i do now?