Hello, I am using ros_arduino_bridge to control my car. But when I use it in the Ubuntu 18.04 melodic version, it works. When I migrate it to Ubuntu 20 noetic version, it doesn't work. It shows some connection error as following. I have checked my baudrate is 57600 and my device is connected correctly at ttyACM0. Can someone tell me how to fix it? The file I just modified something like (because of python version in different ROS verison)

import thread

to

import _thread

and

print " "

to

print(" ")

> SUMMARY

PARAMETERS * /arduino/accel_limit: 0.05 * /arduino/angular_scale_correction: 1 * /arduino/base_controller_rate: 10 * /arduino/base_controller_timeout: 0.5 * /arduino/base_frame: base_footprint * /arduino/baud: 57600 * /arduino/debugPID: False * /arduino/encoder_resolution: 64 * /arduino/firstWheel_Kd: 18 * /arduino/firstWheel_Ki: 0 * /arduino/firstWheel_Ko: 50 * /arduino/firstWheel_Kp: 20 * /arduino/gear_reduction: 90.0 * /arduino/linear_scale_correction: 1 * /arduino/motors_reversed: True * /arduino/port: /dev/ttyACM0 * /arduino/rate: 50 * /arduino/secondWheel_Kd: 18 * /arduino/secondWheel_Ki: 0 * /arduino/secondWheel_Ko: 50 * /arduino/secondWheel_Kp: 10 * /arduino/sensors/arduino_led/direction: output * /arduino/sensors/arduino_led/pin: 13 * /arduino/sensors/arduino_led/rate: 5 * /arduino/sensors/arduino_led/type: Digital * /arduino/sensorstate_rate: 10 * /arduino/thirdWheel_Kd: 12 * /arduino/thirdWheel_Ki: 0 * /arduino/thirdWheel_Ko: 50 * /arduino/thirdWheel_Kp: 20 * /arduino/timeout: 0.4 * /arduino/use_base_controller: True * /arduino/wheel_diameter: 0.09 * /arduino/wheel_track: 0.2969 * /rosdistro: noetic * /rosversion: 1.15.13

NODES / arduino (ros_arduino_python/arduino_node.py)

ROS_MASTER_URI=http://192.168.0.100:11311

process[arduino-1]: started with pid [6639] Connecting to Arduino on port /dev/ttyACM0 ... Exception executing command: b Exception executing command: b Serial Exception: (<class 'serial.serialutil.serialexception'="">, SerialException(), <traceback object="" at="" 0xffff94685d00="">) Traceback follows: Traceback (most recent call last): File "/home/ubuntu/catkin_ws/src/ros_arduino_bridge/ros_arduino_python/src/ros_arduino_python/arduino_driver.py", line 73, in connect raise SerialException serial.serialutil.SerialException Cannot connect to Arduino! [arduino-1] process has died [pid 6639, exit code 1, cmd /home/ubuntu/catkin_ws/src/ros_arduino_bridge/ros_arduino_python/nodes/arduino_node.py __name:=arduino __log:=/home/ubuntu/.ros/log/f7eea18e-4623-11ec-8ada-6724a98c7e0c/arduino-1.log]. log file: /home/ubuntu/.ros/log/f7eea18e-4623-11ec-8ada-6724a98c7e0c/arduino-1*.log all processes on machine have died, roslaunch will exit shutting down processing monitor... ... shutting down processing monitor complete done