dynamixel_controller manager wrong package prefix
Hello, I'm working with the dynamixel MX-64AT servos. Using a Ubuntu 16.04 and ROS kinetic version 1.12.12 Up until now I had no problem to get them up and running. Then I switched computers and now I get an error message whenever I try to start the controller_manager. Weirdly this problem now also occurs on the computer that up until now I had never had any troubles with. Basically the error can be reproduced when following this tutorial : http://wiki.ros.org/dynamixel_control... I do have the baud rate and id set to the right values and also checked that the USB port has the correct read and write permissions. Also I read that it could be related to faulty cables, but I also changed all of them several times, so that shouldn't be the problem.
Whenever I try to execute roslaunch my_dynamixel_tutorial controller_manager.launch I get these error messages saying something about a invalid response and wrong prefix error.
1517479067.955998897 INFO [dynamixel_serial_proxy.py:158(__find_motors) [topics: /motor_states/pan_tilt_port, /rosout, /diagnostics] pan_tilt_port: Pinging motor IDs 1 through 25...
1517479070.048603057 ERROR [dynamixel_serial_proxy.py:187(__find_motors) [topics: /motor_states/pan_tilt_port, /rosout, /diagnostics] Exception thrown while getting attributes for motor 10 - Invalid response received from motor 10. Wrong packet prefix []
1517479070.175116062 ERROR [dynamixel_serial_proxy.py:187(__find_motors) [topics: /motor_states/pan_tilt_port, /rosout, /diagnostics] Exception thrown while getting attributes for motor 10 - Invalid response received from motor 10. Wrong packet prefix ['\xff']
1517479070.177623033 ERROR [dynamixel_serial_proxy.py:187(__find_motors) [topics: /motor_states/pan_tilt_port, /rosout, /diagnostics] Exception thrown while getting attributes for motor 10 - Invalid response received from motor 10. Wrong packet prefix ['\xff', '\n']
1517479070.194986104 ERROR [dynamixel_serial_proxy.py:187(__find_motors) [topics: /motor_states/pan_tilt_port, /rosout, /diagnostics] Exception thrown while getting attributes for motor 10 - Invalid response received from motor 10. Wrong packet prefix ['\xc0']
1517479070.321788072 ERROR [dynamixel_serial_proxy.py:187(__find_motors) [topics: /motor_states/pan_tilt_port, /rosout, /diagnostics] Exception thrown while getting attributes for motor 10 - Invalid response received from motor 10. Wrong packet prefix []
1517479070.340946912 ERROR [dynamixel_serial_proxy.py:187(__find_motors) [topics: /motor_states/pan_tilt_port, /rosout, /diagnostics] Exception thrown while getting attributes for motor 15 - Invalid response received from motor 15. Wrong packet prefix ['0']
1517479070.357222080 ERROR [dynamixel_serial_proxy.py:187(__find_motors) [topics: /motor_states/pan_tilt_port, /rosout, /diagnostics] Exception thrown while getting attributes for motor 15 - unsupported operand type(s) for <<: 'float' and 'int'
1517479070.504827976 INFO [dynamixel_serial_proxy.py:211(__find_motors) [topics: /motor_states/pan_tilt_port, /rosout, /diagnostics] pan_tilt_port: Found 1 motors - 1 MX-64 [15], initialization complete.
Weirdly enough, sometimes it will still recognize both motors and be able to work with them. To me it sounds a bit as if something with the communication is going wrong, but to be honest I can't figure out, where it's going wrong. I would appreciate any help.
Best Regards, B.
