Turtlebot disconnects when additional /dev/ttyUSB port is active

turtlebot

asked 2011-07-30 14:26:49 -0600

Pi Robot
4046 ●134 ●158 ●192 http://www.pirobot.org/

updated 2011-07-31 05:46:05 -0600

Hello,

I am trying out the Turtlebot stack under Electric (beta). So far everything works great including the follower application. Next I want to control two Dynamixel AX-12 servos that I have attached to the Kinect for pan and tilt. The Create is on port /dev/ttyUSB1 and my USB2Dynamixel controller is on /dev/ttyUSB0 and I am using the dynamixel_motor package to control the servos.

When I launch the Turtlebot using the minimal.launch file, everything comes up fine on /dev/ttyUSB1. But as soon as I launch the dynamixel_motor controllers (which comes up fine on /dev/ttyUSB0), I get the following error in the Turtlebot launch window:

Failed to contact device with error: [Error reading from SCI port. Wrong data length.]. Please check that the Create is powered on and that the connector is plugged into the Create.[turtlebot_node-3] process has finished cleanly.
log file: /home/patrick/.ros/log/28a03a10-bb09-11e0-bde5-00271017076c/turtlebot_node-3*.log
respawning...
[turtlebot_node-3] restarting process
process[turtlebot_node-3]: started with pid [9174]

This block then just keeps repeating indefinitely.

Has anyone else experienced something similar?

Thanks! patrick

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Have you tried setting your udev rules to make the SCI port /dev/ttyUSB0 and your USB2Dynamixel controller /dev/ttyUSB1? I have a Logitech webcam running on /dev/ttyUSB1 with no problems.

Alaina ( 2011-07-31 07:02:17 -0600 )edit

Thanks Alaina--that did the trick! If you post your comment as an answer, I can accept it as the correct answer.

Pi Robot ( 2011-07-31 15:12:37 -0600 )edit

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answered 2011-07-31 17:01:38 -0600

Alaina
121 ●4 ●6 ●12 http://9thsense.com/

updated 2011-07-31 17:05:05 -0600

Have you tried setting your udev rules to make the SCI port /dev/ttyUSB0 and your USB2Dynamixel controller /dev/ttyUSB1? I have a Logitech webcam running on /dev/ttyUSB1 with no problems.

The Turtlebot software is looking for the Create on ttyUSB0. You can change that in the launch files, but I prefer to mess with less. :)

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Actually, I did set the Create port to /dev/ttyUSB1 in the launch file and it connected to that port fine but I still ran into the disconnect problem when the USB2Dynamixel is on port /dev/ttyUSB0. So I am wondering if there might be some other place in the Turtlebot code where USB0 is hard coded. In any event, your udev solution works fine for now. Thanks!

Pi Robot ( 2011-08-01 01:00:05 -0600 )edit

Could one of you guys post here the udev files you created? Thanks!

t.pimentel ( 2013-05-28 04:25:49 -0600 )edit

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answered 2012-01-12 02:27:05 -0600

Roman Burdakov

131 ●9 ●13 ●21

I just got same problem - iCreate is no longer accessible on /dev/ttyUSB0. Could you please provide your solution on how you have change launch configuration? I've search settings for USB in minimal_launch of the turtlebot_bringup stack but didn't find anything useful.

Another question - is it better to change launch configuration of the turtlebot or change port settings in ubuntu itself? Let's say somewhere in other packages there would be hard coded port ttyUSB0 but I had changed it on 1, so I would create new problem for myself. What would be the best solution in this case? Thanks.

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Definitively udev rules is the good way, as you can fix port names. You can also provide meaningful names to your ports, as /dev/turtlebot, /dev/aduino, etc...

jorge ( 2013-05-28 14:30:50 -0600 )edit

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Turtlebot disconnects when additional /dev/ttyUSB port is active

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