ROS over three Machines via Ethernet

asked 2016-04-05 08:30:30 -0500

jdiep gravatar image

updated 2016-04-05 10:43:29 -0500

Hello all,

Can somebody help me with this problem?

I am trying to connect three machines running ROS. The master device is an Intel NUC. It is connected via Ethernet with a laptop and via Ethernet-USB2.0 adapter with an UDOO mainboard. I followed the Multiple Machines tutorial and I was able to achieve a connection to each slave device separately. Nevertheless, I was not able to build up the ROS network over three machines simultaneously, i.e. I cannot see the published topics of my UDOO on my laptop and vice versa.

ROS_MASTER_URI is set to http://scubo-nuc:11311 on each device and the ROS_IP are set as follows: NUC (10.0.0.1), Laptop (10.0.0.2) and UDOO (10.0.0.3). I wrote a script with the export commands and run them on each machine.

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Comments

How are the ROS_IP's and ROS_MASTER_URI's set on the three devices?

NEngelhard gravatar imageNEngelhard ( 2016-04-05 10:06:20 -0500 )edit

This is probably a networking issue, as @NEngelhard is implying.

gvdhoorn gravatar imagegvdhoorn ( 2016-04-05 10:13:17 -0500 )edit
1

What happens if you do a "rostopic list" one each of the devices? [You can also edit your question with the new information so that it does not get lost in the comments]

NEngelhard gravatar imageNEngelhard ( 2016-04-05 10:40:21 -0500 )edit

Try to do a ping scubo-nuc on both of your 'slaves'. If you have no working DNS (ie the slaves can resolve the name to its IP), 3-way communication isn't going to work.

gvdhoorn gravatar imagegvdhoorn ( 2016-04-05 10:44:43 -0500 )edit

@NEngelhard: Thank you for the tip. rostopic list only works on one slave device at once. The problem lies in the connection. I checked it with ping scubo-nuc and get following result 64 bytes from 10.0.0.2: icmp_seq=.. ttl=64 time=....

jdiep gravatar imagejdiep ( 2016-04-05 10:58:36 -0500 )edit

@NEngelhard: But at the moment I connect the second slave device to the master this first connection gets lost ... Destination Host Unreachable

jdiep gravatar imagejdiep ( 2016-04-05 10:59:16 -0500 )edit

@jdiep: that sounds like an IP conflict. Make sure the IPs of all involved hosts are actually unique.

gvdhoorn gravatar imagegvdhoorn ( 2016-04-05 13:11:02 -0500 )edit

Do I have to set two different IP adresses for the master device, since it is connected to two slaves? Until now I set the IPs following: Laptop (10.0.0.2) connect with NUC (10.0.0.1), NUC (10.0.0.1) connects with UDOO (10.0.0.3)

jdiep gravatar imagejdiep ( 2016-04-06 13:39:23 -0500 )edit