rostopic echo doesn't return any data
So, kind of a weird problem.
I set up ROS on an RPi with a kinect. I am generating a map with slam_gmapping. It works - but it's terribly slow. So, I decided to off load the SLAM process to an actual PC that is much faster.
I did - and it seems to be working fine. However, on the raspberry pi I can no longer see the map. for instance rostopic echo /map never returns, which tells me nothing is being published.
However, on the PC I can echo the map just fine.
Likewise, I have depthimagetolaserscan running on the Rpi. On both the pi and the PC I can easily echo /scan.
It seems to be specific to running slam_gmapping on the PC that I can't echo the map on the Rpi.
What could cause that?
Asked by jgauthier on 2022-01-09 14:43:06 UTC
Answers
Please take a look at previous question:#q322394
The most common issue is: setting ROS_HOSTNAME or ROS_MASTER_URI to a hostname without a way for the machines to resolve the hostnames into IPs (or setting ROS_IP to a hostname, instead of an IP).
Asked by osilva on 2022-01-10 06:39:04 UTC
Comments
I'm using all IPs. But this doesn't make sense to me. On machine A (which is running roscore) I can echo all the topics except for the one published by machine B. On machine B, I can echo all topics.
Asked by jgauthier on 2022-01-10 11:31:04 UTC
do you use different namespaces? if so you have to add that namespace in front of the topic. If not I agree that the problem is mist likely with your ROS_HOSTNAME ROS_MASTER_URI ROS_IP setup.
Asked by crnewton on 2022-01-15 06:43:32 UTC
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