Hello,
We are currently working with the Magni Silver running on Ubuntu version 16.04.6 LTS and have run into what we believe to be networking issues on the Raspberry Pi while it is connected in client mode to our current wireless network. The problem we are seeing is that we are unable to teleop and move the magni base even though the velocity commands are being published to the ros topic cmd_vel. We have attempted to use a newly restored Pi which initially works to teleop the Magni, however after some time, it too is unable to successfully move the robot. We have verified that the wheels lock when the magni is powered on, so we do not think that it is a problem with the motors. Our own ROS nodes are also able to operate properly on the Pi. Since this problem has newly been seen on multiple magni bases as well as multiple Raspberry Pi’s, we believe that this is a networking issue. Any advice would be very appreciated.
Thank you.
So when you say you’re publishing the teleop commands to cmd_vel is that from the workstation directly, or through ssh on the robot?
If it’s the first one and the second one works then yeah it’s bound to be a networking thing, otherwise it’s something to do with the motor node.
ISSUE RESOLVED:
We were seeing this issue only when attempting to teleop from the workstation with the Magni properly set as the ROS master. After a clean image, we could initially move the robot when SSH’ed into the Pi, but were unable to control the robot or observe data from the relevant Magni ROS topics such as odom from a separate workstation.
To resolve this, we edited the etc/hosts file on the workstation so that it includes the IP address and hostnames for the Magni that we wish to be communicating with. After doing this, we were able to view /odom data as well as teleop the Magni from our workstation.
Because of this forum post and others we have realized we need to do a better job of informing customers of the things that must be setup for a workstation to be able to take part in issuing of commands or viewing topics or runing graphics programs like RVIZ.
With that in mind the end of our ‘Connecting a workstation’ page seen at the top page of our learn.ubiquityrobotics.com doc pages now clearly indicates the setup required for a laptop to be controlling the magni.
Refer to: https://learn.ubiquityrobotics.com/connecting