Frequently Asked Questions

Can I upgrade VIPER using apt upgrade command?

This is not recommended and by doing so you may lose the warranty.

Contact support if you have not found a solution to your problem in this documentation.

How do I check VIPER logs?

Connect to your VIPER via ssh:

ssh <VIPER_IP>

Depending on the app/issue run one of the following.

App service status:

systemctl status cvm-webconfig
systemctl status cvm-stereo
systemctl status cvm-follow-me
systemctl status cvm-follow-aruco
systemctl status cvm-obstactle-detector

App logs:

journalctl -u cvm-webconfig
journalctl -u cvm-stereo
journalctl -u cvm-follow-me
journalctl -u cvm-follow-aruco
journalctl -u cvm-obstactle-detector

How do I fix the “unable to communicate with master!” error?

Solution:

Is your VIPER running and active? If no, please turn it on.

Is your ROS_MASTER_URI set correctly? If no, please set the ROS_MASTER_URI to the location of your VIPER.

Can you contact the address specified in the ROS_MASTER_URI?

echo $ROS_MASTER_URI
http://<VIPER_IP>:11311
ping <VIPER_IP>
ping: unknown host <VIPER_IP>

If you get the “unknown host” error, please check your network settings or change the ROS_MASTER_URI to a resolvable address.

How do I find VIPER IP address?

Please refer to VIPER Discovery.

How do I synchronize VIPER’s clock to the clock of a robot?

On your robot’s PC (Ubuntu OS) install and enable Chrony:

sudo apt-get install chrony
sudo systemctl start chrony
sudo systemctl enable chrony

Set up Chrony NTP server on the robot’s PC

sudo vim /etc/chrony/chrony.conf

and paste this:

driftfile /var/lib/chrony/drift
local stratum 10
manual
allow 10.42.0.0/24

Note

Change network IP (10.42.0.0 in this example) to the IP of your network

Then reboot your robot’s PC or restart the Chrony service

sudo systemctl restart chrony

Note

The configuration will run automatically when you power on the PC next time. This is required only once.

On the VIPER you just have to set ROS MASTER of the configured robot PC. The two computers should synchronize after reboot. Also, there is a possibility to force synchronization by pressing Force sync in System time on the VIPER’s web page.

How do I fix md5sum error while running a demo application?

There is an issue with some ROS package version, therefore we need to get the newest version.

Connect to your VIPER via ssh:

ssh <VIPER_IP>

and run the following commands:

sudo cp /opt/rubedo/cvm/cvm-debs-update.bash  /home/ubuntu/cvm-debs-update_cp.bash
sudo /home/ubuntu/cvm-debs-update_cp.bash

How do fix ‘Could not load library (Poco exception = libopencv_calib3d3.so.3.3: cannot open shared object file: No such file or directory’?

Connect to your VIPER via ssh:

ssh <VIPER_IP>

and run the following commands:

sudo apt-get install ros-kinetic-opencv3=3.3.1-0xenial