ROS-DEBUG1: Run Roscore times error: Unable to contact my own server at ...

First, the problem description

An error occurred while running Roscore on Terminal: Unable to contact my own server at ..., such as:

Second, the solution

The above problem is caused by the ROS environment variable Ros_master_uri setting error, reset the variable.

Open the ~/.BASHRC file, add or modify environment variables ros_hostname and ros_master, and change to:

Export Ros_hostname=localhostexport ros_master_uri=http://localhost:11311

After you modify and save the ~/.BASHRC file, restart the file, and then run Roscore to run normally.

　　Attention:

1. Some blog posts suggest changing Ros_hostname and Ros_master_uri to:

Export ros_hostname= terminal computer name Export ros_master_uri=http://Terminal PC name: 11311

The terminal computer name is the part between @ and: on the terminal, which is the system Settings in Ubuntu. Device name in details:

　　Actually, the method is not feasible.

2. Some blog posts suggest changing the Ros_master_uri to:

Export ros_master_uri=http://Computer IP address: 11311

Where the computer's IP address can be entered in the terminal: Ifconfig for viewing, that is:

It is also not feasible to verify this method in practice.

ROS-DEBUG1: Run Roscore times error: Unable to contact my own server at ...