Summary of ROS master-slave communication experience

1 Generally speaking , As long as both sides are under the same network segment , Even if nothing is done ,ping other party IP Fine ping through , therefore , If ping Different from each other's computers , First check the network segment settings , Router settings, etc .

2 Both master and slave need to be in hosts Set the other party's IP And the name , It should be noted that , The name set here must match the real name of the other computer （ After opening the terminal @ The name after the symbol ） Exactly the same . After completion, at the terminal ping The name of the other party's computer you just wrote , If it works ping through , Transfer to 3 Step ; otherwise , Transfer to 1 Step .

3 stay bashrc Set in ROS_MASTER_URI, The host is designated as itself, that is localhosts, Set the slave to the name of the host . Transfer to 4 Step .

4 Update complete hosts and bashrc after , need source Look at these two files , Or enter it manually in the terminal source Two file commands , Or put source Command write in bashrc in , Then every time you update bashrc Then open the new terminal . Here I suggest using the latter . Transfer to 5 Step to check whether the step is successful . Transfer to 5 Step .

5 Verify that the settings are successful , First start on the host roscore, Then check on the slave rostopic list, If you can see two normally ROS The news of , It means that the slave has been found ROS master. If the master or slave has any computer alarm “ROS_MASTER_URI[ Address ]is not set to XXXX”, Transfer to 3 Step .

6 The host starts the tortoise routine , The slave starts the keyboard control node , Observe whether the slave can be used to control the master turtle routine . If you can , Exchange master-slave nodes , Repeat the above steps . If both cannot be controlled or only one side can be controlled , Transfer to 7 Step .

7 Please check carefully /etc/hosts The name of the other party's computer in . After our experimental verification ： you are here hosts The name given to each other's computer in , Determines whether you can receive the other party's topic news . in other words , If you write in hosts The name of the computer in does not match the real name of the other computer , You can still send to each other normally topic, But you can't listen to what the other party sent topic.

Empathy , If we give two computers the same name , Then both computers cannot communicate normally . in consideration of linux It's troublesome for the thief to change the name of the system , Change it. It's easy to change it. It's not complete , So it is recommended to reinstall the system on one of the computers .

2022.7.14 In the morning In the mobile building laboratory