ubuntu 18.04 melodic roslaunch :七步使用roslaunch控制两个终端机器人

1,切换目录：

$ roscd beginner_tutorials

2,新建launch子目录：

$ mkdir launch

3，进入子目录：

$  cd launch

4，新建launch文件

$ gedit turtlemimic.launch

5，复制下面源码到turtlemimic.launch，然后保存并退出：

 
   
 

 
   
 

 
   
   
 

6，运行roslaunch：

$ roslaunch beginner_tutorials turtlemimic.launch

uu@uu-HP-EliteBook-6930P-Notebook-PC:~$ roscd beginner_tutorials
uu@uu-HP-EliteBook-6930P-Notebook-PC:~/catkin_ws/src/beginner_tutorials$ mkdir launch
uu@uu-HP-EliteBook-6930P-Notebook-PC:~/catkin_ws/src/beginner_tutorials$ ls
CMakeLists.txt  include  launch  package.xml  src
uu@uu-HP-EliteBook-6930P-Notebook-PC:~/catkin_ws/src/beginner_tutorials$  cd launch
uu@uu-HP-EliteBook-6930P-Notebook-PC:~/catkin_ws/src/beginner_tutorials/launch$

uu@uu-HP-EliteBook-6930P-Notebook-PC:~/catkin_ws/src/beginner_tutorials/launch$ gedit turtlemimic.launch

uu@uu-HP-EliteBook-6930P-Notebook-PC:~/catkin_ws/src/beginner_tutorials/launch$ uu@uu-HP-EliteBook-6930P-Notebook-PC:~/catkin_ws/src/beginner_tutorials/launch$ roslaunch beginner_tutorials turtlemimic.launch
... logging to /home/uu/.ros/log/f0cf7f2e-a2cd-11e8-90ab-00216a949182/roslaunch-uu-HP-EliteBook-6930P-Notebook-PC-7213.log
Checking log directory for disk usage. This may take awhile.
Press Ctrl-C to interrupt
Done checking log file disk usage. Usage is <1GB.

started roslaunch server http://uu-HP-EliteBook-6930P-Notebook-PC:33327/

SUMMARY
========

PARAMETERS
 * /rosdistro: melodic
 * /rosversion: 1.14.2

NODES
  /
    mimic (turtlesim/mimic)
  /turtlesim1/
    sim (turtlesim/turtlesim_node)
  /turtlesim2/
    sim (turtlesim/turtlesim_node)

auto-starting new master
process[master]: started with pid [7223]
ROS_MASTER_URI=http://localhost:11311

setting /run_id to f0cf7f2e-a2cd-11e8-90ab-00216a949182
process[rosout-1]: started with pid [7234]
started core service [/rosout]
process[turtlesim1/sim-2]: started with pid [7241]
process[turtlesim2/sim-3]: started with pid [7242]
process[mimic-4]: started with pid [7243]

7,打开新终端，发布运动会话：

$  rostopic pub /turtlesim1/turtle1/cmd_vel geometry_msgs/Twist -r 1 -- '[2.0, 0.0, 0.0]' '[0.0, 0.0, -1.8]'