ROS tools in Linux by command line

ROS tools in Linux

1. open Turtlesim

roscore # start the ROS Master

rosrun turtlesim turtlesim_node # start the turtlesim

rosrun turtlesim turtle_teleop_key # start turtle control node

2. rqt_graph

rqt_graph

• /turtlesim node is a simple simulator for teaching ROS concepts.
• teleop_turtle node
• /turtle1/cmd_vel topic

3. rosnode list

rosnode list # show the current nodes

3. rosnode info

rosnode info somenode # check somenode's information

4. rostopic list

rostopic list # show the current topic

5. rostopic pub

rostopic pub /turtle1/cmd_vel # 

click tab button twice

rostopic pub /turtle1/cmd_vel geometry_msgs/Twist "linear: 
  x: 0.0
  y: 0.0
  z: 0.0
angular:
  x: 0.0
  y: 0.0
  z: 0.0" 

• we can find turtle move
• but only move once
• it is because pub instruction only publish one time

rostopic pub -r 10 /turtle1/cmd_vel geometry_msgs/Twist "linear:
  x: 1.0
  y: 0.0
  z: 0.0
angular:
  x: 0.0
  y: 0.0
  z: 0.0"

add -r 10 after pub,

• -r means rate,
• 10 means 10 times per second

6. rosmsg show

rosmsg show geometry_msgs/Twist

7. rosservice list

rosservice list # show all service

8. rosservice call

rosservice call /spawn 

click tab for 2 times

rosservice call /spawn "x: 2.0
y: 2.0
theta: 0.0
name: 'turtle2'" 

we create another turtle

now we call rostopic list again, we can find we have turtle2 here

9. rosbag record

rosbag record -a -O cmd_record # record the data into cmd_record file

• we can find a new file under current folder has been created
• named cmd_record.bag

rosbag play cmd_record.bag # play the data(the cmd_record file)