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en:ros:turtlesim [2021/03/29 10:45] – [Command line] momalaen:ros:turtlesim [Unknown date] (current) – external edit (Unknown date) 127.0.0.1
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 ====== ROS Tools ====== ====== ROS Tools ======
  
-Using simulations is a good way to learn ROS without having to own a physical robot. In this chapter we just use a 2D simulation called Turtlesim.This tutorial will give you a good idea of what ROS tools can do for you.+Using simulations is a good way to learn ROS without having to own a physical robot. In this chapter we just use a 2D simulation called Turtlesim. This tutorial will give you a good idea of what ROS tools can do for you.
 First, run //roscore//: First, run //roscore//:
  
    $ roscore    $ roscore
  
-Run the launch file demo for turtlesim:+Run the launch file demo for Turtlesim:
  
    $ roslaunch turtle_tf turtle_tf_demo.launch    $ roslaunch turtle_tf turtle_tf_demo.launch
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 When the launch file is running, a simulation with a graphical user interface opens. When the launch file is running, a simulation with a graphical user interface opens.
  
-The launch file also contains a node that can be used to send keyboard movement messages to the robot. you need to click on the terminal that you opened the launch file and use arrow keys to move the turtlebot1. Then you can see that the second turtlebot will follow the first one.+The launch file also contains a node that can be used to send keyboard movement messages to the robot. you need to click on the terminal that you opened the launch file and use arrow keys to move the turtlebot1. Then you can see that the second turtle bot will follow the first one.
  
-{{ :en:ros:screenshot_from_2021-03-29_12-10-01.png?400 |}}+{{ :en:ros:screenshot_from_2021-03-29_12-10-01.png?300 |}}
  
 ===== RViz ===== ===== RViz =====
-Short for ROS Visualization. It’s a 3-dimensional visualization tool for ROS that helps to visualize what the robot seeing and doing. To run the RViz for the the turtlebot simulation there is a predefined configuration file that you can run it with the following command:+Short for ROS Visualization. It’s a 3-dimensional visualization tool for ROS that helps to visualize what the robot seeing and doing. To run the RViz for the turtlebot simulation there is a predefined configuration file that you can run with the following command:
  
   $ rosrun rviz rviz -d `rospack find turtle_tf`/rviz/turtle_rviz.rviz   $ rosrun rviz rviz -d `rospack find turtle_tf`/rviz/turtle_rviz.rviz
  
-As you can see there are three different transformation frame (tf) in the environment that each represents an element. The world is defined for the environment and turtle1 and turtle2 are for the robots. These transformation frames are useful for positioning and localization. +As you can see there are three different transformation frames (tf) in the environment that each represents an element. The world is defined for the environment and turtle1 and turtle2 are for the robots. These transformation frames are useful for positioning and localization. 
  
 {{ :en:ros:screenshot_from_2021-03-29_12-18-19.png?600 |}} {{ :en:ros:screenshot_from_2021-03-29_12-18-19.png?600 |}}
  
 ===== Rqt_graph ===== ===== Rqt_graph =====
 + 
 +ROS also comes with some graphical tools. //Rqt_graph// graphically shows which nodes communicate with each other. It is also possible to filter nodes and topics differently. //rqt_graph// allows you to save the graph in //pdf// format.
  
-Let's see how it works using the //rqt_graph// tool, which visualizes the relationships between nodes and themes:+run //rqt_graph//:
  
    $ rqt_graph    $ rqt_graph
-   + 
 +When the command is executed, the graphical user interface opens. Robots with complex tasks usually have many different nodes working on them that interact with a variety of topics. It is difficult to see the big picture from the command line and this is done using the //rqt_graph// program. Let's see how it works using the //rqt_graph// tool, which visualizes the relationships between nodes and themes. 
 +  
 {{ :en:ros:screenshot_from_2021-03-29_12-28-02.png?600 |}} {{ :en:ros:screenshot_from_2021-03-29_12-28-02.png?600 |}}
  
 Launching the command opens a graphical user interface. We see that the ///teleop// node reads the arrow keys and turns them into a robot motion. It is sent to ///turtle1/cmd_vel//, which is listened to by a robot simulation. By running the same nodes on different computers, we can control the robot from another computer. A similar configuration is often used to control real robots. Also, there are two broadcasters for the TFs, ///sim// node is publishing position in ///turtl1/pose// and ///turtle2/pose//. Launching the command opens a graphical user interface. We see that the ///teleop// node reads the arrow keys and turns them into a robot motion. It is sent to ///turtle1/cmd_vel//, which is listened to by a robot simulation. By running the same nodes on different computers, we can control the robot from another computer. A similar configuration is often used to control real robots. Also, there are two broadcasters for the TFs, ///sim// node is publishing position in ///turtl1/pose// and ///turtle2/pose//.
 +
 +Example of a graph on a more complex robot:
 +
 +{{ :et:ros:rqtslam.png?700 |}}
 +
  
 ===== Rqt_tf_tree ===== ===== Rqt_tf_tree =====
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 {{ :en:ros:screenshot_from_2021-03-29_13-08-13.png?600 |}} {{ :en:ros:screenshot_from_2021-03-29_13-08-13.png?600 |}}
  
-As can be seen in the gui, two //turtle1// and //turtle2// frames are connected to the world tf. There are two broadcasters for them that calculate their transformation and publish them relative to the world. +As can be seen in the GUI, two //turtle1// and //turtle2// frames are connected to the world tf. There are two broadcasters for them that calculate their transformation and publish them relative to the world. 
 ===== Command line ===== ===== Command line =====
  
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 ===== Rqt_plot ===== ===== Rqt_plot =====
  
-The //rqt_plot// tool is used to visualize the subject data over time. With this tool you can display the values ​​of the messages as a graph. This tool can be used, for example, to visualize sensor values. Turtlesim simulator publishes the x and y coordinates of a robot in ///turtle1/pose/x// and ///turtle1/pose/y//. Let's try to display these topics on the graph.+The //rqt_plot// tool is used to visualize the subject data over time. With this toolyou can display the values ​​of the messages as a graph. This tool can be used, for example, to visualize sensor values. Turtles simulator publishes the x and y coordinates of a robot in ///turtle1/pose/x// and ///turtle1/pose/y//. Let's try to display these topics on the graph.
  
 Run //rqt_plot//: Run //rqt_plot//:
en/ros/turtlesim.1617014748.txt.gz · Last modified: 2021/03/29 09:00 (external edit)
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