Using ROS namespaces programmaticaly

Question

It seems like the simple question, but is it possible to control robots with different ROS namespaces in one launch file programmaticaly? For example, i want to move robot1 one meter forward, and robot2 one meter backward programmaticaly in one file. Also i wonder if it is possible for a launch file which is launched for example in ROS_NAMESPACE=robot1, to programmaticaly control nodes of another robot in ROS_NAMESPACE=robot2? Thanks for answers.

Edit:

For example, i use code from this tutorial

What i want to know is, if it is somehow possible to write code like this:

#include <ros/ros.h>
#include <move_base_msgs/MoveBaseAction.h>
#include <actionlib/client/simple_action_client.h>

typedef actionlib::SimpleActionClient<move_base_msgs::MoveBaseAction> MoveBaseClient;

int main(int argc, char** argv){
  ros::init(argc, argv, "simple_navigation_goals");

  //tell the action client that we want to spin a thread by default
  MoveBaseClient ac("tb3_0/move_base", true);

  //wait for the action server to come up 
  while(!ac.waitForServer(ros::Duration(5.0))){
    ROS_INFO("Waiting for the move_base action server to come up");
 }

 move_base_msgs::MoveBaseGoal goal;

 //we'll send a goal to the robot to move 1 meter forward
 goal.target_pose.header.frame_id = "tb3_0/base_link";
 goal.target_pose.header.stamp = ros::Time::now();

 goal.target_pose.pose.position.x = 1.0;
 goal.target_pose.pose.orientation.w = 1.0;

 ROS_INFO("Sending goal");
 ac.sendGoal(goal);

 ac.waitForResult();

 if(ac.getState() == actionlib::SimpleClientGoalState::SUCCEEDED)
    ROS_INFO("Hooray, the base moved 1 meter forward");
 else
    ROS_INFO("The base failed to move forward 1 meter for some reason");

return 0;
}

My goal would be to add two more move_base clients to control more robots from different namespace in this one source file.

---Edit---

I found out, this example is possible.

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Originally posted by MarosROS on ROS Answers with karma: 33 on 2020-03-03

Post score: 0

Answer 1

Hello,

Yes it is possible to control multiple robots using ROS namespaces. Every robot will have its own attributes (topics, services etc.) appended with its very own name.

I didn't understood in one launch file programmaticaly? but I will answer it with two possibilities.

1. You can launch robot software using roslaunch api, you can find a few example here on how to use this api.

2. You can use launch file and use namespaces and other arguments to control each of your robot.

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Originally posted by Tahir M. with karma: 213 on 2020-03-04

This answer was ACCEPTED on the original site

Post score: 2

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Original comments

Comment by MarosROS on 2020-03-04:
@Tahir Mehmood I edited the question with the example

Answer 2

Try in your launch file

<group ns="robot1">
<robot launch files etc>
<remap from="cmd" to="/robot2/cmd"/>
</group>

<group ns="robot2">
<robot launch files etc>
</group>

This will put your robots in separate namespaces with ns, and the remap will make the topic cmd be changed to /robot2/cmd the leading slash in front tells ros to ignore your namespace declaration for this remapped topic. Hope that at least gives you a hint!

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Originally posted by LukeBowersox with karma: 31 on 2020-04-01

This answer was NOT ACCEPTED on the original site

Post score: 1

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Original comments

Comment by MarosROS on 2020-04-02:
Thanks this was also very helpful.