Hugo Sardinha's profile - activity

If anyone is interested, please refer to this post http://forum.erlerobotics.com/t/multi-uav-platform/3414

Hi everyone, I am trying the ROS navigation stack for the first time, and I am trying to navigate my mobile robot to a given position. Right now was trying to this using an empty map and a robot that does not have any sensors. is that possible? I've been able to move it by publishing to the cmd_vel topic, so I know that everything from the urdf to the launch files I'm using are currently okay. I was wondering I could I quickly generate an empty map, since it seems to me that's exactly what I'm missing. Any thoughts?

Thanks, Hugo

so how do you control yaw using mavros? say imagine you want to rotate 180 degrees around z

Hi Vinh, Have you managed to solve this. I have the same problem. cheers

HI RafaelGB, I am actually trying to accomplish something similar with the erlecopters. Have you been able to solve this

Hi There! Have you been able to solve this issue? When I try to launch 2 erlecopters, (I launch different instances of

How to simulate multiple erlecopters in Gazebo? Hi everyone. Is there any particular way to, correctly, launch multiple

Hi @MAS have you been able to solve this issue? thanks, Hugo

Hi @MAS have you been able to solve this issue? thanks, Hugo

HI JB, You can add the following line to your CMakeLists file in you catkin workspace set(CMAKE_CXX_FLAGS "-std=c++11

Hi JB, were you able to solve this issue?

Thank you very much mig. the stackoverflow discussion was where I found the answer to my problem. The reason why I had srand commented was because when it wasn't it still didn't work. I had to both have it outside the while loop and initialize it like suggested in the discussion.

Thank you!

Thank you very much for your comment but everything seems to be fine, from the rostopic list i get both /robot1/cmd_vel and /robot2/cmd_vel. and from rostopic info i get both publishers /robot1/pubvel and /robot2/pubvel. Naturally, rqt_graph also shows this. I still get the same cmd_vel for each...

Hello everyone,

I'm trying to have two (or several) robots receiving a random cmd_vel message. I was expecting that each robot would present a different velocity (I'm using Gazebo) but instead what I get is that every robot has the same velocity (however random, it is still the same for each one)

publisher pubvel is below as well as my launch file where I launch both the robot model and the publisher within the same namespace. One namespace for each robot.

    #include "ros/ros.h"
    #include "std_msgs/String.h"
    #include <geometry_msgs/Twist.h>
    #include <stdlib.h>


    int main(int argc, char **argv)
    {
    // Initialize the ROS system and become a node .

      ros::init(argc, argv, "publish_velocity");

      ros::NodeHandle nh;

    // Create a publisher object .
      ros::Publisher publisher = nh.advertise<geometry_msgs::Twist>("cmd_vel", 1000);

    // Loop at 2Hz until the node i s shut down.
      ros::Rate rate(2); 

    while (ros::ok())
      {
       //srand(time(0));

            geometry_msgs::Twist msg;

            msg.linear.x=double(rand())/double(RAND_MAX);
            msg.angular.z=double(rand())/double(RAND_MAX)-1;
            publisher.publish(msg);

            ROS_INFO_STREAM("Sending random velocity command:"<<" linear="<<msg.linear.x<<" angular=" <<msg.angular.z);

            rate.sleep();
      }  
      return 0;
}

<launch>

<group ns="robot1">

<param name="tf_prefix" value="robot1_tf" />

<include file="$(find random_vel)/launch_files/one_robot.launch" >

    <arg name="init_pose" value="-x 0 -y 2 -z 0" />

    <arg name="robot_name"  value="Robot1" />

    <arg name="namespace_arg" value="robot1"/>

</include>

<node pkg="random_vel" type="pubvel" name="pubvel" output="screen" />

</group>

<group ns="robot2">

<param name="tf_prefix" value="robot2_tf" />

<include file="$(find random_vel)/launch_files/one_robot.launch" >

<arg name="init_pose" value="-x 0 -y -2 -z 0" />

<arg name="robot_name"  value="Robot2" />

<arg name="namespace_arg" value="robot2"/>

</include>

<node pkg="random_vel" type="pubvel" name="pubvel" output="screen"/>

</group>

</launch>

Thank you very much in advance,

Hugo

Hello Everyone,

Does anyone know of a way to get the namespaces at runtime programmatically using roscpp? And for example, store them in an array of strings?

Cheers, Hugo