Traversing a robot in a prespecified path

edit

Hi! Last day i was trying out an experiment to traverse a robot in a pre specified path (say a mathematical curve). To keep thing simple at the beginning I choose a straight path. I made a learning_joy package and added the following code in the learning_joy/src/turtle_teleop_joy.cpp:

#include "ros/ros.h"
#include "turtlesim/Velocity.h"
#include "geometry_msgs/Twist.h"

class TeleopTurtle
{
public:
    TeleopTurtle();

    void move_robot();

    ros::NodeHandle nh_;

    ros::Publisher vel_pub_;
};


TeleopTurtle::TeleopTurtle()
{
    vel_pub_ = nh_.advertise<geometry_msgs::Twist>("base_controller/command",1);

    move_robot();
}

void TeleopTurtle::move_robot()
{
    geometry_msgs::Twist cmdvel;

    int i = 0;
    while(i < 100) //continue publishing the message
    {
        cmdvel.angular.z = 0;
        cmdvel.linear.x = 2;
        vel_pub_.publish(cmdvel);
        i++;
    }
}

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

    TeleopTurtle teleop_turtle;

    ros::spin();
}

the steps i followed after that are:

$ roscore

$ roscd stage
./bin/stageros world/willow-erratic.world
$ rosmake learning_joy

$ rosrun learning_joy turtle_teleop_joy

This does not give any errors but the robot does not move. rxgraph shows that the node is running. Can you please tell me the reason as to why this does not work ? Regards!