gavindvs's profile - activity

Hi all,

I am following the tutorial from this link here: http://wiki.ros.org/navigation/Tutori... Noticed that it is using tf, however I would like to code it in tf2 seeing I have gone through the tf2 tutorials.

For the broadcaster file I had converted the original tf version which is this:

#include <ros/ros.h>
#include <tf/transform_broadcaster.h>

int main(int argc, char** argv){
  ros::init(argc, argv, "robot_tf_publisher");
  ros::NodeHandle n;

  ros::Rate r(100);

  tf::TransformBroadcaster broadcaster;

  while(n.ok()){
    broadcaster.sendTransform(
      tf::StampedTransform(
        tf::Transform(tf::Quaternion(0, 0, 0, 1), tf::Vector3(0.1, 0.0, 0.2)),
        ros::Time::now(),"base_link", "base_laser"));
    r.sleep();
  }
}

To the tf2 version which I did up here (not sure if I did it correctly):

#include <ros/ros.h>
#include <tf2/LinearMath/Quaternion.h>
#include <tf2_ros/transform_broadcaster.h>
#include <geometry_msgs/TransformStamped.h>

int main(int argc, char** argv){
  ros::init(argc, argv, "robot_tf2_ros_publisher");
  ros::NodeHandle n;

  ros::Rate r(100);

  tf2_ros::TransformBroadcaster broadcaster;
  geometry_msgs::TransformStamped transformStamped;

  while(n.ok()){
    transformStamped.header.stamp = ros::Time::now();
    transformStamped.header.frame_id = "base_link";
    transformStamped.child_frame_id = "base_laser";
    transformStamped.transform.translation.x = 0.1;
    transformStamped.transform.translation.y = 0.0;
    transformStamped.transform.translation.z = 0.2;
    transformStamped.transform.rotation.x = 0;
    transformStamped.transform.rotation.y = 0;
    transformStamped.transform.rotation.z = 0;
    transformStamped.transform.rotation.w = 1;
    broadcaster.sendTransform(transformStamped);
    r.sleep();
  }
}

As for the listener file, I'm not sure how to convert it into the tf2 version :(

The original tf version of the listener file is as follows:

#include <ros/ros.h>
#include <geometry_msgs/PointStamped.h>
#include <tf/transform_listener.h>

void transformPoint(const tf::TransformListener& listener){
  //we'll create a point in the base_laser frame that we'd like to transform to the base_link frame
  geometry_msgs::PointStamped laser_point;
  laser_point.header.frame_id = "base_laser";

  //we'll just use the most recent transform available for our simple example
  laser_point.header.stamp = ros::Time();

  //just an arbitrary point in space
  laser_point.point.x = 1.0;
  laser_point.point.y = 0.2;
  laser_point.point.z = 0.0;

  try{
    geometry_msgs::PointStamped base_point;
    listener.transformPoint("base_link", laser_point, base_point);

    ROS_INFO("base_laser: (%.2f, %.2f. %.2f) -----> base_link: (%.2f, %.2f, %.2f) at time %.2f",
        laser_point.point.x, laser_point.point.y, laser_point.point.z,
        base_point.point.x, base_point.point.y, base_point.point.z, base_point.header.stamp.toSec());
  }
  catch(tf::TransformException& ex){
    ROS_ERROR("Received an exception trying to transform a point from \"base_laser\" to \"base_link\": %s", ex.what());
  }
}

int main(int argc, char** argv){
  ros::init(argc, argv, "robot_tf_listener");
  ros::NodeHandle n;

  tf::TransformListener listener(ros::Duration(10));

  //we'll transform a point once every second
  ros::Timer timer = n.createTimer(ros::Duration(1.0), boost::bind(&transformPoint, boost::ref(listener)));

  ros::spin();

}

If anyone would be able to help it would be very much appreciated.

Edit: Followed ur suggestions and changed the code. However I am getting errors :(

Listed the errors below -

/home/gavin/catkin_ws/src/robot_setup_tf/src/tf_listener.cpp: In function ‘void transformPoint(const tf2_ros::TransformListener&)’:
/home/gavin/catkin_ws/src/robot_setup_tf/src/tf_listener ...