tf代码实例

catkin_create_pkg learning_tf tf roscpp rospy turtlesim

#include <ros/ros.h>

#include <tf/transform_broadcaster.h>

#include <turtlesim/Pose.h>

std::string turtle_name;

void poseCallback(const turtlesim::PoseConstPtr& msg)

{

     static tf::TransformBroadcaster br;

     tf::Transform transform;

     transform.setOrigin( tf::Vector3(msg->x, msg->y, 0.0) );

     tf::Quaternion q;

     q.setRPY(0, 0, msg->theta);

     transform.setRotation(q);

     br.sendTransform(tf::StampedTransform(transform, ros::Time::now(), "world", turtle_name));

}

int main(int argc, char** argv)

{

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

   if (argc != 2){ROS_ERROR("need turtle name as argument"); return -1;};

   turtle_name = argv[1];

   ros::NodeHandle node;

   ros::Subscriber sub = node.subscribe(turtle_name+"/pose", 10, &poseCallback);

   ros::spin();

   return 0;

}

------------------------------------------------------------------------------------------------------------

#include <ros/ros.h>
#include <tf/transform_listener.h>
#include <geometry_msgs/Twist.h>
#include <turtlesim/Spawn.h>

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

  ros::NodeHandle node;

  ros::service::waitForService("spawn");
  ros::ServiceClient add_turtle =
    node.serviceClient<turtlesim::Spawn>("spawn");
  turtlesim::Spawn srv;
  add_turtle.call(srv);

  ros::Publisher turtle_vel =
    node.advertise<geometry_msgs::Twist>("turtle2/cmd_vel", 10);

  tf::TransformListener listener;

  ros::Rate rate(10.0);
  while (node.ok()){
    tf::StampedTransform transform;
    try{
      listener.lookupTransform("/turtle2", "/turtle1",
                               ros::Time(0), transform);
    }
    catch (tf::TransformException &ex) {
      ROS_ERROR("%s",ex.what());
      ros::Duration(1.0).sleep();
      continue;
    }

    geometry_msgs::Twist vel_msg;
    vel_msg.angular.z = 4.0 * atan2(transform.getOrigin().y(),
                                    transform.getOrigin().x());
    vel_msg.linear.x = 0.5 * sqrt(pow(transform.getOrigin().x(), 2) +
                                  pow(transform.getOrigin().y(), 2));
    turtle_vel.publish(vel_msg);

    rate.sleep();
  }
  return 0;
};