如何去实现一个TF广播器呢

TF广播器是怎样去定义的？
如何去实现一个TF广播器呢？

回帖（1）

李富贵

2022-2-14 10:11:30

创建功能包
cd ~/catkin_workspace/src
catkin_create_pkg learning_tf roscpp rospy tf turtlesim
如何实现一个tf广播器
定义TF广播器（TransformBroadcaster）
创建坐标变换值；
发布坐标变换（sendTransform）
创建tf广播器代码（C++）
nano ~/catkin_workspace/src/learning_tf/src/turtle_tf_broadcaster.cpp
/***********************************************************************
Copyright 2020 GuYueHome (www.guyuehome.com).
***********************************************************************/
/**
* 该例程产生tf数据，并计算、发布turtle2的速度指令
*/
#include
#include
#include
std::string turtle_name;
void poseCallback(const turtlesim::PoseConstPtr& msg)
{
// 创建tf的广播器
static tf::TransformBroadcaster br;
// 初始化tf数据
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);
// 广播world与海龟坐标系之间的tf数据
br.sendTransform(tf::StampedTransform(transform, ros::Time::now(), "world", turtle_name));
}
int main(int argc, char** argv)
{
// 初始化ROS节点
ros::init(argc, argv, "my_tf_broadcaster");
// 输入参数作为海龟的名字
if (argc != 2)
{
ROS_ERROR("need turtle name as argument");
return -1;
}
turtle_name = argv[1];
// 订阅海龟的位姿话题
ros::NodeHandle node;
ros::Subscriber sub = node.subscribe(turtle_name+"/pose", 10, &poseCallback);
// 循环等待回调函数
ros::spin();
return 0;
};
配置编译规则
nano ~/catkin_workspace/src/learning_tf/CMakeLists.txt
add_executable(turtle_tf_broadcaster src/turtle_tf_broadcaster.cpp)
target_link_libraries(turtle_tf_broadcaster ${catkin_LIBRARIES})
add_executable(turtle_tf_listener src/turtle_tf_listener.cpp)
target_link_libraries(turtle_tf_listener ${catkin_LIBRARIES})

编译并运行
cd ~/catkin_workspace
catkin_make
# 新建一个终端
source ~/catkin_workspace/devel/setup.bash
roscore
# 新建一个终端
source ~/catkin_workspace/devel/setup.bash
rosrun turtlesim turtlesim_node
# 新建一个终端
source ~/catkin_workspace/devel/setup.bash
rosrun learning_tf turtle_tf_broadcaster __name:=turtle1_tf_broadcaster /turtle1
# 新建一个终端
source ~/catkin_workspace/devel/setup.bash
rosrun learning_tf turtle_tf_broadcaster __name:=turtle2_tf_broadcaster /turtle2
# 新建一个终端
source ~/catkin_workspace/devel/setup.bash
rosrun learning_tf turtle_tf_listener
# 新建一个终端
source ~/catkin_workspace/devel/setup.bash
rosrun turtlesim turtle_teleop_key
# 新建一个终端
source ~/catkin_workspace/devel/setup.bash
rqt_graph

python
编写程序
cd ~/catkin_workspace/src/learning_tf
mkdir scripts
1
2
turtle_tf_broadcaster.py
nano ~/catkin_workspace/src/learning_tf/scripts/turtle_tf_broadcaster.py
1
#!/usr/bin/env python
# -*- coding: utf-8 -*-
########################################################################
####       Copyright 2020 GuYueHome (www.guyuehome.com).       ###
########################################################################
# 该例程将请求/show_person服务，服务数据类型learning_service::Person
import roslib
roslib.load_manifest('learning_tf')
import rospy
import tf
import turtlesim.msg
def handle_turtle_pose(msg, turtlename):
br = tf.TransformBroadcaster()
br.sendTransform((msg.x, msg.y, 0),
                  tf.transformations.quaternion_from_euler(0, 0, msg.theta),
                  rospy.Time.now(),
                  turtlename,
                  "world")
if __name__ == '__main__':
rospy.init_node('turtle_tf_broadcaster')
turtlename = rospy.get_param('~turtle')
rospy.Subscriber('/%s/pose' % turtlename,
                  turtlesim.msg.Pose,
                  handle_turtle_pose,
                  turtlename)
rospy.spin()
turtle_tf_listener.py
nano ~/catkin_workspace/src/learning_tf/scripts/turtle_tf_listener.py
#!/usr/bin/env python
# -*- coding: utf-8 -*-
########################################################################
####       Copyright 2020 GuYueHome (www.guyuehome.com).       ###
########################################################################
# 该例程将请求/show_person服务，服务数据类型learning_service::Person
import roslib
roslib.load_manifest('learning_tf')
import rospy
import math
import tf
import geometry_msgs.msg
import turtlesim.srv
if __name__ == '__main__':
rospy.init_node('turtle_tf_listener')
listener = tf.TransformListener()
rospy.wait_for_service('spawn')
spawner = rospy.ServiceProxy('spawn', turtlesim.srv.Spawn)
spawner(4, 2, 0, 'turtle2')
turtle_vel = rospy.Publisher('turtle2/cmd_vel', geometry_msgs.msg.Twist,queue_size=1)
rate = rospy.Rate(10.0)
while not rospy.is_shutdown():
      try:
         (trans,rot) = listener.lookupTransform('/turtle2', '/turtle1', rospy.Time(0))
      except (tf.LookupException, tf.ConnectivityException, tf.ExtrapolationException):
         continue
      angular = 4 * math.atan2(trans[1], trans[0])
      linear = 0.5 * math.sqrt(trans[0] ** 2 + trans[1] ** 2)
      cmd = geometry_msgs.msg.Twist()
      cmd.linear.x = linear
      cmd.angular.z = angular
      turtle_vel.publish(cmd)
      rate.sleep()
运行
sudo chmod +x ~/catkin_workspace/src/learning_tf/scripts/turtle_tf_broadcaster.py
sudo chmod +x ~/catkin_workspace/src/learning_tf/scripts/turtle_tf_listener.py
# 新建一个终端
source ~/catkin_workspace/devel/setup.bash
roscore
# 新建一个终端
source ~/catkin_workspace/devel/setup.bash
rosrun turtlesim turtlesim_node
# 新建一个终端
source ~/catkin_workspace/devel/setup.bash
rosrun learning_tf turtle_tf_broadcaster.py __name:=turtle1_tf_broadcaster _turtle:=turtle1
# 新建一个终端
source ~/catkin_workspace/devel/setup.bash
rosrun learning_tf turtle_tf_broadcaster.py __name:=turtle2_tf_broadcaster _turtle:=turtle2
# 新建一个终端
source ~/catkin_workspace/devel/setup.bash
rosrun learning_tf turtle_tf_listener.py
# 新建一个终端
source ~/catkin_workspace/devel/setup.bash
rosrun turtlesim turtle_teleop_key
# 新建一个终端
source ~/catkin_workspace/devel/setup.bash
rqt_graph