Python为ROS编写一个简单的发布者和订阅者

1.创建工作空间

1.1建立文件夹hello_rospy,再在该目录下建立子目录src,并创建工作空间

mkdir -p ~/hello_rospy/src

cd ~/hello_rospy/src

catkin_init_workspace

1.2 编译

cd ~/hello_rospy/

catkin_make

1.3设置运行环境

echo “source ~/hello_rospy/devel/setup.bash” >> ~/.bashrc

1.4 检查运行环境(可以省略)

echo #ROS_PACKAGE_PATH

如果成功的话，输出内容应该包含，本空间的” …/devel/setup.bash”文件。

2.创建beginner_tutorials包

在src目录下创建beginner_tutorials包

cd ~/hello_rospy/src

catkin_create_pkg beginner_tutorials std_msgs rospy roscpp

3.编写发布者程序和订阅者程序

在beginner_tutorials 文件夹下面创建scripts文件夹，并在scripts文件夹下新建talker.py和listener.py两个文件

roscd beginner_tutorials/

mkdir scripts

cd scripts

在scripts目录下新建talker.py文件，写入如下内容：

#!/usr/bin/env python

# license removed for brevity

import rospy

from std_msgs.msg import String

def talker():

pub = rospy.Publisher(‘chatter’, String, queue_size=10)

rospy.init_node(‘talker’, anonymous=True)

rate = rospy.Rate(10) # 10hz

while not rospy.is_shutdown():

hello_str = “hello world %s” % rospy.get_time()

rospy.loginfo(hello_str)

pub.publish(hello_str)

rate.sleep()

if __name__ == ‘__main__’:

try:

talker()

except rospy.ROSInterruptException:

pass

在scripts目录下新建listener.py文件，写入如下内容：

#!/usr/bin/env python

import rospy

from std_msgs.msg import String

def callback(data):

rospy.loginfo(rospy.get_caller_id() + “I heard %s”, data.data)

def listener():

# In ROS, nodes are uniquely named. If two nodes with the same

# node are launched, the previous one is kicked off. The

# anonymous=True flag means that rospy will choose a unique

# name for our ‘listener’ node so that multiple listeners can

# run simultaneously.

rospy.init_node(‘listener’, anonymous=True)

rospy.Subscriber(“chatter”, String, callback)

# spin() simply keeps python from exiting until this node is stopped

rospy.spin()

if __name__ == ‘__main__’:

listener()

更改文件权限为可执行文件

chmod +x talker.py

chmod +x listener.py

4. 编译

(Python编写可以省略)修改Cmakelist.txt为如下：

如果是按照上面编写的，Cmakelist.txt中的内容步需要修改

cmake_minimum_required(VERSION 2.8.3)

project(beginner_tutorials)

## Find catkin macros and libraries

## if COMPONENTS list like find_package(catkin REQUIRED COMPONENTS xyz)

## is used, also find other catkin packages

find_package(catkin REQUIRED COMPONENTS

roscpp

rospy

std_msgs

)

catkin_package()

回到工作空间运行,catkin_make,编译：

catkin_make

5. 运行

cd #回到梗目录

roscore #启动ROS

rosrun beginner_tutorials talker.py

rosrun beginner_tutorials listener.py

运行结果：