[Python知识库]以ros为媒介进行数据采集

以ros为媒介进行数据采集

最近在学习usvsim,是在ros环境下进行的，所以就正好学习ros

目的是将无人船行进数据采集到，所以要在他的环境包里再建一个subscriber

关于数据查看
利用topic
rostopic list查看topic功能菜单
链接: ROS学习笔记五：理解ROS topics.
可以看到/gazebo/model_states这个就是船的位置信息
只要能显示出来就是能传出来。

建subscriber
链接: ROS中编写Publisher和Subscriber的方法（Python版）.

链接: ROS Publisher c++ 与 Python 实现.

链接: ROS编译 Python 文件(详细说明).

下面是我自己整合及遇到的问题，我是py

cd ~/catkin_ws/src
catkin_create_pkg beginner_tutorials std_msgs rospy roscpp
roscd beginner_tutorials
mkdir scripts
cd scripts

然后编译一下

catkin_make -DCATKIN_WHITELIST_PACKAGES="my_pkg"

UGVinformation_xy.py

#!/usr/bin/env python

from gazebo_msgs.msg import ModelStates
import rospy
import numpy as np
from new_thread_test import Job


def callback(msg):
    global current_state
    current_state = rospy.Time.to_time(rospy.Time.now())
    current_state = np.append(current_state, msg)

if __name__ == "__main__":
    rospy.init_node("UAVInformation")
    UAV_state = rospy.Subscriber("/gazebo/model_states", ModelStates, callback)
    current_state = []
    add_thread = Job()
    add_thread.start()
    add_thread.pause()
    list_all = []
    while True:
        add_thread.resume()
        last_time = rospy.Time.now()
        while True:
            if rospy.Time.now() - last_time > rospy.Duration(5).__div__(10):
                list_all.append(current_state)
                print current_state
                break
        if len(list_all) > 100:
            break
    with open("information.txt", "w") as f:
        for _ in list_all:
            f.write(str(_))
            f.write("\r")

在里面新建一个文档，复制粘贴进

UAVinformation_xyz.py

#!/usr/bin/env python

from gazebo_msgs.msg import ModelStates
import rospy
import numpy as np
from new_thread_test import Job

def callback(msg):
    global current_state
    current_state = rospy.Time.to_time(rospy.Time.now())
    current_state = np.append(current_state, msg)


if __name__ == "__main__":
    rospy.init_node("UAVInformation")
    UAV_state = rospy.Subscriber("/gazebo/model_states", ModelStates, callback)
    current_state = []
    add_thread = Job()
    add_thread.start()
    add_thread.pause()
    while True:
        add_thread.resume()
        last_time = rospy.Time.now()
        while True:
            if rospy.Time.now() - last_time > rospy.Duration(4):
                print current_state
                break

new_thread_test.py

#!/usr/bin/env python
# coding: utf-8

import threading
import time
import rospy

class Job(threading.Thread):

    def __init__(self, *args, **kwargs):
        super(Job, self).__init__(*args, **kwargs)
        self.__flag = threading.Event()  # 用于暂停线程的标识
        self.__flag.set()  # 设置为True
        self.__running = threading.Event()  # 用于停止线程的标识
        self.__running.set()  # 将running设置为True


    def run(self):
        while self.__running.isSet():
            self.__flag.wait()  # 为True时立即返回, 为False时阻塞直到内部的标识位为True后返
            rospy.spin()

    def pause(self):
        self.__flag.clear()  # 设置为False, 让线程阻塞

    def resume(self):
        self.__flag.set()  # 设置为True, 让线程停止阻塞

    def stop(self):
        self.__flag.set()  # 将线程从暂停状态恢复, 如何已经暂停的话
        self.__running.clear()  # 设置为False


# a = Job()
# a.start()
# print 'start'
# time.sleep(3)
# a.pause()
# print 'pause'
# time.sleep(3)
# a.resume()
# print 'resume'
# time.sleep(3)
# a.pause()
# print 'pause'
# time.sleep(2)
# a.stop()
# print 'stop'

cd ~/catkin_ws/src
source ~/catkin_ws/devel/setup.bash
rosrun beginner_tutorials UAVinformation_xyz.py

运行一下，记得更改权限为可执行文件。