ROS2的RCLPY库中的速率和睡眠函数

Question

最近我开始学习ROS2，但我遇到了一个问题，我创建了一个包&；定义了一个节点

#! /usr/bin/env python
import rospy
rospy.init_node("simple_node")
rate = rospy.Rate(2) # We create a Rate object of 2Hz
while not rospy.is_shutdown(): # Endless loop until Ctrl + C
    print("Help me body, you are my only hope")
    rate.sleep()
# We sleep the needed time to maintain the Rate fixed above
# This program creates an endless loop that repeats itself 2 times per second (2Hz) 
# until somebody presses Ctrl + C in the Shell

因此，我需要将上面的ROS1代码转换为ROS2，为此，我用RCLPY替换了ROSPY库，并将其编码如下：

import rclpy
def main(args=None):
    rclpy.init()
    myfirstnode = rclpy.create_node('simple_node')
    print("Help me body, you are my only hope")

if __name__ == '__main__':
    main()

现在，我想使用RCLPY实现下面给定的代码段，但我无法获得所需的所有函数，我得到了rospy.Rate(2)的RCLPY替换，它是rclpy.create_node('simple_node').create_rate(2)

while not rospy.is_shutdown():
    print("Help me body, you are my only hope")
    rate.sleep()

请推荐rospy.is_shutdown()和rospy.Rate(2).sleep()函数的RCLPY替代品

Answer 1

可以从节点创建速率对象：

self._loop_rate = self.create_rate(loop_rate, self.get_clock())

见： https://github.com/ros2/rclpy/blob/master/rclpy/rclpy/node.py

然后在循环中，您可以调用：

self._loop_rate.sleep()

见： https://github.com/ros2/rclpy/blob/master/rclpy/rclpy/timer.py