如何在ROS2 Foxy中通过Python节点停止或终止Nav2导航？

方法1：通过Action客户端取消当前导航目标 #

Nav2的核心导航功能（如NavigateToPose、FollowWaypoints）基于ROS2 Action实现，可通过对应Action客户端发送取消请求终止导航。

以下是针对NavigateToPose Action的Python实现示例：

import rclpy
from rclpy.action import ActionClient
from rclpy.node import Node
from nav2_msgs.action import NavigateToPose

class Nav2Stopper(Node):
    def __init__(self):
        super().__init__('nav2_stopper_node')
        self._action_client = ActionClient(self, NavigateToPose, 'navigate_to_pose')
        self.current_goal_handle = None

    def send_cancel_request(self):
        if self.current_goal_handle is not None:
            future = self.current_goal_handle.cancel_goal_async()
            rclpy.spin_until_future_complete(self, future)
            if future.result() is not None:
                self.get_logger().info('导航已成功取消')
            else:
                self.get_logger().error('取消导航请求失败')
        else:
            self.get_logger().warn('当前没有正在执行的导航目标')

    # 若需启动导航并记录目标句柄，可添加此方法
    def send_nav_goal(self, pose):
        goal_msg = NavigateToPose.Goal()
        goal_msg.pose = pose
        self._action_client.wait_for_server()
        send_goal_future = self._action_client.send_goal_async(goal_msg)
        rclpy.spin_until_future_complete(self, send_goal_future)
        self.current_goal_handle = send_goal_future.result()
        if not self.current_goal_handle.accepted:
            self.get_logger().error('导航目标被拒绝')
            return
        self.get_logger().info('导航目标已接受')

def main(args=None):
    rclpy.init(args=args)
    stopper = Nav2Stopper()
    stopper.send_cancel_request()
    stopper.destroy_node()
    rclpy.shutdown()

if __name__ == '__main__':
    main()

若使用FollowWaypoints Action，只需将Action类型改为nav2_msgs.action.FollowWaypoints，并将Action话题替换为follow_waypoints即可。

方法2：调用Nav2的cancel_all_goals服务 #

Nav2提供cancel_all_goals服务（类型为std_srvs/srv/Empty），调用该服务可直接取消所有正在执行的导航任务。

Python实现示例：

import rclpy
from rclpy.node import Node
from std_srvs.srv import Empty

class Nav2CancelService(Node):
    def __init__(self):
        super().__init__('nav2_cancel_service_client')
        self.cli = self.create_client(Empty, 'cancel_all_goals')
        while not self.cli.wait_for_service(timeout_sec=1.0):
            self.get_logger().info('服务未启动，等待中...')
        self.req = Empty.Request()

    def send_request(self):
        future = self.cli.call_async(self.req)
        rclpy.spin_until_future_complete(self, future)
        if future.result() is not None:
            self.get_logger().info('所有导航目标已取消')
        else:
            self.get_logger().error('调用取消服务失败')

def main(args=None):
    rclpy.init(args=args)
    cancel_client = Nav2CancelService()
    cancel_client.send_request()
    cancel_client.destroy_node()
    rclpy.shutdown()

if __name__ == '__main__':
    main()

注意事项 #

• 确保Python节点运行时与Nav2节点处于同一ROS2域，且具备足够权限。
• 使用Action取消方式时，需确保正确记录了goal_handle，否则无法发起有效取消请求。
• 若Nav2配置中自定义了Action或服务话题名称，需将示例中的话题名替换为实际使用的名称。

内容的提问来源于stack exchange，提问作者Sachmk2