ROS2(Python)Timer回调只在调用spin

2023-04-02 23:25| 来源: 网络整理| 查看: 265

我有一个ros 2回调，我想每秒调用一次，它会进行几次服务调用来检查系统另一部分的状态。不幸的是，当我包括异步服务调用（用一个小块来等待结果）时，计时器回调仍然完成，但不会再次运行。代码如下，我使用的是ROS 2版本'Humble'任何帮助都将不胜感激

import time import rclpy from rclpy.node import Node from rclpy.executors import MultiThreadedExecutor from rclpy.callback_groups import MutuallyExclusiveCallbackGroup, ReentrantCallbackGroup from container_interfaces.srv import ReadPLCBool, ReadPLCInt, WritePLCBool, WritePLCInt from plc_module.utils import error_codes, plc_variables class MonitorNode(Node): PLC_POLL_FREQUENCY = 1.0 # How often to poll the PLC to check if a tray has moved into place (in seconds) PLC_SERVICES_TIMEOUT = 10 # How long to wait for the plc services to respond to a request (in seconds) - these are pretty simple services so we shouldn't wait this long unless something has gone wrong def __init__(self) -> None: # Call the constructor for the Node class super().__init__('monitor') # Create various callback groups to ensure that the various services are called in a mutually exclusive manner self.plc_reader_callbackgroup = MutuallyExclusiveCallbackGroup() # Create various clients to interface with the PLC services - if any of these fail to connect the node will not be able to function, # so we kill the node immediately if this happens - better than allowing it to run until it tries to access a broken service and crashes self._logger.debug("Creating read bool service client") self.read_bool_client = self.create_client(ReadPLCBool, 'read_plc_bool', callback_group=self.plc_reader_callbackgroup) try: self.read_bool_client.wait_for_service(timeout_sec=10) self._logger.info("Read bool service client created") except: self._logger.fatal("'read_plc_bool' service not ready within 10s timeout - is it running?") self.destroy_node() exit() # Create a timer to periodically check the state of the PLC and trigger the other modules if necessary self.plc_monitor_timer = self.create_timer(self.PLC_POLL_FREQUENCY, self.plc_monitor_callback) def plc_monitor_callback(self) -> bool: self._logger.info("plc_monitor_callback called") request = ReadPLCBool.Request() request.data_block = 36 request.byte_index = 12 request.bit_index = 1 future = self.read_bool_client.call_async(request) self._logger.info("Made asynchronous call") while rclpy.ok(): rclpy.spin_once(self) if future.done(): self._logger.info("Asynchronous call finished") try: response = future.result() except Exception as e: self.get_logger().error("Service call failed %r" % (e,)) break else: self._logger.info("Got response: {}".format(response.value)) break self._logger.info("plc_monitor_callback finished") return def main(args=None): # Create an instance of the node and spin it rclpy.init(args=args) monitor = MonitorNode() try: rclpy.spin(monitor) except KeyboardInterrupt: pass feed_initialiser.destroy_node() rclpy.shutdown() if __name__ == '__main__': main()

当我运行这段代码时，我看到所有打印的消息，直到并包括'plc_monitor_callback finished'，但之后什么也没有。'read_plc_bool'服务在另一个节点中按预期运行，并且在我的监视器节点挂起后继续可调用-目前它在一个单独的终端窗口中运行，尽管计划是从启动文件运行这两个窗口。我尝试过设置回调组和执行器的不同配置，以及使用对此服务的同步调用，尽管这些尝试似乎没有帮助。

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