我们在很多时候会需要保存一些文件以记录相关信息。
所以如何保存,我们第一个项目是想要保存rviz上点击的waypoints点。
代码如下:
import yaml import rospy import geometry_msgs.msg as geometry_msgs class WaypointGenerator(object): def __init__(self, filename): self._sub_pose = rospy.Subscriber(‘clicked_point‘, geometry_msgs.PointStamped, self._process_pose, queue_size=1) self._waypoints = [] self._filename = filename def _process_pose(self, msg): p = msg.point data = {} data[‘frame_id‘] = msg.header.frame_id data[‘pose‘] = {} data[‘pose‘][‘position‘] = {‘x‘: p.x, ‘y‘: p.y, ‘z‘: 0.0} data[‘pose‘][‘orientation‘] = {‘x‘: 0, ‘y‘: 0, ‘z‘: 0, ‘w‘:1} data[‘name‘] = ‘%s_%s‘ % (p.x, p.y) self._waypoints.append(data) rospy.loginfo("Clicked : (%s, %s, %s)" % (p.x, p.y, p.z)) def _write_file(self): ways = {} ways[‘waypoints‘] = self._waypoints with open(self._filename, ‘w‘) as f: f.write(yaml.dump(ways, default_flow_style=False)) def spin(self): rospy.spin() self._write_file() if __name__ == ‘__main__‘: rospy.init_node(‘waypoint_generator‘) filename = rospy.get_param(‘~filename‘) g = WaypointGenerator(filename) rospy.loginfo(‘Initialized‘) g.spin() rospy.loginfo(‘ByeBye‘)
这个node就是订阅了rviz里面的Publish Point进行存储。
Make文件应该是这样的:
cmake_minimum_required(VERSION 2.8.3) project(waypoint_generator) find_package(catkin REQUIRED COMPONENTS geometry_msgs rospy ) catkin_python_setup() catkin_package() install(PROGRAMS scripts/generator.py DESTINATION ${CATKIN_PACKAGE_BIN_DESTINATION} )
我们在写一个launch文件,写好文件存储位置。
<launch> <node pkg="waypoint_generator" type="generator.py" name="waypoint_generator" output="screen" > <param name="filename" value="$(find waypoint_generator)/output.txt" /> </node> <node pkg="show_path" type="showpath" name="showpath"/> </launch>
存储位置就是package下面主目录里。
下面是读取txt文件并且发布为goal,其中还包括了actionlib的用法。
import random import rospy import actionlib import waypoint_touring.utils as utils import move_base_msgs.msg as move_base_msgs import visualization_msgs.msg as viz_msgs class TourMachine(object): def __init__(self, filename, random_visits=False, repeat=False): self._waypoints = utils.get_waypoints(filename) action_name = ‘move_base‘ self._ac_move_base = actionlib.SimpleActionClient(action_name, move_base_msgs.MoveBaseAction) rospy.loginfo(‘Wait for %s server‘ % action_name) self._ac_move_base.wait_for_server self._counter = 0 self._repeat = repeat self._random_visits = random_visits if self._random_visits: random.shuffle(self._waypoints) self._pub_viz_marker = rospy.Publisher(‘viz_waypoints‘, viz_msgs.MarkerArray, queue_size=1, latch=True) self._viz_markers = utils.create_viz_markers(self._waypoints) def move_to_next(self): p = self._get_next_destination() if not p: rospy.loginfo("Finishing Tour") return True goal = utils.create_move_base_goal(p) rospy.loginfo("Move to %s" % p[‘name‘]) self._ac_move_base.send_goal(goal) self._ac_move_base.wait_for_result() result = self._ac_move_base.get_result() rospy.loginfo("Result : %s" % result) return False def _get_next_destination(self): if self._counter == len(self._waypoints): if self._repeat: self._counter = 0 if self._random_visits: random.shuffle(self._waypoints) else: next_destination = None next_destination = self._waypoints[self._counter] self._counter = self._counter + 1 return next_destination def spin(self): rospy.sleep(1.0) self._pub_viz_marker.publish(self._viz_markers) finished = False while not rospy.is_shutdown() and not finished: finished = self.move_to_next() rospy.sleep(2.0) if __name__ == ‘__main__‘: rospy.init_node(‘tour‘) filename = rospy.get_param(‘~filename‘) random_visits = rospy.get_param(‘~random‘, False) repeat = rospy.get_param(‘~repeat‘, False) m = TourMachine(filename, random_visits, repeat) rospy.loginfo(‘Initialized‘) m.spin() rospy.loginfo(‘Bye Bye‘)
而写一个launch文件来读取txt位置,
<launch> <arg name="repeat" default="true"/> <arg name="random" default="false"/> <arg name="filename" default="$(find waypoint_generator)/output.txt"/> <node pkg="rviz" type="rviz" name="rviz" /> <node pkg="waypoint_touring" name="waypoint_touring" type="tour.py" output="screen"> <param name="filename" value="$(arg filename)"/> <param name="repeat" value="$(arg repeat)"/> <param name="random" value="$(arg random)"/> </node> </launch>
参考资料: