問題

状況

Python経由でROSを使用
TFをlistenしようとしていた

コード

cmd_vel_pub = rospy.Publisher("/hoge/command_velocity", Twist, queue_size = 1)
tflistener= tf.TransformListener()
twist = Twist()
rate = rospy.Rate(control_hz)

エラー

Traceback (most recent call last):
  File "test.py", line 26, in <module>
    tflistener= tf.TransformListener()
  File "/opt/ros/noetic/lib/python3/dist-packages/tf/listener.py", line 367, in __init__
    self._listener = tf2_ros.TransformListener(self._buffer)
  File "/opt/ros/noetic/lib/python3/dist-packages/tf2_ros/transform_listener.py", line 54, in __init__
    self.last_update = rospy.Time.now()
  File "/opt/ros/noetic/lib/python3/dist-packages/rospy/rostime.py", line 155, in now
    return get_rostime()
  File "/opt/ros/noetic/lib/python3/dist-packages/rospy/rostime.py", line 190, in get_rostime
    raise rospy.exceptions.ROSInitException("time is not initialized. Have you called init_node()?")
rospy.exceptions.ROSInitException: time is not initialized. Have you called init_node()?
Exception ignored in: <function TransformListener.__del__ at 0x7fd240de4670>
Traceback (most recent call last):
  File "/opt/ros/noetic/lib/python3/dist-packages/tf2_ros/transform_listener.py", line 60, in __del__
    self.unregister()
  File "/opt/ros/noetic/lib/python3/dist-packages/tf2_ros/transform_listener.py", line 66, in unregister
    self.tf_sub.unregister()
AttributeError: 'TransformListener' object has no attribute 'tf_sub'

解決方法

ちゃんとinit_nodeする

rospy.init_node('atarimae_taisou')

所感

あたりまえすぎたが最後のエラーだけ見てもミスにすぐ気づけなかったため。（よく読めばHave you called init_node()?と言われているが）