使用gazebo模拟hokuyo时报错TF_OLD_DATA

wiki上给的解决办法：

Error: TF_OLD_DATA

Example:

•  TF_OLD_DATA ignoring data from the past for frame left_gripper at time 1415804777

Solution:

• TF_OLD_DATA errors mean that a transform is attempted to be added to the system, but the data is greater than cache_time_ before the most recent data received for this link.
• The most common cause of TF_OLD_DATA warnings are if rostime has gone backwards. This can be caused by restarting a bag playback or restarting a simulator. The fix for this is to send an Empty message the topic /reset_time. There is a button in rviz to do this.

• Another possible source of TF_OLD_DATA is if there is any outdated or delayed source of transforms. The error message will tell you which authority is sending the outdated data. If it is running in a ros node you can use view_frames to determine the more recent authority. See view_frames.

　　猜想：

　　　　1.有可能是一条不同的tf_frame造成的！

　　　　2.ros时间不同步造成的可以点击rviz中的 /reset_time按钮。