Gazebo仿真遇到的一些奇怪的问题

在调试过程中发现以下奇怪的错误，在ROS社区里也没有找到行之有效的解决方法：

• MSG to TF: Quaternion Not Properly Normalized
• Could not get robot pose, cancelling pose reconfiguration
• Gazebo ROS Kobuki plugin: NaN in d1. Step time: 0.001, WD: 0.07, velocity: nan
• Gazebo ROS Kobuki plugin: NaN in d2. Step time: 0.001, WD: 0.07, velocity: nan
• TF_DENORMALIZED_QUATERNION: Ignoring transform for child_frame_id "base_footprint" from authority "unknown_publisher" because of an invalid quaternion in the transform (nan nan nan nan)
• Error:   TF_NAN_INPUT: Ignoring transform for child_frame_id "base_footprint" from authority "unknown_publisher" because of an invalid quaternion in the transform (nan nan nan nan)
  at line 257 in /tmp/binarydeb/ros-indigo-tf2-0.5.20/src/buffer_core.cpp
• Error:   TF_NAN_INPUT: Ignoring transform for child_frame_id "base_footprint" from authority "unknown_publisher" because of a nan value in the transform (nan nan 0.000000) (nan nan nan nan)
  at line 244 in /tmp/binarydeb/ros-indigo-tf2-0.5.20/src/buffer_core.cpp

这里只提供一种解决问题的思路：

第一步：检查相关package是否启动，如velocity_mux、safety_controller、velocity_smoother等等；

第二步：检查话题名称是否配置准确，如odom_topic、odom_frame、cmd_vel_topic等等。

• 20190523更新

在利用Gazebo和RViz仿真时，会出现下面这种现象：turtlebot2撞到“墙”继续顶着“墙”前进，Gazebo上显示turtlebot2位置未变化，而RViz上显示turtlebot2位置发生了变化，似乎无解。

https://answers.ros.org/question/293480/turtlebot-odom-and-a-wall/