[gazebo仿真]给模型添加多线激光雷达

以sumit_xl模型为例，若sumit_xl模型git下载不下来，可通过https://download.youkuaiyun.com/download/Travis_X/12321738下载。

$ cd ~/catkin_ws/src 
$ git clone https://TheConstruct@bitbucket.org/theconstructcore/summit_xl.git -b kinetic
$ cd ..
$ catkin_make

下载Velodyne_description工具包或者直接sudo apt-get install ros-kinetic-velodyne-*

修改summit_xl_omni.urdf.xacro文件,添加多线雷达模型

16线激光雷达或32线激光雷达

  <!-- VLP-16 -->
  <xacro:include filename="$(find velodyne_description)/urdf/VLP-16.urdf.xacro"/>
  <VLP-16 parent="base_link" name="velodyne" topic="/velodyne_points" hz="10" samples="1024" gpu="false" lasers="16" max_range="100">
    <origin xyz="0 0 0.5" rpy="0 0 0" />
  </VLP-16>

    <!-- VHDL-32E -->
	<xacro:include filename="$(find velodyne_description)/urdf/HDL-32E.urdf.xacro"/>
  	<HDL-32E pa