URDF文件转Xacro文件、在rviz和gazebo中同时启动

URDF文件、Xacro文件介绍及参考教程

URDF、Xacro编写及介绍及其在RVIZ中显示与控制:
https://blog.youkuaiyun.com/answerMack/article/details/89523746
urdf教程：http://wiki.ros.org/urdf/Tutorials
solidworks转urdf教程：
1.http://wiki.ros.org/sw_urdf_exporter
2.https://blog.youkuaiyun.com/gpeng832/article/details/73917487
moveit setup assistant教程：
1.http://docs.ros.org/indigo/api/moveit_tutorials/html/doc/setup_assistant/setup_assistant_tutorial.html
2.http://docs.ros.org/hydro/api/moveit_setup_assistant/html/doc/tutorial.html
urdf转xacro参考教程：
1.http://wiki.ros.org/urdf/Tutorials/Using Xacro to Clean Up a URDF File

文件目录：

urdf文件

<robot
  name="car-3">
  <link
    name="base_link">
    <inertial>
      <origin
        xyz="0.000454836605433948 1.27332861349781E-18 0.000181934642173575"
        rpy="0 0 0" />
      <mass
        value="0.497309733552923" />
      <inertia
        ixx="0.000379491084127215"
        ixy="-2.59493525107028E-19"
        ixz="-3.57796209039485E-06"
        iyy="0.00138864533975945"
        iyz="-4.48378120593819E-21"
        izz="0.00169173411179082" />
    </inertial>
    <visual>
      <origin
        xyz="0 0 0"
        rpy="0 0 0" />
      <geometry>
        <mesh
          filename="package://car-3/meshes/base_link.STL" />
      </geometry>
      <material
        name="">
        <color
          rgba="1 1 1 1" />
      </material>
    </visual>
    <collision>
      <origin
        xyz="0 0 0"
        rpy="0 0 0" />
      <geometry>
        <mesh
          filename="package://car-3/meshes/base_link.STL" />
      </geometry>
    </collision>
  </link>
  <link
    name="wheel_1">
    <inertial>
      <origin
        xyz="2.08756043780373E-05 5.32859680283521E-06 -6.93889390390723E-18"
        rpy="0 0 0" />
      <mass
        value="0.0282994666235368" />
      <inertia
        ixx="6.59828205801096E-06"
        ixy="-3.54146284907832E-09"
        ixz="-4.2351647362715E-22"
        iyy="1.27373747424717E-05"
        iyz="7.11375326795604E-23"
        izz="6.61215628796161E-06" />
    </inertial>
    <visual>
      <origin
        xyz="0 0 0"
        rpy="0 0 0" />
      <geometry>
        <mesh
          filename="package://car-3/meshes/wheel_1.STL" />
      </geometry>
      <material
        name="">
        <color
          rgba="1 1 1 1" />
      </material>
    </visual>
    <collision>
      <origin
        xyz="0 0 0"
        rpy="0 0 0" />
      <geometry>
        <mesh
          filename="package://car-3/meshes/wheel_1.STL" />
      </geometry>
    </collision>
  </link>
  <joint
    name="wheel_1_to_base_link"
    type="continuous">
    <origin
      xyz="0.07 0.052 0"
      rpy="0 -0.75239 0" />
    <parent
      link="base_link" />
    <child
      link="wheel_1" />
    <axis
      xyz="0 1 0" />
  </joint>
  <link
    name="wheel_2">
    <inertial>
      <origin
        xyz="2.08756043780373E-05 5.32859680283521E-06 -1.44387083394547E-35"
        rpy="0 0 0" />
      <mass
        value="0.0282994666235368" />
      <inertia
        ixx="6.59828205801097E-06"
        ixy="-3.54146284907845E-09"
        ixz="4.94314925543529E-39"
        iyy="1.27373747424718E-05"
        iyz="-8.12167230901508E-39"
        izz="6.61215628796161E-06" />
    </inertial>
    <visual>
      <origin
        xyz="0 0 0"
        rpy="0 0 0" />
      <geometry>
        <mesh
          filename="package://car-3/meshes/wheel_2.STL" />
      </geometry>
      <material
        name="">