Inertia tensor of URDF file

edit

I use gazebo and simulate 6DOF manipulator(It is Ufactory Lite6). Then I need inertia tensor in urdf file.

Which axis or center should I inertia tensor calculate from? For example, around the center of gravity or around the joint axis or other axis.

Please tell me.

A part of urdf file

<link name="${prefix}link1">
  <inertial>
    <origin
      xyz="-0.00036 0.042 -0.0025"
      rpy="0 0 0" />
    <mass
      value="1.411" />
    <inertia
      ixx="1.45164E-03"
      ixy="1.24E-05"
      ixz="-6.7E-06"
      iyy="8.873E-04"
      iyz="1.255E-04"
      izz="1.31993E-03" />
  </inertial>
  <visual>
    <origin
      xyz="0 0 0"
      rpy="0 0 0" />
    <geometry>
      <mesh filename="package://xarm_description/meshes/lite6/visual/link1.stl"/>
    </geometry>
    <material name="${prefix}White" />
  </visual>
  <collision>
    <origin
      xyz="0 0 0"
      rpy="0 0 0" />
    <geometry>
      <mesh filename="package://xarm_description/meshes/lite6/collision/link1.stl"/>
    </geometry>
  </collision>
</link>
<joint name="${prefix}joint1" type="revolute">
  <origin
    xyz="0 0 0.2433"
    rpy="0 0 0" />
  <parent
    link="${prefix}link_base" />
  <child
    link="${prefix}link1" />
  <axis
    xyz="0 0 1" />
  <limit
    lower="${joint1_lower_limit}"
    upper="${joint1_upper_limit}"
    effort="32.0"
    velocity="3.14"/>
  <dynamics damping="1.0" friction="1.0"/>
</joint>