suspension_wheel.urdf parameters

[menson168]

Hi, I am trying to use the rbcar_sim to test out some other Ackermann steered vehicle as well and I encountered some suspension geometry problem as I was customizing the suspension setup. Can you explain what each of the parameters means in the suspension_wheel.urdf.xacro?

<xacro:property name="hex_hub_depth" value="0.12"/> <!-- or +0.072 -->

  <!-- hex_hub_dist is the distance between left and right hex hubs when
       the shock absorbers are fully extended. axle_length is the distance
       from a U joint to the corresponding hex hub. wheel_travel is the
       vertical wheel travel. -->
  <xacro:property name="wheelbase" value="1.650"/>
  <xacro:property name="hex_hub_dist" value="0.900"/>  <!-- 1.127 0.742 0.900 check -->
  <xacro:property name="axle_length" value="0.120"/>
  <xacro:property name="wheel_travel" value="0.1"/>
  <xacro:property name="shock_z_offset" value="0.05"/>

I don't quite get the documentation listed in the code. Is it possible if you can clarify things up a bit?
Thanks.