TF delay while using TransformBroadcaster?

edit

The wheels seems like to have a delay of base_link. I try this tutorial(http://wiki.ros.org/navigation/Tutorials/RobotSetup/Odom) and get a abnormal result. The wheels are always lag behind the base. The picture is: My urdf is:

<?xml version="1.0"?>  
<robot name="my_float_box">  

  <link name="base">  
      <visual>  
        <geometry>  
          <box size="0.25 .16 .05"/>  
      </geometry>  
      <origin rpy="0 0 1.57075" xyz="0 0 0"/>  
      <material name="blue">  
          <color rgba="0 0 .8 1"/>  
      </material>  
      </visual>  
  </link>  

  <link name="right_front_wheel">  
    <visual>  
      <geometry>  
        <cylinder length=".02" radius="0.025"/>  
      </geometry>  
      <material name="black">  
        <color rgba="0 0 0 1"/>  
      </material>  
    </visual>  
  </link>  

  <joint name="right_front_wheel_joint" type="continuous">  
    <axis xyz="0 0 1"/>  
    <parent link="base"/>  
    <child link="right_front_wheel"/>  
    <origin rpy="0 1.57075 0" xyz="0.08 0.1 -0.03"/>  
    <limit effort="100" velocity="100"/>  
    <joint_properties damping="0.0" friction="0.0"/>  
  </joint>  

  <link name="right_back_wheel">  
    <visual>  
      <geometry>  
        <cylinder length=".02" radius="0.025"/>  
      </geometry>  
      <material name="black">  
        <color rgba="0 0 0 1"/>  
      </material>  
    </visual>  
  </link>  

  <joint name="right_back_wheel_joint" type="continuous">  
    <axis xyz="0 0 1"/>  
    <parent link="base"/>  
    <child link="right_back_wheel"/>  
    <origin rpy="0 1.57075 0" xyz="0.08 -0.1 -0.03"/>  
    <limit effort="100" velocity="100"/>  
    <joint_properties damping="0.0" friction="0.0"/>  
</joint>  

<link name="left_front_wheel">  
    <visual>  
      <geometry>  
        <cylinder length=".02" radius="0.025"/>  
      </geometry>  
      <material name="black">  
        <color rgba="0 0 0 1"/>  
      </material>  
    </visual>  
  </link>  

  <joint name="left_front_wheel_joint" type="continuous">  
    <axis xyz="0 0 1"/>  
    <parent link="base"/>  
    <child link="left_front_wheel"/>  
    <origin rpy="0 1.57075 0" xyz="-0.08 0.1 -0.03"/>  
    <limit effort="100" velocity="100"/>  
    <joint_properties damping="0.0" friction="0.0"/>  
  </joint>  

  <link name="left_back_wheel">  
    <visual>  
      <geometry>  
        <cylinder length=".02" radius="0.025"/>  
      </geometry>  
      <material name="black">  
        <color rgba="0 0 0 1"/>  
      </material>  
    </visual>  
  </link>  

  <joint name="left_back_wheel_joint" type="continuous">  
    <axis xyz="0 0 1"/>  
    <parent link="base"/>  
    <child link="left_back_wheel"/>  
    <origin rpy="0 1.57075 0" xyz="-0.08 -0.1 -0.03"/>  
    <limit effort="100" velocity="100"/>  
    <joint_properties damping="0.0" friction="0.0"/>  
  </joint>  

  <link name="head">  
    <visual>  
      <geometry>  
        <box size=".02 .03 .03"/>  
      </geometry>  
      <material name="white">  
          <color rgba="1 1 1 1"/>  
      </material>  
    </visual>  
  </link>  

  <joint name="tobox" type="fixed">  
    <parent link="base"/>  
    <child link="head"/>  
    <origin xyz="0 0.08 0.025"/>  
  </joint>  
</robot>