TF delay while using TransformBroadcaster?

asked 2018-06-06 23:13:13 -0600

littleghost gravatar image

updated 2018-06-07 04:23:02 -0600

gvdhoorn gravatar image

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: image description 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>
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Comments

It appears the image you have attached isn't working. Can you try attaching it again and perhaps try explaining more what the issue is your having? What do you mean the wheels always lag behind the base? What have you tried so far?

aerotec88 gravatar image aerotec88  ( 2018-06-07 11:16:19 -0600 )edit

Sorry, I don't have enough karma to upload a image. The phenomenon is that the wheels seems broken with the body. To explain that, I analog it in axis, if the body is on 2 now, then the wheels is on 1, and when the body is on 5, then the wheels is on 4. The wheels are chasing the body until I stop.

littleghost gravatar image littleghost  ( 2018-06-07 22:00:09 -0600 )edit

Really like Fugue in the field of music.

littleghost gravatar image littleghost  ( 2018-06-08 04:42:29 -0600 )edit