ROS rviz gazebo No transform from [left_leg] to [base_link]

http://wiki.ros.org/urdf/Tutorials/Building%20a%20Movable%20Robot%20Model%20with%20URDF

 

当出现这种现象时，是因为joint_state_publisher没有启动。

在launch中添加joint_state_publisher 和robot_state_publisher会正常。

<launch>

  <!-- these are the arguments you can pass this launch file, for example paused:=true
<arg name="model" default="04-materials.urdf"/>
 -->
  <arg name="paused" default="false"/>
  <arg name="use_sim_time" default="true"/>
  <arg name="gui" default="true"/>
  <arg name="headless" default="false"/>
  <arg name="debug" default="false"/>
  

  <arg name="model" default="04-materials.urdf"/>


  <!-- We resume the logic in empty_world.launch, changing only the name of the world to be launched -->
  <include file="$(find gazebo_ros)/launch/empty_world.launch">
    <arg name="debug" value="$(arg debug)" />
    <arg name="gui" value="$(arg gui)" />
    <arg name="paused" value="$(arg paused)"/>
    <arg name="use_sim_time" value="$(arg use_sim_time)"/>
    <arg name="headless" value="$(arg headless)"/>
  </include>

  <param name="robot_description" command="$(find xacro)/xacro --inorder $(arg model)" />
 
  <!-- push robot_description 
   <param name="robot_description" command="$(find xacro)/xacro.py $(arg model)" />

  to factory and spawn robot in gazebo -->
  <node name="urdf_spawner" pkg="gazebo_ros" type="spawn_model"
        args="-z 1.0 -unpause -urdf -model robot -param robot_description" respawn="false" output="screen" />

  <node pkg="robot_state_publisher" type="robot_state_publisher"  name="robot_state_publisher">
    <param name="publish_frequency" type="double" value="30.0" />
  </node>

   <node name="joint_state_publisher" pkg="joint_state_publisher" type="joint_state_publisher" />

   <node name="my_controller_spawner" pkg="controller_manager" type="spawner" respawn="false"
	output="screen" args="my_controller_name"/>


</launch>

<?xml version="1.0"?>
<robot name="materials" xmlns:xacro="http://ros.org/wiki/xacro">
 
  <xacro:macro name="default_inertial" params="mass">
    <inertial>
      <mass value="${mass}" />
      <inertia ixx="1.0" ixy="0.0" ixz="0.0" iyy="1.0" iyz="0.0" izz="1.0" />
    </inertial>
  </xacro:macro>
  <material name="blue">
    <color rgba="0 0 0.8 1"/>
  </material>

  <material name="white">
    <color rgba="1 1 1 1"/>
  </material>

  <link name="base_link">
    <visual>
      <geometry>
        <cylinder length="0.1" radius="0.6"/>
      </geometry>
      <material name="blue"/>
    </visual>

        <collision>
      <geometry>
        <cylinder  length="0.1" radius="0.6"/>
      </geometry>
    </collision>
    <xacro:default_inertial mass="10"/>

  </link>

  <link name="right_leg">
    <visual>
      <geometry>
       <cylinder length="0.05" radius="0.2"/>
      </geometry>
      <origin rpy="1.5707963267948966 0 0" xyz="0 -0 0"/>
      <material name="white"/>
    </visual>

            <collision>
      <geometry>
        <cylinder length="0.05" radius="0.2"/>
      </geometry>
    </collision>
    <xacro:default_inertial mass="10"/>

  </link>

  <joint name="base_to_right_leg" type="continuous">
    <parent link="base_link"/>
    <child link="right_leg"/>
<axis xyz="0 0 1" />
    <origin rpy="0 0 0" xyz="0 -0.6 0"/>

  </joint>

  <link name="left_leg">
    <visual>
      <geometry>
        <cylinder length="0.05" radius="0.2"/>
      </geometry>
      <origin rpy="1.5707963267948966 0 0" xyz="0 0. 0"/>
      <material name="white"/>
     
    </visual>
      <collision>
      <geometry>
        <cylinder length="0.05" radius="0.2"/>
      </geometry>
    </collision>
    <xacro:default_inertial mass="10"/>
  </link>

  <gazebo reference="right_leg">
    <material>Gazebo/Orange</material>
  </gazebo>

  <joint name="base_to_left_leg" type="continuous">
    <parent link="base_link"/>
    <child link="left_leg"/>
<axis xyz="0 0 1" />
    <origin rpy="0 0 0" xyz="0 0.6 0"/>

  </joint>

 <!-- stereo camera -->
    <gazebo reference="base_link">  
      <sensor type="multicamera" name="stereocamera">
        <always_on>true</always_on>
        <update_rate>10</update_rate>
        <visualize>false</visualize>
        <camera name="left">
          <pose>0 0 0 0 0 0</pose>
          <horizontal_fov>1.047</horizontal_fov>
          <image>
            <width>320</width>
            <height>240</height>
          </image>
          <clip>
            <near>0.1</near>
            <far>100</far>
          </clip>
        </camera>
        <camera name="right">
          <pose>0 -0.07 0 0 0 0</pose>
          <horizontal_fov>1.047</horizontal_fov>
          <image>
            <width>320</width>
            <height>240</height>
          </image>
          <clip>
            <near>0.1</near>
            <far>100</far>
          </clip>
        </camera> 


       
        <plugin name="stereo_camera_controller" filename="libgazebo_ros_multicamera.so">
          <cameraName>stereocamera</cameraName>
          <alwaysOn>true</alwaysOn>
          <updateRate>10</updateRate>
          <cameraName>stereocamera</cameraName>
          <imageTopicName>image_raw</imageTopicName>
          <cameraInfoTopicName>camera_info</cameraInfoTopicName>
          <frameName>camera_link_optical</frameName>
          <baseline>0.07</baseline>
          <distortion_k1>0.0</distortion_k1>
          <distortion_k2>0.0</distortion_k2>
          <distortion_k3>0.0</distortion_k3>
          <distortion_t1>0.0</distortion_t1>
          <distortion_t2>0.0</distortion_t2>
        </plugin>
      </sensor>
    </gazebo>
 

  <transmission name="base_to_left_leg_joint_trans">
    <type>transmission_interface/SimpleTransmission</type>
    <joint name="base_to_left_legjoint"/>
    <actuator name="base_to_left_leg_joint_motor">
      <hardwareInterface>PositionJointInterface</hardwareInterface>
      <mechanicalReduction>1</mechanicalReduction>
    </actuator>
  </transmission>


  <transmission name="base_to_right_leg_joint_trans">
    <type>transmission_interface/SimpleTransmission</type>
    <joint name="base_to_right_legjoint"/>
    <actuator name="base_to_right_leg_joint_motor">
      <hardwareInterface>PositionJointInterface</hardwareInterface>
      <mechanicalReduction>1</mechanicalReduction>
    </actuator>
  </transmission>

 <gazebo>
    <plugin filename="libgazebo_ros_diff_drive.so" name="differential_drive_controller_front">
      <rosDebugLevel>Debug</rosDebugLevel>
      <publishWheelTF>True</publishWheelTF>
      <publishTf>1</publishTf>
      <publishWheelJointState>true</publishWheelJointState>
      <alwaysOn>true</alwaysOn>
      <updateRate>100.0</updateRate>
      <leftJoint>base_to_left_leg</leftJoint>
      <rightJoint>base_to_right_leg</rightJoint>
      <wheelSeparation>0.3</wheelSeparation>
      <wheelDiameter>0.08</wheelDiameter>
      <broadcastTF>1</broadcastTF>
      <wheelTorque>30</wheelTorque>
      <wheelAcceleration>1.8</wheelAcceleration>
      <commandTopic>cmd_vel</commandTopic>
      <odometryFrame>odom</odometryFrame>
      <odometryTopic>odom</odometryTopic>
      <robotBaseFrame>base_link</robotBaseFrame>
    </plugin>
  </gazebo>
<gazebo>
    <plugin name="gazebo_ros_control" filename="libgazebo_ros_control.so">
      <robotNamespace>/</robotNamespace>
    </plugin>
  </gazebo>
</robot>

正常了。