Include RGB-D Camera into URDF

[yulivee]

https://s3.amazonaws.com/video.udacity-data.com/topher/2018/February/5a820a01_setupa.png/setupa.png.jpeg

Further Resources: Gazebo RGB-D Camera Information http://gazebosim.org/tutorials?tut=ros_gzplugins#DepthCamera

<!-- RGBD Camera -->
  <gazebo reference="camera_link">
    <sensor type="depth" name="camera1">
        <always_on>1</always_on>
        <update_rate>20.0</update_rate>
        <visualize>true</visualize>             
        <camera>
            <horizontal_fov>1.047</horizontal_fov>  
            <image>
                <width>640</width>
                <height>480</height>
                <format>R8G8B8</format>
            </image>
            <depth_camera>

            </depth_camera>
            <clip>
                <near>0.1</near>
                <far>20</far>
            </clip>
        </camera>
             <plugin name="camera_controller" filename="libgazebo_ros_openni_kinect.so">
             <alwaysOn>true</alwaysOn>
                <updateRate>10.0</updateRate>
                <cameraName>camera</cameraName>
                <frameName>camera_rgbd_frame</frameName>                   
            <imageTopicName>rgb/image_raw</imageTopicName>
            <depthImageTopicName>depth/image_raw</depthImageTopicName>
            <pointCloudTopicName>depth/points</pointCloudTopicName>
            <cameraInfoTopicName>rgb/camera_info</cameraInfoTopicName>              
            <depthImageCameraInfoTopicName>depth/camera_info</depthImageCameraInfoTopicName>            
            <pointCloudCutoff>0.4</pointCloudCutoff>                
                <hackBaseline>0.07</hackBaseline>
                <distortionK1>0.0</distortionK1>
                <distortionK2>0.0</distortionK2>
                <distortionK3>0.0</distortionK3>
                <distortionT1>0.0</distortionT1>
                <distortionT2>0.0</distortionT2>
            <CxPrime>0.0</CxPrime>
            <Cx>0.0</Cx>
            <Cy>0.0</Cy>
            <focalLength>0.0</focalLength>
            </plugin>
    </sensor>
  </gazebo>