ROS URDF adds sensor model
Add sensor model
Add camera
The corresponding model file is camera.xacro, which reads as follows

<?xml version="1.0"?>
<robot xmlns:xacro="http://www.ros.org/wiki/xacro" name="camera">

    <xacro:macro name="usb_camera" params="prefix:=camera">
        <link name="${prefix}_link">
            <inertial>
                <mass value="0.1" />
                <origin xyz="0 0 0" />
                <inertia ixx="0.01" ixy="0.0" ixz="0.0"
                         iyy="0.01" iyz="0.0"
                         izz="0.01" />
            </inertial>

            <visual>
                <origin xyz=" 0 0 0 " rpy="0 0 0" />
                <geometry>
                    <box size="0.01 0.04 0.04" />
                </geometry>
                <material name="black"/>
            </visual>

            <collision>
                <origin xyz="0.0 0.0 0.0" rpy="0 0 0" />
                <geometry>
                    <box size="0.01 0.04 0.04" />
                </geometry>
            </collision>
        </link>
    </xacro:macro>

</robot>

The above code USES a macro called USB_camera to describe the camera, and the input parameter is the name of the camera.
Create a top-level XACro file that splicing together the robot and camera modules. The contents of the top-level file mrobot_with_camera.urdf.xacro are as follows, where the contents of the robot ontology description file mrobot_body.urdf.xacro can be found in the previous blog.

<?xml version="1.0"?>
<robot name="mrobot" xmlns:xacro="http://www.ros.org/wiki/xacro">

    <xacro:include filename="$(find mrobot_description)/urdf/mrobot_body.urdf.xacro" />
    <xacro:include filename="$(find mrobot_description)/urdf/camera.xacro" />

    <xacro:property name="camera_offset_x" value="0.1" />
    <xacro:property name="camera_offset_y" value="0" />
    <xacro:property name="camera_offset_z" value="0.02" />

    <!-- MRobot Robotics Platform-->
    <mrobot_body/>

    <!-- Camera -->
    <joint name="camera_joint" type="fixed">
        <origin xyz="${camera_offset_x} ${camera_offset_y} ${camera_offset_z}" rpy="0 0 0" />
        <parent link="plate_2_link"/>
        <child link="camera_link"/>
    </joint>

    <xacro:usb_camera prefix="camera"/>

</robot>

Display the model in RVIz, as shown in the figure below

 roslaunch mrobot_description display_mrobot_with_camera_xacro.launch 

Add it
Kinect is a commonly used RGB-D camera, and the XACro file is shown below

<?xml version="1.0"?>
<robot xmlns:xacro="http://www.ros.org/wiki/xacro" name="kinect_camera">

    <xacro:macro name="kinect_camera" params="prefix:=camera">
        <link name="${prefix}_link">
            <origin xyz="0 0 0" rpy="0 0 0"/>
            <visual>
                <origin xyz="0 0 0" rpy="0 0 ${M_PI/2}"/>
                <geometry>
                    <mesh filename="package://mrobot_description/meshes/kinect.dae" />
                </geometry>
            </visual>
            <collision>
                <geometry>
                    <box size="0.07 0.3 0.09"/>
                </geometry>
            </collision>
        </link>

        <joint name="${prefix}_optical_joint" type="fixed">
            <origin xyz="0 0 0" rpy="-1.5708 0 -1.5708"/>
            <parent link="${prefix}_link"/>
            <child link="${prefix}_frame_optical"/>
        </joint>

        <link name="${prefix}_frame_optical"/>
    </xacro:macro>

</robot>

You can import the mesh file of the model by setting the label in visualization. And then the Kinect and the robot were put together. The top-level Xacro file, mrobot_with_kinet.urdf.xacro, has the following contents

<?xml version="1.0"?>
<robot name="mrobot" xmlns:xacro="http://www.ros.org/wiki/xacro">

    <xacro:include filename="$(find mrobot_description)/urdf/mrobot_body.urdf.xacro" />
    <xacro:include filename="$(find mrobot_description)/urdf/kinect.xacro" />

    <xacro:property name="kinect_offset_x" value="-0.06" />
    <xacro:property name="kinect_offset_y" value="0" />
    <xacro:property name="kinect_offset_z" value="0.035" />

    <!-- MRobot Robotics Platform-->
    <mrobot_body/>

    <!-- Kinect -->
    <joint name="kinect_frame_joint" type="fixed">
        <origin xyz="${kinect_offset_x} ${kinect_offset_y} ${kinect_offset_z}" rpy="0 0 0" />
        <parent link="plate_2_link"/>
        <child link="camera_link"/>
    </joint>
    <xacro:kinect_camera prefix="camera"/>

</robot>

The results displayed in RVIz are shown below

other sensors can be modeled in a similar way.