Questions about cartographer with urdf : param robot_description not found by searchParam()

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Recently I'm trying to make a mobile robot with cartographer, & rplidar_a3. I finished to use my rplidar with cartographer with the commands(by googling).

roslaunch rplidar_ros view_rplidar_a3.launch roslaunch cartographer_ros rplidar_2d.launch

And fortunately, it worked well. so I thought that the next step should be murging rplidar_2d.launch with my urdf. And I've tried it but I couldn't visualize my urdf on rviz with an error msg like this

param robot_description not found by searchParam()

And also, I cannot found robot_state_publisher() on my rqt tf tree.

My modified rplidar_2d.launch and rplidar.lua files are like this.

<launch>

  <param name="robot_description"
    textfile="$(find cartographer_ros)/urdf/qs_bot.xacro"/>

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

  <node pkg="cartographer_ros" type="cartographer_node" name="cartographer_node"
    args="-configuration_directory $(find cartographer_ros)/configuration_files
    -configuration_basename rplidar.lua"
    output="screen">
    <remap from="echoes" to="scan" />
  </node>

  <node pkg="cartographer_ros" type="cartographer_occupancy_grid_node"
     name="cartographer_occupancy_grid_node"
     args="-resolution 0.05" />

  <!-- AMCL -->
  <!-- <node pkg="amcl" type="amcl" name="amcl" args="scan:=scan">
    <remap from="static_map" to="/static_map"/>
    <param name="initial_pose_x" value="$(arg x_pos)" />
    <param name="initial_pose_y" value="$(arg y_pos)" />
    <param name="global_frame_id" value="map" />
    <param name="odom_frame_id" value="$(arg robot_name)/odom" />
    <param name="base_frame_id" value="$(arg robot_name)/base_link" />
  </node> -->

  <node name="rviz" pkg="rviz" type="rviz" required="true"
    args="-d $(find cartographer_ros)/configuration_files/demo_2d.rviz" />

</launch>

lua file

include "map_builder.lua" include "trajectory_builder.lua"

options = {
    map_builder = MAP_BUILDER,
    trajectory_builder = TRAJECTORY_BUILDER,
    map_frame = "map",
    tracking_frame = "base_link",
    published_frame = "base_link",
    odom_frame = "odom",
    provide_odom_frame = true,
    publish_frame_projected_to_2d = false,
    use_pose_extrapolator = true,
    use_odometry = false,
    use_nav_sat = false,
    use_landmarks = false,
    num_laser_scans = 1,
    num_multi_echo_laser_scans = 0,
    num_subdivisions_per_laser_scan = 10,
    num_point_clouds = 0,
    lookup_transform_timeout_sec = 0.2,
    submap_publish_period_sec = 0.3,
    pose_publish_period_sec = 5e-3,
    trajectory_publish_period_sec = 30e-3,
    rangefinder_sampling_ratio = 1.,
    odometry_sampling_ratio = 1,
    fixed_frame_pose_sampling_ratio = 1,
    imu_sampling_ratio = 1,
    landmarks_sampling_ratio = 1,
}

MAP_BUILDER.use_trajectory_builder_2d = true
TRAJECTORY_BUILDER_2D.use_imu_data = false
TRAJECTORY_BUILDER_2D.use_online_correlative_scan_matching = true
POSE_GRAPH.optimization_problem.huber_scale = 1e2

return options

And my urdf(.xacro) files are like this.

<robot <a="" href="http://xmlns:xacro="http://www.ros.org/wiki/xacro">xmlns:xacro="http://www.ros.org/wiki/..." name="qs_bot"></robot>

  <!-- colors -->
  <material name="black">
    <color rgba="0 0 0 1"/>
  </material>
  <material name="white">
    <color rgba="1 1 1 1"/>
  </material>
  <material name="green">
    <color rgba="0 1 0 1"/>
  </material>

  <xacro:macro name="Transmission_block" params="joint_name">
    <transmission name="${joint_name}_trans">
    <type>transmission_interface/SimpleTransmission</type>
      <joint name="${joint_name}">
         <hardwareInterface>PositionJointInterface</hardwareInterface>
      </joint>
    <actuator name="${joint_name}_motor">
      <mechanicalReduction>1</mechanicalReduction>
    </actuator>
    </transmission>
  </xacro:macro>

  <!-- xacro parameters -->
  <xacro:property name="joint_wheel_match" value="-0.053 0.02 -0.052" />
  <xacro:property name="center_to_left_dis" value="0.2175" />
  <xacro:property name="center_to_right_dis" value="-${center_to_left_dis}" />
  <xacro:property name="center_to_front_dis" value="0.176" />
  <xacro:property name="center_to_back_dis" value="-0.169" />
  <xacro:property name="wheel_mass" value="0.8" />
  <xacro:property name="wheel_height" value="-0.085" />
  <!-- <xacro:property name="wheel_width" value="0.03552" /> -->
  <xacro:property name ...