Making a differential drive robot move

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Hello and thank you for your answer. I have my controller YAML file as follows:

 trs:
  # Publish all joint states -----------------------------------
  joint_state_controller:
    type: joint_state_controller/JointStateController
    publish_rate: 50  

  # Position Controllers ---------------------------------------
  lift_position_controller:
    type: effort_controllers/JointPositionController
    joint: trs_frame_to_lift_joint
    pid: {p: 10000.0, i: 1.00, d: 1000.0}
  rotary_position_controller:
    type: effort_controllers/JointPositionController
    joint: trs_lift_to_rotary_joint
    pid: {p: 100.0, i: 0.01, d: 10.0}
  forks_position_controller:
    type: effort_controllers/JointPositionController
    joint: trs_rotary_to_forks_joint
    pid: {p: 1000.0, i: 0.1, d: 100.0}
  carriage_position_controller:
    type: effort_controllers/JointPositionController
    joint: trs_rotary_to_carriage_joint
    pid: {p: 1000.0, i: 0.1, d: 100.0}

  # Trs base Controller-----------------------------------------
  diff_drive_controller:
    type: "diff_drive_controller/DiffDriveController"
    left_wheel: base_left_wheel_joint
    right_wheel: base_right_wheel_joint
    wheel_separation: 0.46
    wheel_radius: 0.1018
    cmd_vel_timeout: 0.25
    enable_odom_tf: true
    pose_covariance_diagonal: [0.001, 0.001, 1000000.0, 1000000.0, 1000000.0, 1000.0]
    twist_covariance_diagonal: [0.001, 0.001, 1000000.0, 1000000.0, 1000000.0, 1000.0]
    base_frame_id: base_chassis_link

and my launch file as follows:

<launch>
  <arg name="debug" default="false"/>
  <arg name="gui" default="true"/>
  <arg name="paused" default="true"/>

  <!--//////////////////GAZEBO//////////////////-->
  <!-- Include empty world -->
  <include file="$(find gazebo_ros)/launch/empty_world.launch">
    <arg name="world_name" value="$(find trs_gazebo)/worlds/trs.world"/>
    <arg name="debug" value="$(arg debug)"/>
    <arg name="gui" value="$(arg gui)"/>
    <arg name="paused" value="$(arg paused)"/>
  </include>

  <!--//////////////////URDF//////////////////-->
  <!-- Load URDF into the Ros Parameter Server-->
  <param name="robot_description" command="$(find xacro)/xacro --inorder '$(find trs)/trs_with_base.urdf.xacro'"/>

  <!-- Run a python script to send a service call to gazebo_ros to spawn a URDF robot -->
  <node name="urdf_spawner" pkg="gazebo_ros" type="spawn_model" args="-param robot_description -urdf -model trs -robot_namespace trs -J trs_frame_to_lift_joint 1.0" />


  <!--//////////////////JOINT STATE CONTROLLER//////////////////-->
  <!-- load configuration -->
  <rosparam command="load" file="$(find trs_gazebo)/launch/trs_control.yaml" />

  <!-- spawn controllers -->
  <node name="controller_spawner" pkg="controller_manager" type="spawner" respawn="false" output="screen" ns="/trs" args="lift_position_controller rotary_position_controller forks_position_controller carriage_position_controller joint_state_controller diff_drive_controller" /><!-- mobile_base_controller-->

  <!-- Convert joint states to TF transforms -->
  <node name="robot_state_publisher" pkg="robot_state_publisher" type="robot_state_publisher" ns="trs" output="screen"/>

<!--
  <node name="rviz" pkg="rviz" type="rviz" />
-->
</launch>

Also, the .xacro file as it is right now looks as follows:

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

<xacro:macro name="inertia_cylinder" params="mass radius length"> <mass value="${mass}"/> <inertia ixx="${1 / 12 * mass * (3 * radius * radius + length * length)}" ixy="0.0" ixz="0.0" iyy="${1 / 12 * mass * (3 * radius * radius + length * length)}" iyz="0.0" izz="${mass * radius * radius / 2}"/> </xacro:macro>

<xacro:macro name="trs_base" params="prefix">

<!--gazebo reference="robot">
  <material>Gazebo/Orange</material>
</gazebo-->
<!--gazebo reference="${prefix}chassis_link">
  <material>Gazebo/Orange</material>
</gazebo-->
<gazebo reference="${prefix}left_wheel_link">
  <material>Gazebo/Orange</material>
</gazebo>
<gazebo reference="${prefix}right_wheel_link">
  <material>Gazebo/Orange</material>
</gazebo>

<link name="robot"/>
<joint name="${prefix}robot_to_chassis" type="fixed">
  <parent link="robot"/>
  <child link="${prefix}chassis_link"/>
  <origin rpy="0 0 0" xyz="0 0 0"/>
</joint>

<link name="${prefix}chassis_link">
  <inertial>
    <mass value="120.911"/>
    <origin rpy="0 0 0" xyz="-0.1832 0.0 0.15"/>
    <inertia ixx="3.50889411882" ixy="0.0" ixz="0.0" iyy="9.06900169571" iyz="0.0" izz="11.7718257055"/>
  </inertial>
  <collision name ...