Hi. I'm new to ROS and Gazebo simulation. I tried to create a differential drive robot for various experiments such sa SLAM etc.

I have set my joint to rotate on the y-axis as setting them on x or z makes them move weird. But when I try to make my robot move forward using teleop, the wheels move vertically instead of horizontally.

Tried on Ubuntu 18.04 LTS, ROS Melodic, Gazebo 9 and 20.04 LTS, ROS Noetic, Gazebo 11

EDIT: Added yaml code

EDIT2: Added launch code

Here is the relevant part of my urdf:

 <link name="base_link">
 </link>

<joint name="base_joint" type="fixed">
    <parent link="base_link"/>
    <child link="chassis"/>
</joint>

<link name="chassis">

    <inertial>
        <origin xyz="0.0 0.0 0.0" rpy="0.0 0.0 0.0"/>
        <mass value="25"/>
        <inertia ixx="3.002" ixy="0.0" ixz="0.0" iyy="4.011" iyz="0.0" izz="2.8465"/>
    </inertial>
    <visual name="chassis_visual">
        <origin xyz="0.0 0.0 0.0" rpy="0.0 0.0 0.0"/>
        <geometry>
            <box size="0.962 0.664 1" />
        </geometry>
    </visual>
    <collision name="chassis_collision">
        <origin xyz="0.0 0.0 0.0" rpy="0.0 0.0 0.0"/>
        <geometry>
            <box size="0.962 0.664 1" />
        </geometry>
    </collision>
</link>

<link name="front_left_wheel">
    <inertial>
        <origin xyz="0.3 0.232 -0.525" rpy="1.5707 0.0 0.0"/>
        <mass value="5"/>
        <inertia ixx="0.02" ixy="0.0" ixz="0.0" iyy="0.02" iyz="0.0" izz="0.02"/>
    </inertial>
   <visual name="front_left_wheel_visual">
        <origin xyz="0.3 0.232 -0.525" rpy="1.5707 0.0 0.0"/>
        <geometry>
            <cylinder radius="0.1" length="0.1"/>
        </geometry>
    </visual>
    <collision name="front_left_wheel_collision">
        <origin xyz="0.3 0.232 -0.525" rpy="1.5707 0.0 0.0"/>
        <geometry>
            <cylinder radius="0.1" length="0.1"/>
        </geometry>
    </collision>
</link>

<link name="front_right_wheel">
    <inertial>
        <origin xyz="0.3 -0.232 -0.525" rpy="1.5707 0.0 0.0"/>
        <mass value="5"/>
        <inertia ixx="0.02" ixy="0.0" ixz="0.0" iyy="0.02" iyz="0.0" izz="0.02"/>
    </inertial>
    <visual name="front_right_wheel_visual">
        <origin xyz="0.3 -0.232 -0.525" rpy="1.5707 0.0 0.0"/>
        <geometry>
            <cylinder radius="0.1" length="0.1"/>
        </geometry>
    </visual>
    <collision name="front_right_wheel_collision">
        <origin xyz="0.3 -0.232 -0.525" rpy="1.5707 0.0 0.0"/>
        <geometry>
            <cylinder radius="0.1" length="0.1"/>
        </geometry>
    </collision>
</link>

<link name="rear_left_wheel">
    <inertial>
        <origin xyz="-0.3 0.232 -0.525" rpy="1.5707 0.0 0.0"/>
        <mass value="5"/>
        <inertia ixx="0.02" ixy="0.0" ixz="0.0" iyy="0.02" iyz="0.0" izz="0.02"/>
    </inertial>
    <visual name="rear_left_wheel_visual">
        <origin xyz="-0.3 0.232 -0.525" rpy="1.5707 0.0 0.0"/>
        <geometry>
            <cylinder radius="0.1" length="0.1"/>
        </geometry>
    </visual>
    <collision name="rear_left_wheel_collision">
        <origin xyz="-0.3 0.232 -0.525" rpy="1.5707 0.0 0.0"/>
        <geometry>
            <cylinder radius="0.1" length="0.1"/>
        </geometry>
    </collision>
</link>

<link name="rear_right_wheel">
    <inertial>
        <origin xyz="-0.3 -0.232 -0.525" rpy="1.5707 0.0 0.0"/>
        <mass value="5"/>
        <inertia ixx="0.02" ixy="0.0" ixz="0.0" iyy="0.02" iyz="0.0" izz="0.02"/>
    </inertial>
    <visual name="rear_right_wheel_visual">
        <origin xyz="-0.3 -0.232 -0.525" rpy="1.5707 0.0 0.0"/>
        <geometry>
            <cylinder radius="0.1" length="0.1"/>
        </geometry>
    </visual>
    <collision name="rear_right_wheel_collision">
        <origin xyz="-0.3 -0.232 -0.525" rpy="1.5707 0.0 0.0"/>
        <geometry>
            <cylinder radius="0.1" length="0.1"/>
        </geometry>
    </collision>
</link>

<joint name="front_left_wheel_hinge" type="continuous">
    <origin xyz="0.0 0.0 0.0" rpy="0.0 0.0 0.0"/>
    <parent link="chassis"/>
    <child link="front_left_wheel"/>
    <axis xyz="0.0 1.0 0.0"/>
    <limit effort="100" velocity="100"/>
</joint>

<joint name="front_right_wheel_hinge" type="continuous">
    <origin xyz="0.0 0.0 0.0" rpy="0.0 0.0 0.0"/>
    <parent link="chassis"/>
    <child link="front_right_wheel"/>
    <axis xyz="0.0 1.0 0.0"/>
    <limit effort="100" velocity="100"/>
</joint>

<joint name="rear_left_wheel_hinge" type="fixed">
    <origin xyz="0.0 0.0 0.0" rpy="0.0 0.0 0.0"/>
    <parent link="chassis"/>
    <child link="rear_left_wheel"/>
    <axis xyz="0.0 1.0 0.0"/>
    <dynamics friction="0.0" />
    <limit lower="0.0" upper="0.0" effort="100" velocity="100"/>
</joint>

<joint name="rear_right_wheel_hinge" type="fixed">
    <origin xyz="0.0 0.0 0.0" rpy="0.0 0.0 0.0"/>
    <parent link="chassis"/>
    <child link="rear_right_wheel"/>
    <axis xyz="0.0 1.0 0.0"/>
    <dynamics friction="0.0" />
    <limit lower="0.0" upper="0.0" effort="100" velocity="100"/>
</joint>

<gazebo>
    <plugin name="gazebo_ros_control" filename="libgazebo_ros_control.so">
    <robotNamespace>/test_robot</robotNamespace> -->
    </plugin>
</gazebo>

<transmission name="chassis_to_front_left_wheel_transmission">
    <type>transmission_interface/SimpleTransmission</type>
    <actuator name="motor1">
        <hardwareInterface>hardware_interface/VelocityJointInterface</hardwareInterface>
        <mechanicalReduction>1</mechanicalReduction>
    </actuator>
    <joint name="front_left_wheel_hinge">
        <hardwareInterface>hardware_interface/VelocityJointInterface</hardwareInterface>
    </joint>
</transmission>

<transmission name="chassis_to_front_right_wheel_transmission">
    <type>transmission_interface/SimpleTransmission</type>
    <actuator name="motor2">
        <hardwareInterface>hardware_interface/VelocityJointInterface</hardwareInterface>
        <mechanicalReduction>1</mechanicalReduction>
    </actuator>
    <joint name="front_right_wheel_hinge">
        <hardwareInterface>hardware_interface/VelocityJointInterface</hardwareInterface>
    </joint>
</transmission>

<gazebo>
    <plugin name="differential_drive_controller" filename="libgazebo_ros_diff_drive.so">
        <updateRate>20</updateRate>
        <leftJoint>front_left_wheel_hinge</leftJoint>
        <rightJoint>front_right_wheel_hinge</rightJoint>
        <wheelSeparation>0.464</wheelSeparation>
        <wheelDiameter>0.2</wheelDiameter>
        <wheelAcceleration>1.0</wheelAcceleration>
        <wheelTorque>20</wheelTorque>
        <commandTopic>/test_robot/diff_drive_controller/cmd_vel</commandTopic>
        <odometryTopic>/test_robot/diff_drive_controller/odom</odometryTopic>
        <odometryFrame>/test_robot/diff_drive_controller/odom</odometryFrame>
        <robotBaseFrame>base_link</robotBaseFrame>
        <odometrySource>1</odometrySource>
        <publishWheelTF>true</publishWheelTF>
        <publishOdom>true</publishOdom>
        <publishWheelJointState>true</publishWheelJointState>
        <legacyMode>false</legacyMode>
    </plugin>
</gazebo>

Here is my yaml code:

test_robot:
  joint_state_controller:
    type: joint_state_controller/JointStateController
    publish_rate: 50

  diff_drive_controller:
    type        : "diff_drive_controller/DiffDriveController"
    left_wheel  : 'front_left_wheel_hinge'
    right_wheel : 'front_right_wheel_hinge'
    publish_rate: 50.0               # default: 50
    pose_covariance_diagonal : [0.0, 0.0, 0.0, 0.0, 0.0, 0.0]
    twist_covariance_diagonal: [0.0, 0.0, 0.0, 0.0, 0.0, 0.0]

    # Wheel separation and diameter. These are both optional.
    # diff_drive_controller will attempt to read either one or both from the
    # URDF if not specified as a parameter
    wheel_separation : 0.464
    wheel_radius : 0.1

    # Wheel separation and radius multipliers
    wheel_separation_multiplier: 1.0 # default: 1.0
    wheel_radius_multiplier    : 1.0 # default: 1.0

    # Velocity commands timeout [s], default 0.5
    cmd_vel_timeout: 0.25

    # Base frame_id
    base_frame_id: chassis #default: base_link

    # Velocity and acceleration limits
    # Whenever a min_* is unspecified, default to -max_*
    linear:
      x:
        has_velocity_limits    : true
        max_velocity           : 1.0  # m/s
        min_velocity           : -0.5 # m/s
        has_acceleration_limits: true
        max_acceleration       : 0.8  # m/s^2
        min_acceleration       : -0.4 # m/s^2
        has_jerk_limits        : true
        max_jerk               : 5.0  # m/s^3
    angular:
      z:
        has_velocity_limits    : true
        max_velocity           : 1.7  # rad/s
        has_acceleration_limits: true
        max_acceleration       : 1.5  # rad/s^2
        has_jerk_limits        : true
        max_jerk               : 2.5  # rad/s^3

Here is the launch code:

 <launch>

  <include file="$(find gazebo_ros)/launch/empty_world.launch">
    <arg name="world_name" value="$(find test_robot_gazebo)/worlds/test_robot.world"/>
  </include>

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

  <param name="robot_description" textfile="$(find test_robot_description)/model/test_robot.urdf" />

  <node name="spawn_urdf" pkg="gazebo_ros" type="spawn_model" args="-file $(find test_robot_description)/model/test_robot.urdf -urdf -z 1 -model test_robot" />

  <rosparam file="$(find test_robot_description)/config/diff_drive.yaml" command="load" />
  <node name="controller_spawner" pkg="controller_manager" type="spawner" respawn="false" output="screen" ns="/test_robot" args="joint_state_controller diff_drive_controller" />
    <remap from="/cmd_vel" to="/test_robot/diff_drive_controller/cmd_vel" />

  <rosparam file="$(find test_robot_description)/config/gazebo_ros_control_params.yaml" command="load"/>

  <arg name="gui" default="True" />
   <param name="use_gui" value="True"/>
   <node name="joint_state_publisher" pkg="joint_state_publisher" type="joint_state_publisher" />
   <node name="robot_state_publisher" pkg="robot_state_publisher" type="robot_state_publisher" respawn="false" output="screen" />
    <remap from="/joint_states" to="/test_robot/joint_states" />


</launch>