ros2 foxy gazebo中加载世界以及机器

最新推荐文章于 2025-04-21 08:55:55 发布

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最新推荐文章于 2025-04-21 08:55:55 发布

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分类专栏： ros2 gazebo

本文链接：https://blog.youkuaiyun.com/weixin_42454034/article/details/106994154

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ros2中gazebo加载机器人的方式与ros1中有很大不同,一共有三种方式加载模型.
#使用-file 打开sdf文件
#使用-database需要先将模型路径添加到GAZEBO_MODEL_PATH ‘export GAZEBO_MODEL_PATH=$GAZEBO_MODEL_PATH:model_path’ 而且模型需要参照gazebo中的标准写法才能成功加载
#使用-topic订阅机器人话题话题由robot_state_publisher发布其打开的是urdf文件

最后打开gazebo的.py文件如下:

import os
from launch import LaunchDescription
from launch.actions import IncludeLaunchDescription
from launch.launch_description_sources import PythonLaunchDescriptionSource
from launch.substitutions import ThisLaunchFileDir
from launch_ros.actions import Node
from ament_index_python.packages import get_package_share_directory
from launch.actions import ExecuteProcess
from launch.substitutions import LaunchConfiguration

def generate_launch_description():
    gazebo_dir = os.path.join(get_package_share_directory('gazebo_ros'),'launch')
    # world = os.path.join(get_package_share_directory('gis_gazebo'), 'worlds', 'test.world')

    urdf = os.path.join(
        get_package_share_directory('gis_gazebo'),
        'urdf','gis_car.urdf')

    model_path = os.path.join(
        get_package_share_directory('gis_gazebo'),
        'models','pipe1.sdf')

    use_sim_time = LaunchConfiguration('use_sim_time', default=True) 

    return LaunchDescription([
        #退出gazebo时gzserver经常关不掉，所以打开gazebo前先关掉gzserver
        ExecuteProcess(
            cmd=['killall','-q', 'gzserver'],
            output='screen'),
        ExecuteProcess(
            cmd=['killall','-q', 'gzclient'],
            output='screen'),

        IncludeLaunchDescription(
            PythonLaunchDescriptionSource([gazebo_dir, '/gzserver.launch.py']),
            # launch_arguments={
            #     'world': world
            #     }.items(),
        ),
        

        IncludeLaunchDescription(
            PythonLaunchDescriptionSource([gazebo_dir ,'/gzclient.launch.py'])),


        #使用-file 打开sdf文件 
        #使用-database需要先将模型路径添加到GAZEBO_MODEL_PATH  'export GAZEBO_MODEL_PATH=$GAZEBO_MODEL_PATH:model_path'  而且模型需要参照gazebo中的标准写法才能成功加载
        #使用-topic订阅机器人话题 话题由robot_state_publisher发布  其打开的是urdf文件
        Node(package='gazebo_ros', node_executable='spawn_entity.py',
                        arguments=[
                            '-x','0.0',
                            '-y','0.0',
                            '-z','2.0',
                            '-Y','0.0',  #yaw
                            '-entity', 'car',   #gazebo中机器命名
                            # '-database', 'cardboard_box',
                            # '-file',model_path,
                            '-topic','robot_description',
                            ],
                        output='screen'),

        Node(
            package='robot_state_publisher',
            node_executable='robot_state_publisher',
            node_name='robot_state_publisher',
            output='screen',
            parameters=[{'use_sim_time': use_sim_time},
                {'publish_frequency':100.0},
                ],
            arguments=[urdf]
            ),

    ])

其中 world模型可以先打开gazebo,随意创建模型后另存为world.

urdf文件如下:

<?xml version ="1.0"?>
<robot xmlns:controller="http://playerstage.sourceforge.net/gazebo/xmlschema/#controller"
  xmlns:interface="http://playerstage.sourceforge.net/gazebo/xmlschema/#interface"
  xmlns:sensor="http://playerstage.sourceforge.net/gazebo/xmlschema/#sensor"
  xmlns:xacro="http://ros.org/wiki/xacro"
  name="ghost" >

<!-- Included URDF/XACRO Files -->
<!-- <xacro:include filename="$(find sick_scan)/urdf/example.urdf.xacro" /> -->
 
<link name="base_link">
 <visual>
     <geometry>
       <box size="0.25 0.16 0.15"/>
     </geometry>
     <material name="sliver">
       <color rgba="0.75 0.75 0.75 1"/>
     </material>
   </visual>
  <!--碰撞大小-->
   <collision>
      <geometry>
       <box size="0.25 0.16 0.15"/>
     </geometry> 
   </collision>
  <!--物理信息-->
   <inertial>
     <mass value="0.2"/>
     <inertia ixx="0.5" iyy="0.75" izz="0.75"
              ixy="0" ixz="0" iyz="0" />
   </inertial>
</link>
 
 
<link name="fl_wheel">
  <visual>
     <geometry>
      <cylinder length="0.05" radius="0.05"/>
     </geometry>
     <material name="black">     
     </material>
   </visual>

   <collision>
      <geometry>
       <cylinder length="0.05" radius="0.05"/>
     </geometry>
   </collision>

   <inertial>
     <mass value="0.1"/>
     <inertia ixx="0.083" iyy="0.083" izz="0.0167"
              ixy="0" ixz="0" iyz="0" />
   </inertial>
  </link>

 <link name="fr_wheel">
 <visual>
     <geometry>
      <cylinder length="0.05" radius="0.05"/>
     </geometry>
     <material name="black">     
     </material>
   </visual>

   <collision>
      <geometry>
       <cylinder length="0.05" radius="0.05"/>
     </geometry>
   </collision>

   <inertial>
     <mass value="0.1"/>
     <inertia ixx="0.083" iyy="0.083" izz="0.0167"
              ixy="0" ixz="0" iyz="0" />
   </inertial>
  </link>

 <link name="bl_wheel">
  <visual>
     <geometry>
      <cylinder length="0.05" radius="0.05"/>
     </geometry>
     <material name="black">     
     </material>
   </visual>

   <collision>
      <geometry>
       <cylinder length="0.05" radius="0.05"/>
     </geometry>
   </collision>

   <inertial>
     <mass value="0.1"/>
     <inertia ixx="0.083" iyy="0.083" izz="0.0167"
              ixy="0" ixz="0" iyz="0" />
   </inertial>
  </link>

 <link name="br_wheel">
  <visual>
     <geometry>
      <cylinder length="0.05" radius="0.05"/>
     </geometry>
     <material name="black">     
     </material>
   </visual>

   <collision>
      <geometry>
       <cylinder length="0.05" radius="0.05"/>
     </geometry>
   </collision>

   <inertial>
     <mass value="0.1"/>
     <inertia ixx="0.083" iyy="0.083" izz="0.0167"
              ixy="0" ixz="0" iyz="0" />
   </inertial>
  </link>

 <joint name="fl_joint" type="continuous">
  <axis xyz="0 0 1"/>
  <parent link="base_link"/>
  <child link="fl_wheel"/>
  <origin rpy="-1.57 0 0" xyz="0.105 -0.0772 -0.05"/>
 </joint>

 <joint name="fr_joint" type="continuous">
  <axis xyz="0 0 1"/>
  <parent link="base_link"/>
  <child link="fr_wheel"/>
  <origin rpy="-1.57 0 0" xyz="0.105 0.0772 -0.05"/>
 </joint>

 <joint name="bl_joint" type="continuous">
  <axis xyz="0 0 1"/>
  <parent link="base_link"/>
  <child link="bl_wheel"/>
  <origin rpy="-1.57 0 0" xyz="-0.105 -0.0772 -0.05"/>
 </joint>

 <joint name="br_joint" type="continuous">
  <axis xyz="0 0 1"/>
  <parent link="base_link"/>
  <child link="br_wheel"/>
  <origin rpy="-1.57 0 0" xyz="-0.105 0.0772 -0.05"/>
 </joint>


<!--添加激光传感器-->
<!--激光位置-->
<link name="scan_link">
  
</link>

<joint name="scan_joint" type="fixed">
  <axis xyz=" 0 1 0"/>
  <origin xyz="0.0 0.0 0.2" rpy="0 0 0"/>
  <parent link="base_link"/>
  <child link="scan_link"/>
</joint>

<link name="imu_link">
  
</link>

<joint name="imu_joint" type="fixed">
  <axis xyz=" 0 1 0"/>
  <origin xyz="0.0 0.0 0" rpy="0 0 0"/>
  <parent link="base_link"/>
  <child link="imu_link"/>
</joint>

<!--全向移动  -->
<gazebo>
    <plugin name="object_controller" filename="libgazebo_ros_planar_move.so">
      <commandTopic>cmd_vel</commandTopic>
      <odometryTopic>odom</odometryTopic>
      <odometryFrame>odom</odometryFrame>
      <odometryRate>100.0</odometryRate>
      <robotBaseFrame>base_link</robotBaseFrame>
      <broadcastTF>true</broadcastTF>
    </plugin>
</gazebo>

 <gazebo reference="imu_link">
    <gravity>true</gravity>
    <sensor name="imu_sensor" type="imu">
      <always_on>true</always_on>
      <update_rate>100</update_rate>
      <!--<visualize>true</visualize>-->
      <topic>__default_topic__</topic>
      <plugin filename="libgazebo_ros_imu_sensor.so" name="imu_plugin">
        <topicName>imu</topicName>
        <bodyName>base_link</bodyName>
        <updateRateHZ>100.0</updateRateHZ>
        <gaussianNoise>0.0</gaussianNoise>
        <xyzOffset>0 0 0</xyzOffset>
        <rpyOffset>0 0 0</rpyOffset>
        <frameName>imu_link</frameName>
      </plugin>
      <pose>0 0 0 0 0 0</pose>
    </sensor>
  </gazebo>

<!--激光雷达-->
<gazebo reference="scan_link">
    <!--虚拟机无法使用GPU-->
  <sensor type="ray" name="tim561">  
    <pose>0 0 0 0 0 0 </pose>
    <visualize>true</visualize>
    <update_rate>20</update_rate>
    <ray>
      <scan>
        <horizontal>
          <samples>360</samples>
          <resolution>1</resolution>
          <min_angle>-2.093</min_angle>
          <max_angle>2.093</max_angle>
        </horizontal>
      </scan>

      <range>
        <min>0.3</min>
        <max>10</max>
        <resolution>0.01</resolution>
      </range>
      <noise>
          <type>gaussian</type>
          <mean>0.0</mean>
          <stddev>0.005</stddev>
      </noise>
    </ray>
    
    <plugin name="gazebo_ros_controller" filename="libgazebo_ros_laser.so">
    <!--<plugin name="gpu_laser" filename="libgazebo_ros_laser.so">-->
      <topicName>/scan</topicName>
      <frameName>scan_link</frameName>
    </plugin>

    <plugin name="gazebo_ros_joint_state_publisher"
        filename="libgazebo_ros_joint_state_publisher.so">
      <ros>
        <namespace>/test</namespace>
        <remapping>joint_states:=joint_states_test</remapping>
      </ros>
      <update_rate>100</update_rate>
      <joint_name>br_joint</joint_name>
      <joint_name>bl_joint</joint_name>
      <joint_name>fr_joint</joint_name>
      <joint_name>fl_joint</joint_name>
    </plugin>


  </sensor>
</gazebo>




</robot>

sdf文件如下:

<?xml version="1.0" ?>

<sdf version="1.6">

   <model name='lift_robot'>
      <pose>0 0 0 0 0 0</pose>

      <link name="base_footprint"/>
      <link name='base_link'>
        <pose>0 0 0 0 0 0</pose>
        <inertial>
          <mass>1.14395</mass>
          <inertia>
            <ixx>0.126164</ixx>
            <ixy>0</ixy>
            <ixz>0</ixz>
            <iyy>0.416519</iyy>
            <iyz>0</iyz>
            <izz>0.481014</izz>
          </inertia>
        </inertial>
        <visual name='visual'>
          <geometry>
            <box>
              <size>2.4 1.2 2</size>
            </box>
          </geometry>
        </visual>
        <collision name='collision'>
          <geometry>
            <box>
              <size>2.4 1.2 2</size>
            </box>
          </geometry>
        </collision>
      </link>

     <link name='bl_wheel'>
        <pose>-1 -0.6 -1 -1.5707 0 0</pose>
        <inertial>
          <mass>2</mass>
          <inertia>
            <ixx>0.145833</ixx>
            <ixy>0</ixy>
            <ixz>0</ixz>
            <iyy>0.145833</iyy>
            <iyz>0</iyz>
            <izz>0.125</izz>
          </inertia>
        </inertial>
        <visual name='visual'>
          <geometry>
            <sphere>
              <radius>0.35</radius>
            </sphere>
          </geometry>
        </visual>
        <collision name='collision'>
          <geometry>
            <sphere>
              <radius>0.35</radius>
            </sphere>
          </geometry>
          <surface>
            <friction>
              <ode>
                <mu>1</mu>
                <mu2>1</mu2>
                <slip1>0</slip1>
                <slip2>0</slip2>
              </ode>
            </friction>
            <contact>
              <ode>
                <soft_cfm>0</soft_cfm>
                <soft_erp>0.2</soft_erp>
                <kp>1e+13</kp>
                <kd>1</kd>
                <max_vel>0.01</max_vel>
                <min_depth>0.01</min_depth>
              </ode>
            </contact>
          </surface>
        </collision>
      </link>

      <link name='br_wheel'>
        <pose>-1 0.6 -1 -1.5707 0 0</pose>
        <inertial>
          <mass>2</mass>
          <inertia>
            <ixx>0.145833</ixx>
            <ixy>0</ixy>
            <ixz>0</ixz>
            <iyy>0.145833</iyy>
            <iyz>0</iyz>
            <izz>0.125</izz>
          </inertia>
        </inertial>
        <visual name='visual'>
          <geometry>
            <sphere>
              <radius>0.35</radius>
            </sphere>
          </geometry>
        </visual>
        <collision name='collision'>
          <geometry>
            <sphere>
              <radius>0.35</radius>
            </sphere>
          </geometry>
          <surface>
            <friction>
              <ode>
                <mu>1</mu>
                <mu2>1</mu2>
                <slip1>0</slip1>
                <slip2>0</slip2>
              </ode>
            </friction>
            <contact>
              <ode>
                <soft_cfm>0</soft_cfm>
                <soft_erp>0.2</soft_erp>
                <kp>1e+13</kp>
                <kd>1</kd>
                <max_vel>0.01</max_vel>
                <min_depth>0.01</min_depth>
              </ode>
            </contact>
          </surface>
        </collision>
      </link>

      <link name='fl_wheel'>
        <pose>1 -0.6 -1 -1.5707 0 0</pose>
        <inertial>
          <mass>2</mass>
          <inertia>
            <ixx>0.145833</ixx>
            <ixy>0</ixy>
            <ixz>0</ixz>
            <iyy>0.145833</iyy>
            <iyz>0</iyz>
            <izz>0.125</izz>
          </inertia>
        </inertial>
        <visual name='visual'>
          <geometry>
            <sphere>
              <radius>0.35</radius>
            </sphere>
          </geometry>
        </visual>
        <collision name='collision'>
          <geometry>
            <sphere>
              <radius>0.35</radius>
            </sphere>
          </geometry>
          <surface>
            <friction>
              <ode>
                <mu>1</mu>
                <mu2>1</mu2>
                <slip1>0</slip1>
                <slip2>0</slip2>
              </ode>
            </friction>
            <contact>
              <ode>
                <soft_cfm>0</soft_cfm>
                <soft_erp>0.2</soft_erp>
                <kp>1e+13</kp>
                <kd>1</kd>
                <max_vel>0.01</max_vel>
                <min_depth>0.01</min_depth>
              </ode>
            </contact>
          </surface>
        </collision>
      </link>

      <link name='fr_wheel'>
        <pose>1 0.6 -1 -1.5707 0 0</pose>
        <inertial>
          <mass>2</mass>
          <inertia>
            <ixx>0.145833</ixx>
            <ixy>0</ixy>
            <ixz>0</ixz>
            <iyy>0.145833</iyy>
            <iyz>0</iyz>
            <izz>0.125</izz>
          </inertia>
        </inertial>
        <visual name='visual'>
          <geometry>
            <sphere>
              <radius>0.35</radius>
            </sphere>
          </geometry>
        </visual>
        <collision name='collision'>
          <geometry>
            <sphere>
              <radius>0.35</radius>
            </sphere>
          </geometry>
          <surface>
            <friction>
              <ode>
                <mu>1</mu>
                <mu2>1</mu2>
                <slip1>0</slip1>
                <slip2>0</slip2>
              </ode>
            </friction>
            <contact>
              <ode>
                <soft_cfm>0</soft_cfm>
                <soft_erp>0.2</soft_erp>
                <kp>1e+13</kp>
                <kd>1</kd>
                <max_vel>0.01</max_vel>
                <min_depth>0.01</min_depth>
              </ode>
            </contact>
          </surface>
        </collision>
      </link>

      <link name='steering_wheel'>
        <pose>1 0.6 -1 -1.5707 0 0</pose>
        
      </link>

      <joint name="base_joint" type="fixed">
        <parent>base_footprint</parent>
        <child>base_link</child>
      <pose>0.0 0.0 0.00 0 0 0</pose>
      </joint>

      <joint name='fl_wheel_joint' type='universal'>
        <parent>base_link</parent>
        <child>fl_wheel</child>        
      </joint>

      <joint name='fr_wheel_joint' type='universal'>
        <parent>base_link</parent>
        <child>fr_wheel</child>     
      </joint>

      <!--全向轮设置  -->
    <!-- <joint name='bl_wheel_joint' type='ball'>
        <parent>base_link</parent>
        <child>bl_wheel</child>
        
      </joint>

      <joint name='br_wheel_joint' type='ball'>
        <parent>base_link</parent>
        <child>br_wheel</child>
        
    </joint> -->

    <!-- 差速轮设置 -->
    <joint name='bl_wheel_joint' type='revolute'>
        <parent>base_link</parent>
        <child>bl_wheel</child>
        <axis>
          <xyz>0 0 1</xyz>
          <limit>
            <lower>-1.79769e+308</lower>
            <upper>1.79769e+308</upper>
          </limit>
        </axis>
      </joint>

      <joint name='br_wheel_joint' type='revolute'>
        <parent>base_link</parent>
        <child>br_wheel</child>
        <axis>
          <xyz>0 0 1</xyz>
          <limit>
            <lower>-1.79769e+308</lower>
            <upper>1.79769e+308</upper>
          </limit>
        </axis>
      </joint>
      
      <joint name='steering_joint' type='revolute'>
        <parent>base_link</parent>
        <child>steering_wheel</child>
        <axis>
          <xyz>0 0 1</xyz>
          <limit>
            <lower>-1.79769e+308</lower>
            <upper>1.79769e+308</upper>
          </limit>
        </axis>
      </joint>

     <plugin name='diff_drive' filename='libgazebo_ros_diff_drive.so'>
        <ros>
          <argument>cmd_vel:=cmd_vel</argument>
          <argument>odom:=odom</argument>
        </ros>	

        <left_joint>br_wheel_joint</left_joint>
        <right_joint>bl_wheel_joint</right_joint>

        <wheel_separation>1.2</wheel_separation>
        <wheel_diameter>0.7</wheel_diameter>

        <max_wheel_torque>20</max_wheel_torque>
        <max_wheel_acceleration>1.0</max_wheel_acceleration>

        <publish_odom>true</publish_odom>
        <publish_odom_tf>true</publish_odom_tf>
        <publish_wheel_tf>true</publish_wheel_tf>
        
        <odometry_topic>odom</odometry_topic>
        <odometry_frame>odom</odometry_frame>
        <robot_base_frame>base_footprint</robot_base_frame>

      </plugin>

      <!-- <plugin name='planar_move' filename='libgazebo_ros_planar_move.so'>
        <ros>
          <argument>cmd_vel:=cmd_vel</argument>
          <argument>odom:=odom</argument>
        </ros>

        <update_rate>100</update_rate>
        <publish_rate>10</publish_rate>

        <publish_odom>true</publish_odom>
        <publish_odom_tf>true</publish_odom_tf>

        <odometry_frame>odom</odometry_frame>
        <robot_base_frame>base_link</robot_base_frame>

        <covariance_x>0.0001</covariance_x>
        <covariance_y>0.0001</covariance_y>
        <covariance_yaw>0.01</covariance_yaw>
      </plugin> -->


      <!-- <plugin name='ackermann_drive' filename='libgazebo_ros_ackermann_drive.so'>

        <ros>          
          <argument>cmd_vel</argument>
          <argument>odom</argument>
          <argument>distance</argument>
        </ros>

        <update_rate>100.0</update_rate>

     
        <front_left_joint>fl_wheel_joint</front_left_joint>
        <front_right_joint>fr_wheel_joint</front_right_joint>
        <rear_left_joint>bl_wheel_joint</rear_left_joint>
        <rear_right_joint>br_wheel_joint</rear_right_joint>
        <left_steering_joint>fl_wheel_joint</left_steering_joint>
        <right_steering_joint>fr_wheel_joint</right_steering_joint>
        <steering_wheel_joint>steering_joint</steering_wheel_joint>

        <max_steer>0.6458</max_steer>

        <max_steering_angle>7.85</max_steering_angle>

        <max_speed>20</max_speed>

        <left_steering_pid_gain>1500 0 1</left_steering_pid_gain>
        <left_steering_i_range>0 0</left_steering_i_range>
        <right_steering_pid_gain>1500 0 1</right_steering_pid_gain>
        <right_steering_i_range>0 0</right_steering_i_range>
        <linear_velocity_pid_gain>1000 0 1</linear_velocity_pid_gain>
        <linear_velocity_i_range>0 0</linear_velocity_i_range>

        <publish_odom>true</publish_odom>
        <publish_odom_tf>true</publish_odom_tf>
        <publish_wheel_tf>true</publish_wheel_tf>
        <publish_distance>true</publish_distance>

        <odometry_frame>odom</odometry_frame>
        <robot_base_frame>base_footprint</robot_base_frame>

      </plugin> -->


         <!--发布其它关节的位置信息-->
      <plugin name="gazebo_ros_joint_state_publisher"
          filename="libgazebo_ros_joint_state_publisher.so">
          <ros>
           <argument>joint_states:=joint_states</argument>
          </ros>

          <update_rate>30</update_rate>
          <joint_name>br_wheel_joint</joint_name>
          <joint_name>bl_wheel_joint</joint_name>
      </plugin>
     
      <link name="ray_link">
        <pose>0 0 1.2 0 0 0</pose>
        <visual name="visual_box">
          <geometry>
            <box>
              <size>0.2 0.2 0.2</size>
            </box>
          </geometry>
        </visual>
        <collision name="collision_box">
          <geometry>
            <box>
              <size>0.2 0.2 0.2</size>
            </box>
          </geometry>
          <laser_retro>100.0</laser_retro>
        </collision>
         
      <!-- ray sensor -->
        <sensor name="sensor_ray" type="ray">
          <always_on>true</always_on>
          <visualize>true</visualize>         
          <update_rate>20</update_rate>
          <ray>
            <scan>
              <horizontal>
                <samples>720</samples>
                <resolution>0.5</resolution>
                <min_angle>-3.1415</min_angle>
                <max_angle>3.1415</max_angle>
              </horizontal>
              <!-- <vertical>
                <samples>100</samples>
                <resolution>1.0</resolution>
                <min_angle>-0.5236</min_angle>
                <max_angle>0.5236</max_angle>
              </vertical> -->
            </scan>
            <range>
              <min>0.2</min>
              <max>50.0</max>	           
            </range>
	          <noise>
              <type>gaussian</type>
              <mean>0.0</mean>
              <stddev>0.01</stddev>
            </noise>
          </ray>    
          <plugin name="laserscan" filename="libgazebo_ros_ray_sensor.so">
            <ros>
              <!-- <namespace>/ray</namespace> -->
              <argument>~/out:=scan</argument>
            </ros>
            <output_type>sensor_msgs/LaserScan</output_type>
          </plugin>

        </sensor>
    </link>


    <joint name='laser_joint' type='fixed'>
        <parent>base_link</parent>
        <child>ray_link</child>    
    </joint>

    <link name="imu_link">
      <sensor name="imu" type="imu">
        <always_on>true</always_on>
        <update_rate>100</update_rate>
         <imu>
          <angular_velocity>
            <x>
              <noise type="gaussian">
                <mean>0.0</mean>
                <stddev>2e-4</stddev>
              </noise>
            </x>
            <y>
              <noise type="gaussian">
                <mean>0.0</mean>
                <stddev>2e-4</stddev>
              </noise>
            </y>
            <z>
              <noise type="gaussian">
                <mean>0.0</mean>
                <stddev>2e-4</stddev>
              </noise>
            </z>
          </angular_velocity>
          <linear_acceleration>
            <x>
              <noise type="gaussian">
                <mean>0.0</mean>
                <stddev>1.7e-2</stddev>
              </noise>
            </x>
            <y>
              <noise type="gaussian">
                <mean>0.0</mean>
                <stddev>1.7e-2</stddev>
              </noise>
            </y>
            <z>
              <noise type="gaussian">
                <mean>0.0</mean>
                <stddev>1.7e-2</stddev>
              </noise>
            </z>
          </linear_acceleration>
        </imu>
        <plugin name="imu" filename="libgazebo_ros_imu_sensor.so">
          <ros>
            <argument>~/out:=imu</argument>
          </ros>
        </plugin>
      </sensor>
    </link>

    <joint name="imu_joint" type="fixed">
      <parent>base_link</parent>
      <child>imu_link</child>
      <pose>0.0 0 0.0 0 0 0</pose>
      <axis>
        <xyz>0 0 1</xyz>
      </axis>
    </joint>

    <link name="gps_link">
      <pose>0 0 10 0 0 0</pose>
      <sensor name="my_gps" type="gps">
          <always_on>true</always_on>
          <update_rate>30</update_rate>
          <gps>
            <position_sensing>
              <horizontal>
                <noise type="gaussian">
                  <mean>0.0</mean>
                  <stddev>2e-4</stddev>
                </noise>
              </horizontal>
              <vertical>
                <noise type="gaussian">
                  <mean>0.0</mean>
                  <stddev>2e-4</stddev>
                </noise>
              </vertical>
            </position_sensing>
          </gps>
          <plugin name="gps_plugin" filename="libgazebo_ros_gps_sensor.so">
            <ros>
              <argument>~/out:=gps_data</argument>
            </ros>
          </plugin>
        </sensor>
    </link>
    
    
    <joint name="gps_joint" type="fixed">
      <parent>base_link</parent>
      <child>gps_link</child>
    </joint>

     

    </model>
 
</sdf>