第九章机器人仿真入门第三节《将启动gazebo和生产fishbot写成launch文件》编写了gazebo.launch.py之后，运行gazebo没有显示机器人，也没有出现报错

er

请问一下各位大佬这是什么原因？

头怎么还不秃啊

同问，请问兄弟你解决了吗？

小鱼

@441755535 把这个launch拆成两个，先启动gazebo，再启动机器人

import os
from launch import LaunchDescription
from launch.actions import ExecuteProcess
from launch_ros.actions import Node
from launch_ros.substitutions import FindPackageShare


def generate_launch_description():
    robot_name_in_model = 'fishbot'
    package_name = 'fishbot_description'
    urdf_name = "fishbot_gazebo.urdf"

    ld = LaunchDescription()
    pkg_share = FindPackageShare(package=package_name).find(package_name) 
    urdf_model_path = os.path.join(pkg_share, f'urdf/{urdf_name}')

    # Start Gazebo server
    start_gazebo_cmd =  ExecuteProcess(
        cmd=['gazebo', '--verbose','-s', 'libgazebo_ros_init.so', '-s', 'libgazebo_ros_factory.so'],
        output='screen')

    # Launch the robot
    spawn_entity_cmd = Node(
        package='gazebo_ros', 
        executable='spawn_entity.py',
        arguments=['-entity', robot_name_in_model,  '-file', urdf_model_path ], output='screen')

    ld.add_action(start_gazebo_cmd)
   # ld.add_action(spawn_entity_cmd)


    return ld

import os
from launch import LaunchDescription
from launch.actions import ExecuteProcess
from launch_ros.actions import Node
from launch_ros.substitutions import FindPackageShare


def generate_launch_description():
    robot_name_in_model = 'fishbot'
    package_name = 'fishbot_description'
    urdf_name = "fishbot_gazebo.urdf"

    ld = LaunchDescription()
    pkg_share = FindPackageShare(package=package_name).find(package_name) 
    urdf_model_path = os.path.join(pkg_share, f'urdf/{urdf_name}')

    # Start Gazebo server
    start_gazebo_cmd =  ExecuteProcess(
        cmd=['gazebo', '--verbose','-s', 'libgazebo_ros_init.so', '-s', 'libgazebo_ros_factory.so'],
        output='screen')

    # Launch the robot
    spawn_entity_cmd = Node(
        package='gazebo_ros', 
        executable='spawn_entity.py',
        arguments=['-entity', robot_name_in_model,  '-file', urdf_model_path ], output='screen')

   # ld.add_action(start_gazebo_cmd)
   ld.add_action(spawn_entity_cmd)


    return ld

头怎么还不秃啊

中间会报这些错误，然后在gazebo里就没有显示模型，launch拆成两个或者合成一个都是一样。
ModuleNotFoundError: No module named 'rclpy._rclpy_pybind11'
[spawn_entity.py-2] The C extension '/opt/ros/humble/lib/python3.10/site-packages/_rclpy_pybind11.cpython-38-x86_64-linux-gnu.so' isn't present on the system. Please refer to 'https://docs.ros.org/en/humble/Guides/Installation-Troubleshooting.html#import-failing-without-library-present-on-the-system' for possible solutions
[ERROR] [spawn_entity.py-2]: process has died [pid 11696, exit code 1, cmd '/opt/ros/humble/lib/gazebo_ros/spawn_entity.py -entity fishbot -file /home/hdm/d2lros2/chapt8_ws/install/fishbot_description/share/fishbot_description/urdf/fishbot_gazebo.urdf --ros-args'].

头怎么还不秃啊

求助求助！！！！

小鱼

@441755535 在第九章机器人仿真入门第三节《将启动gazebo和生产fishbot写成launch文件》编写了gazebo.launch.py之后，运行gazebo没有显示机器人，也没有出现报错中说：

ModuleNotFoundError: No module named 'rclpy._rclpy_pybind11'

conda 退掉

头怎么还不秃啊

此回复已被删除！

头怎么还不秃啊

此回复已被删除！

头怎么还不秃啊

@小鱼退掉conda后gazebo可以加载模型了，但是会报下面的错误
[gazebo-1] [Err] [Plugin.hh:212] Failed to load plugin libgazebo_ros_imu_sensor.so: libgazebo_ros_imu_sensor.so: cannot open shared object file: No such file or directory
[gazebo-1] [Err] [Plugin.hh:212] Failed to load plugin libgazebo_ros_ray_sensor.so: libgazebo_ros_ray_sensor.so: cannot open shared object file: No such file or directory
[gazebo-1] [Err] [Plugin.hh:212] Failed to load plugin libgazebo_ros_diff_drive.so: libgazebo_ros_diff_drive.so: cannot open shared object file: No such file or directory
[spawn_entity.py-2] [INFO] [1681979467.799171068] [spawn_entity]: Spawn status: SpawnEntity: Successfully spawned entity [fishbot]
[gazebo-1] [Err] [Plugin.hh:212] Failed to load plugin libgazebo_ros_joint_state_publisher.so: libgazebo_ros_joint_state_publisher.so: cannot open shared object file: No such file or directory
[INFO] [spawn_entity.py-2]: process has finished cleanly [pid 37915]
[gazebo-1] context mismatch in svga_surface_destroy
[gazebo-1] context mismatch in svga_surface_destroy

头怎么还不秃啊

@441755535
urdf代码如下
<?xml version="1.0"?>
<robot name="fishbot">

<link name="base_footprint"/>

<link name="base_link">
<visual>
<origin xyz="0 0 0.0" rpy="0 0 0"/>
<geometry>
<cylinder length="0.12" radius="0.10"/>
</geometry>
<material name="blue">
<color rgba="0.1 0.1 1.0 0.5" />
</material>
</visual>
<collision>
<origin xyz="0 0 0.0" rpy="0 0 0"/>
<geometry>
<cylinder length="0.12" radius="0.10"/>
</geometry>
<material name="blue">
<color rgba="0.1 0.1 1.0 0.5" />
</material>
</collision>
<inertial>
<mass value="0.2"/>
<inertia ixx="0.0122666" ixy="0" ixz="0" iyy="0.0122666" iyz="0" izz="0.02"/>
</inertial>
</link>

<link name="laser_link">
<visual>
<origin xyz="0 0 0" rpy="0 0 0"/>
<geometry>
<cylinder length="0.02" radius="0.02"/>
</geometry>
<material name="black">
<color rgba="0.0 0.0 0.0 0.5" />
</material>
</visual>
<collision>
<origin xyz="0 0 0" rpy="0 0 0"/>
<geometry>
<cylinder length="0.02" radius="0.02"/>
</geometry>
<material name="black">
<color rgba="0.0 0.0 0.0 0.5" />
</material>
</collision>
<inertial>
<mass value="0.1"/>
<inertia ixx="0.000190416666667" ixy="0" ixz="0" iyy="0.0001904" iyz="0" izz="0.00036"/>
</inertial>
</link>

<joint name="laser_joint" type="fixed">
<parent link="base_link" />
<child link="laser_link" />
<origin xyz="0 0 0.075" />
</joint>

<joint name="imu_joint" type="fixed">
<parent link="base_link" />
<child link="imu_link" />
<origin xyz="0 0 0.02" />
</joint>

<gazebo reference="caster_link">
<material>Gazebo/Black</material>
</gazebo>

<gazebo>
<plugin name='diff_drive' filename='libgazebo_ros_diff_drive.so'>
<ros>
<namespace>/</namespace>
<remapping>cmd_vel:=cmd_vel</remapping>
<remapping>odom:=odom</remapping>
</ros>
<update_rate>30</update_rate>



<left_joint>left_wheel_joint</left_joint>
<right_joint>right_wheel_joint</right_joint>

<wheel_separation>0.2</wheel_separation>
<wheel_diameter>0.065</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>false</publish_wheel_tf>
<odometry_frame>odom</odometry_frame>
<robot_base_frame>base_footprint</robot_base_frame>
</plugin>

  <plugin name="fishbot_joint_state" filename="libgazebo_ros_joint_state_publisher.so">
    <ros>
      <remapping>~/out:=joint_states</remapping>
    </ros>
    <update_rate>30</update_rate>
    <joint_name>right_wheel_joint</joint_name>
    <joint_name>left_wheel_joint</joint_name>
  </plugin>    
  </gazebo> 

  <gazebo reference="laser_link">
    <material>Gazebo/Black</material>
  </gazebo>

<gazebo reference="imu_link">
  <sensor name="imu_sensor" type="imu">
  <plugin filename="libgazebo_ros_imu_sensor.so" name="imu_plugin">
      <ros>
        <namespace>/</namespace>
        <remapping>~/out:=imu</remapping>
      </ros>
      <initial_orientation_as_reference>false</initial_orientation_as_reference>
    </plugin>
    <always_on>true</always_on>
    <update_rate>100</update_rate>
    <visualize>true</visualize>
    <imu>
      <angular_velocity>
        <x>
          <noise type="gaussian">
            <mean>0.0</mean>
            <stddev>2e-4</stddev>
            <bias_mean>0.0000075</bias_mean>
            <bias_stddev>0.0000008</bias_stddev>
          </noise>
        </x>
        <y>
          <noise type="gaussian">
            <mean>0.0</mean>
            <stddev>2e-4</stddev>
            <bias_mean>0.0000075</bias_mean>
            <bias_stddev>0.0000008</bias_stddev>
          </noise>
        </y>
        <z>
          <noise type="gaussian">
            <mean>0.0</mean>
            <stddev>2e-4</stddev>
            <bias_mean>0.0000075</bias_mean>
            <bias_stddev>0.0000008</bias_stddev>
          </noise>
        </z>
      </angular_velocity>
      <linear_acceleration>
        <x>
          <noise type="gaussian">
            <mean>0.0</mean>
            <stddev>1.7e-2</stddev>
            <bias_mean>0.1</bias_mean>
            <bias_stddev>0.001</bias_stddev>
          </noise>
        </x>
        <y>
          <noise type="gaussian">
            <mean>0.0</mean>
            <stddev>1.7e-2</stddev>
            <bias_mean>0.1</bias_mean>
            <bias_stddev>0.001</bias_stddev>
          </noise>
        </y>
        <z>
          <noise type="gaussian">
            <mean>0.0</mean>
            <stddev>1.7e-2</stddev>
            <bias_mean>0.1</bias_mean>
            <bias_stddev>0.001</bias_stddev>
          </noise>
        </z>
      </linear_acceleration>
    </imu>
  </sensor>
</gazebo>

<gazebo reference="laser_link">
  <sensor name="laser_sensor" type="ray">
  <always_on>true</always_on>
  <visualize>true</visualize>
  <update_rate>5</update_rate>
  <pose>0 0 0.075 0 0 0</pose>
  <ray>
      <scan>
        <horizontal>
          <samples>360</samples>
          <resolution>1.000000</resolution>
          <min_angle>0.000000</min_angle>
          <max_angle>6.280000</max_angle>
        </horizontal>
      </scan>
      <range>
        <min>0.120000</min>
        <max>3.5</max>
        <resolution>0.015000</resolution>
      </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>/tb3</namespace> -->
      <remapping>~/out:=scan</remapping>
    </ros>
    <output_type>sensor_msgs/LaserScan</output_type>
    <frame_name>laser_link</frame_name>
  </plugin>
  </sensor>
</gazebo>

</robot>

丘洪键

解决：把launch中的urdf_name = "fishbot_gazebo.urdf" 改为：urdf_name = "fishbot_base.urdf"

原因：（自己摸索的，不知道对不对，我自己按上面改了之后就能显示了）
应该是urdf的文件名搞错了，第8章跟着教程建立urdf的文件名是_base结尾的，如下图：

然后现在的launch文件里是_gazebo结尾的：

运行就加载不了urdf文件了，报错：

看看这个路径下的urdf文件，并没有fishbot_gazebo.urdf

丘洪键

@1094967296 首先确保用rqt显示是没问题的，确保urdf里的内容是对的

18730832756

此回复已被删除！

18730832756

@1094967296 牛皮，哥，我找了半天的错没想到是名错了

第九章机器人仿真入门第三节《 将启动gazebo和生产fishbot写成launch文件》编写了gazebo.launch.py之后，运行gazebo没有显示机器人，也没有出现报错

第九章机器人仿真入门第三节《将启动gazebo和生产fishbot写成launch文件》编写了gazebo.launch.py之后，运行gazebo没有显示机器人，也没有出现报错