ros2+Gazebo的一个简单入门例子

1、Gazebo简介

Gazebo是ROS系统中最为常用的三维物理仿真平台，支持动力学引擎，可以实现高质量的图形渲染，不仅可以模拟机器人及周边环境，还可以加入摩擦力、弹性系数等物理属性。所以类似Gazebo这样的仿真平台，可以帮助我们验证机器人算法、优化机器人设计、测试机器人场景应用，为机器人开发提供更多可能。

2、安装运行

# 1通过命令apt进行安装gazebo
sudo apt install gazebo

# 2下载model库
mkdir -p ~/.gazebo
cd ~/.gazebo
# Clone to a temporary location
git clone https://gitee.com/ohhuo/gazebo_models.git /tmp/gazebo_models

# Copy contents, overwriting existing files
cp -rf /tmp/gazebo_models/* ~/.gazebo/models/

# Remove the temporary clone
rm -rf /tmp/gazebo_models
rm -rf ~/.gazebo/models/.git

#3 过以下命令启动或直接通过桌面图标启动

gazebo --verbose -s libgazebo_ros_init.so -s libgazebo_ros_factory.so

 

3、安装gazebo节点与启动服务

#0、安装节点包
sudo apt install ros-${ROS_DISTRO}-gazebo-*
#或
sudo apt install ros-$ROS_DISTRO-gazebo-ros-pkgs

#1、查看节点

ros2 node list
#2、查看节点的对外提供的服务

ros2 service list
# 借助AI工具，掌握服务用途。例如：
#/spawn_entity，用于加载模型到gazebo中
#/get_model_list，用于获取模型列表
#/delete_entity，用于删除gazbeo中已经加载的模型

 

4、创建功能包，建urdf格式仿真模型

具体是：

#创建一个myrobot功能包，用来存放我们的URDF模型文件和启动文件

$ mkdir -p ws/src

$ cd ws/src

$ ros2 pkg create myrobot --build-type ament_cmake

#进入到myrobot的目录下，创建launch、urdf文件夹，在urdf文件夹下创建一个demo01_base.urdf文件，这个文件就是一个简单的演示文件，只有一个基础的立方体。

 

<robot name="myrobot">

    <link name="base_link">

        <visual>

            <geometry>

                <box size="0.2 0.2 0.2"/>

            </geometry>

            <origin xyz="0.0 0.0 0.0"/>

        </visual>

        <collision>

            <geometry>

                <box size="0.2 0.2 0.2"/>

            </geometry>

            <origin xyz="0.0 0.0 0.0"/>

        </collision>

        <inertial>

            <mass value="0.1"/>

            <inertia ixx="0.000190416666667" ixy="0" ixz="0" iyy="0.0001904" iyz="0" izz="0.00036"/>

        </inertial>

    </link>

    <gazebo reference="base_link">

        <material>Gazebo/Red</material>

    </gazebo>

</robot>

 

 

5、编写launch文件，启动仿真，在gazebo显示

launch文件的编写，launch文件主要启动两个部分，启动Gazebo文件，然后将机器人模型加载到Gazebo中。 文件树如下图

在launch目录下新建一个bringup_model.launch.py文件完整的启动文件如下：

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 = 'myrobot'
    package_name = 'myrobot'
    urdf_name = "demo01_base.urdf"
    
    ld = LaunchDescription()
    pkg_share = FindPackageShare(package=package_name).find(package_name)
    urdf_model_path = os.path.join(pkg_share, f'urdf/{urdf_name}')
    
    # 检查文件是否存在
    if not os.path.exists(urdf_model_path):
        print(f"Warning: URDF file not found at {urdf_model_path}")
    
    # Start Gazebo (使用 gazebo_ros 的 launch 文件更可靠)
    # 对应的bash命令行：$ gazebo --verbose -s libgazebo_ros_init.so -s libgazebo_ros_factory.so
    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

在Cmakelist中填入以下内容，用于将我们的urdf和launch文件夹安装进install目录下

cmake_minimum_required(VERSION 3.8)
project(myrobot)

if(CMAKE_COMPILER_IS_GNUCXX OR CMAKE_CXX_COMPILER_ID MATCHES "Clang")
  add_compile_options(-Wall -Wextra -Wpedantic)
endif()

# find dependencies
find_package(ament_cmake REQUIRED)
# uncomment the following section in order to fill in
# further dependencies manually.
# find_package(<dependency> REQUIRED)

if(BUILD_TESTING)
  find_package(ament_lint_auto REQUIRED)
  # the following line skips the linter which checks for copyrights
  # comment the line when a copyright and license is added to all source files
  set(ament_cmake_copyright_FOUND TRUE)
  # the following line skips cpplint (only works in a git repo)
  # comment the line when this package is in a git repo and when
  # a copyright and license is added to all source files
  set(ament_cmake_cpplint_FOUND TRUE)
  ament_lint_auto_find_test_dependencies()
endif()
# 将我们的urdf和launch文件夹安装进install目录下
install(

    DIRECTORY urdf launch

    DESTINATION share/${PROJECT_NAME}

)

ament_package()

 在workspace目录下，编译此包,启动*.launch.py文件：

colcon build --packages-select myrobot

. install/setup.bash

ros2 launch myrobot bringup_model.launch.py

gazebo显示长方体