手把手开始ROS仿真小车（一）仿真环境及小车搭建
最近打算自己完成一个无人驾驶汽车仿真运行的项目，因此记录一下过程，希望能帮助到需要搭建ROS仿真环境的人，主要参考了冰达机器人的课程，在B站上也有相关视频可以学习
实现过程
1.创建工作区
2.gazebo 绘制地图，并保存为 .world 文件
3.urdf 小车模型和 xacro 小车模型
4.ros 运行地图和小车模型
5.查看传感器数据
一、创建工作区
mkdir -p ~/catkin_ws/src/tutorials // 创建文件夹
cd ~/catkin_ws/src/tutorials
mkdir launch // 存放 launch 文件
mkdir urdf // 存放小车模型文件
mkdir world // 存放地图文件
一个简单的工作区就创建好了，后续再一步步往里面添加文件
二、gazebo绘制地图
1.打开gazebo
sudo gazebo // 打开gazebo，后续保存文件可能需要管理员权限
2.进入编辑界面
3.点击 wall 后可绘制墙壁
4.点击 Add Texture 可修改墙壁纹理
5.点击 file 的 save as 保存模型文件
6.选择保存名称和保存位置
7.点击模型，通过 pose 修改模型位置
8.通过 insert 可添加其他模型
9.地图绘制好后，保存为 .world 地图文件（文件后缀名一定要是 .world）
10.将 .world 文件复制到 ~/catkin_ws/src/world 文件夹内，地图环境就搭建好了
三、小车模型
小车模型通常有两种，一种是 urdf，一种是 sacro，两种都有差不多，定义也是有固定模板，因此这里直接放两种模型的代码
1.urdf 小车模型文件1：myrot.urdf，具体内容如下：
<?xml version="1.0"?>
<robot name="mybot">
<link name="base_footprint"/>
<joint name="base_joint" type="fixed">
<parent link="base_footprint"/>
<child link="base_link"/>
<origin rpy="0 0 0" xyz="0 0 0"/>
</joint>
<link name="base_link">
<inertial>
<origin xyz="0 0 0" rpy="0 0 0"/>
<mass value="0.1"/>
<inertia ixx="0.0001" ixy="0" ixz="0" iyy="0.0001" iyz="0" izz="0.001" />
</inertial>
<visual>
<geometry>
<box size="0.25 0.16 0.05"/>
</geometry>
<origin rpy="0 0 0" xyz="0 0 0"/>
<material name="blue">
<color rgba="0 0 0.8 1"/>
</material>
</visual>
<collision>
<origin xyz="0 0 0" rpy="0 0 0"/>
<geometry>
<box size="0.25 0.16 0.05"/>
</geometry>
</collision>
</link>
<link name="right_wheel_link">
<inertial>
<origin xyz="0 0 0" rpy="0 0 0"/>
<mass value="0.1"/>
<inertia ixx="0.0001" ixy="0" ixz="0" iyy="0.0001" iyz="0" izz="0.0001" />
</inertial>
<visual>
<geometry>
<cylinder length="0.02" radius="0.025"/>
</geometry>
<material name="black">
<color rgba="0 0 0 1"/>
</material>
</visual>
<collision>
<origin xyz="0 0 0" rpy="0 0 0"/>
<geometry>
<cylinder length="0.02" radius="0.025"/>
</geometry>
</collision>
</link>
<joint name="right_wheel_joint" type="continuous">
<axis xyz="0 0 -1"/>
<parent link="base_link"/>
<child link="right_wheel_link"/>
<origin rpy="1.5707 0 0" xyz=" 0.1 -0.09 -0.03"/>
</joint>
<link name="left_wheel_link">
<inertial>
<origin xyz="0 0 0" rpy="0 0 0"/>
<mass value="0.1"/>
<inertia ixx="0.0001" ixy="0" ixz="0" iyy="0.0001" iyz="0" izz="0.0001" />
</inertial>
<visual>
<geometry>
<cylinder length="0.02" radius="0.025"/>
</geometry>
<material name="black">
<color rgba="0 0 0 1"/>
</material>
</visual>
<collision>
<origin xyz="0 0 0" rpy="0 0 0"/>
<geometry>
<cylinder length="0.02" radius="0.025"/>
</geometry>
</collision>
</link>
<joint name="left_wheel_joint" type="continuous">
<axis xyz="0 0 -1"/>
<parent link="base_link"/>
<child link="left_wheel_link"/>
<origin rpy="1.5707 0 0" xyz="0.1 0.09 -0.03"/>
</joint>
<link name="ball_wheel_link">
<inertial>
<origin xyz="0 0 0" rpy="0 0 0"/>
<mass value="0.1"/>
<inertia ixx="0" ixy="0" ixz="0" iyy="0" iyz="0" izz="0" />
</inertial>
<visual>
<geometry>
<sphere radius="0.025"/>
</geometry>
<material name="black">
<color rgba="0 0 0 1"/>
</material>
</visual>
<collision>
<origin xyz="0 0 0" rpy="0 0 0"/>
<geometry>
<sphere radius="0.025"/>
</geometry>
</collision>
</link>
<joint name="ball_wheel_joint" type="fixed">
<axis xyz="0 0 1"/>
<parent link="base_link"/>
<child link="ball_wheel_link"/>
<origin rpy="0 0 0" xyz="-0.10 0 -0.03"/>
</joint>
</robot>
上述小车模型文件没有传感器配置！
2.xacro小车模型文件分为两部分，分别为 myrot.xacro 和 myrot.gazebo.xacro ，具体内容如下：
myrot.xacro：
<?xml version="1.0"?>
<robot name="mybot" xmlns:xacro="http://ros.org/wiki/xacro">
<xacro:include filename="$(find tutorials)/urdf/mybot.gazebo.xacro" />
<link name="base_footprint"/>
<joint name="base_joint" type="fixed">
<parent link="base_footprint"/>
<child link="base_link"/>
<origin rpy="0 0 0" xyz="0 0 0"/>
</joint>
<link name="base_link">
<inertial>
<origin xyz="0 0 0" rpy="0 0 0"/>
<mass value="0.1"/>
<inertia ixx="0.0001" ixy="0" ixz="0" iyy="0.0001" iyz="0" izz="0.001" />
</inertial>
<visual>
<geometry>
<box size="0.25 0.16 0.05"/>
</geometry>
<origin rpy="0 0 0" xyz="0 0 0"/>
<material name="blue">
<color rgba="0 0 0.8 1"/>
</material>
</visual>
<collision>
<origin xyz="0 0 0" rpy="0 0 0"/>
<geometry>
<box size="0.25 0.16 0.05"/>
</geometry>
</collision>
</link>
<link name="right_wheel_link">
<inertial>
<origin xyz="0 0 0" rpy="0 0 0"/>
<mass value="0.1"/>
<inertia ixx="0.0001" ixy="0" ixz="0" iyy="0.0001" iyz="0" izz="0.0001" />
</inertial>
<visual>
<geometry>
<cylinder length="0.02" radius="0.025"/>
</geometry>
<material name="black">
<color rgba="0 0 0 1"/>
</material>
</visual>
<collision>
<origin xyz="0 0 0" rpy="0 0 0"/>
<geometry>
<cylinder length="0.02" radius="0.025"/>
</geometry>
</collision>
</link>
<joint name="right_wheel_joint" type="continuous">
<axis xyz="0 0 -1"/>
<parent link="base_link"/>
<child link="right_wheel_link"/>
<origin rpy="1.5707 0 0" xyz=" 0.1 -0.09 -0.03"/>
</joint>
<link name="left_wheel_link">
<inertial>
<origin xyz="0 0 0" rpy="0 0 0"/>
<mass value="0.1"/>
<inertia ixx="0.0001" ixy="0" ixz="0" iyy="0.0001" iyz="0" izz="0.0001" />
</inertial>
<visual>
<geometry>
<cylinder length="0.02" radius="0.025"/>
</geometry>
<material name="black">
<color rgba="0 0 0 1"/>
</material>
</visual>
<collision>
<origin xyz="0 0 0" rpy="0 0 0"/>
<geometry>
<cylinder length="0.02" radius="0.025"/>
</geometry>
</collision>
</link>
<joint name="left_wheel_joint" type="continuous">
<axis xyz="0 0 -1"/>
<parent link="base_link"/>
<child link="left_wheel_link"/>
<origin rpy="1.5707 0 0" xyz="0.1 0.09 -0.03"/>
</joint>
<link name="ball_wheel_link">
<inertial>
<origin xyz="0 0 0" rpy="0 0 0"/>
<mass value="0.1"/>
<inertia ixx="0" ixy="0" ixz="0" iyy="0" iyz="0" izz="0" />
</inertial>
<visual>
<geometry>
<sphere radius="0.025"/>
</geometry>
<material name="black">
<color rgba="0 0 0 1"/>
</material>
</visual>
<collision>
<origin xyz="0 0 0" rpy="0 0 0"/>
<geometry>
<sphere radius="0.025"/>
</geometry>
</collision>
</link>
<joint name="ball_wheel_joint" type="fixed">
<axis xyz="0 0 1"/>
<parent link="base_link"/>
<child link="ball_wheel_link"/>
<origin rpy="0 0 0" xyz="-0.10 0 -0.03"/>
</joint>
<!-- imu sensor -->
<link name="imu">
<visual>
<geometry>
<box size="0.01 0.01 0.01"/>
</geometry>
<material name="white">
<color rgba="1 1 1 1"/>
</material>
</visual>
</link>
<joint name="imu_joint" type="fixed">
<parent link="base_link"/>
<child link="imu"/>
<origin xyz="0.08 0 0.025"/>
</joint>
<!-- camera -->
<link name="base_camera_link">
<visual>
<geometry>
<box size="0.02 0.03 0.03"/>
</geometry>
<material name="white">
<color rgba="1 1 1 1"/>
</material>
</visual>
</link>
<joint name="camera_joint" type="fixed">
<parent link="base_link"/>
<child link="base_camera_link"/>
<origin xyz="0.1 0 0.025"/>
</joint>
<!-- laser lidar -->
<link name="base_laser_link">
<visual>
<geometry>
<cylinder length="0.06" radius="0.04"/>
</geometry>
<material name="white">
<color rgba="1 1 1 1"/>
</material>
</visual>
</link>
<joint name="laser_joint" type="fixed">
<parent link="base_link"/>
<child link="base_laser_link"/>
<origin xyz="0 0.0 0.06"/>
</joint>
</robot>
myrot.gazebo.xacro：
<?xml version="1.0"?>
<robot name="mybot" xmlns:xacro="http://ros.org/wiki/xacro">
<xacro:arg name="laser_visual" default="false"/>
<xacro:arg name="camera_visual" default="false"/>
<xacro:arg name="imu_visual" default="false"/>
<gazebo reference="base_link">
<material>Gazebo/DarkGrey</material>
</gazebo>
<gazebo reference="left_wheel_link">
<mu1>0.5</mu1>
<mu2>0.5</mu2>
<kp>500000.0</kp>
<kd>10.0</kd>
<minDepth>0.001</minDepth>
<maxVel>1.0</maxVel>
<fdir1>1 0 0</fdir1>
<material>Gazebo/DarkGrey</material>
</gazebo>
<gazebo reference="right_wheel_link">
<mu1>0.5</mu1>
<mu2>0.5</mu2>
<kp>500000.0</kp>
<kd>10.0</kd>
<minDepth>0.001</minDepth>
<maxVel>1.0</maxVel>
<fdir1>1 0 0</fdir1>
<material>Gazebo/FlatBlack</material>
</gazebo>
<gazebo reference="ball_wheel_link">
<mu1>0.1</mu1>
<mu2>0.1</mu2>
<kp>500000.0</kp>
<kd>100.0</kd>
<minDepth>0.001</minDepth>
<maxVel>1.0</maxVel>
<material>Gazebo/FlatBlack</material>
</gazebo>
<gazebo reference="imu">
<sensor type="imu" name="imu">
<always_on>true</always_on>
<visualize>$(arg imu_visual)</visualize>
</sensor>
<material>Gazebo/FlatBlack</material>
</gazebo>
<gazebo>
<plugin name="mybot_controller" filename="libgazebo_ros_diff_drive.so">
<commandTopic>cmd_vel</commandTopic>
<odometryTopic>odom</odometryTopic>
<odometryFrame>odom</odometryFrame>
<odometrySource>world</odometrySource>
<publishOdomTF>true</publishOdomTF>
<robotBaseFrame>base_footprint</robotBaseFrame>
<publishWheelTF>false</publishWheelTF>
<publishTf>true</publishTf>
<publishWheelJointState>true</publishWheelJointState>
<legacyMode>false</legacyMode>
<updateRate>30</updateRate>
<leftJoint>left_wheel_joint</leftJoint>
<rightJoint>right_wheel_joint</rightJoint>
<wheelSeparation>0.180</wheelSeparation>
<wheelDiameter>0.05</wheelDiameter>
<wheelAcceleration>10</wheelAcceleration>
<wheelTorque>100</wheelTorque>
<rosDebugLevel>na</rosDebugLevel>
</plugin>
</gazebo>
<gazebo>
<plugin name="imu_plugin" filename="libgazebo_ros_imu.so">
<alwaysOn>true</alwaysOn>
<bodyName>imu</bodyName>
<frameName>imu</frameName>
<topicName>imu</topicName>
<serviceName>imu_service</serviceName>
<gaussianNoise>0.0</gaussianNoise>
<updateRate>0</updateRate>
<imu>
<noise>
<type>gaussian</type>
<rate>
<mean>0.0</mean>
<stddev>2e-4</stddev>
<bias_mean>0.0000075</bias_mean>
<bias_stddev>0.0000008</bias_stddev>
</rate>
<accel>
<mean>0.0</mean>
<stddev>1.7e-2</stddev>
<bias_mean>0.1</bias_mean>
<bias_stddev>0.001</bias_stddev>
</accel>
</noise>
</imu>
</plugin>
</gazebo>
<gazebo reference="base_laser_link">
<material>Gazebo/FlatBlack</material>
<sensor type="ray" name="rplidar_sensor">
<pose>0 0 0 0 0 0</pose>
<visualize>$(arg laser_visual)</visualize>
<update_rate>7</update_rate>
<ray>
<scan>
<horizontal>
<samples>720</samples>
<resolution>0.5</resolution>
<min_angle>0.0</min_angle>
<max_angle>6.28319</max_angle>
</horizontal>
</scan>
<range>
<min>0.120</min>
<max>12.0</max>
<resolution>0.015</resolution>
</range>
<noise>
<type>gaussian</type>
<mean>0.0</mean>
<stddev>0.01</stddev>
</noise>
</ray>
<plugin name="gazebo_ros_rplidar_controller" filename="libgazebo_ros_laser.so">
<topicName>scan</topicName>
<frameName>base_laser_link</frameName>
</plugin>
</sensor>
</gazebo>
<gazebo reference="base_camera_link">
<sensor type="camera" name="csi Camera">
<always_on>true</always_on>
<visualize>$(arg camera_visual)</visualize>
<camera>
<horizontal_fov>1.085595</horizontal_fov>
<image>
<width>640</width>
<height>480</height>
<format>R8G8B8</format>
</image>
<clip>
<near>0.03</near>
<far>100</far>
</clip>
</camera>
<plugin name="camera_controller" filename="libgazebo_ros_camera.so">
<alwaysOn>true</alwaysOn>
<updateRate>30.0</updateRate>
<cameraName>/</cameraName>
<frameName>base_camera_link</frameName>
<imageTopicName>image_raw</imageTopicName>
<cameraInfoTopicName>camera_info</cameraInfoTopicName>
<hackBaseline>0.07</hackBaseline>
<distortionK1>0.0</distortionK1>
<distortionK2>0.0</distortionK2>
<distortionK3>0.0</distortionK3>
<distortionT1>0.0</distortionT1>
<distortionT2>0.0</distortionT2>
</plugin>
</sensor>
</gazebo>
</robot>
3.将小车模型文件 myrot.xacro 和 myrot.gazebo.xacro 放到 ~/catkin_ws/src/tutorials/urdf/ 文件夹下
四、ROS 运行环境和小车模型
1.编写 .launch 文件，放到 ~/catkin/src/tutorials/launch 文件夹
gazebo_world.launch：
<launch>
<include file="$(find gazebo_ros)/launch/empty_world.launch">
<arg name="world_name" value="$(find tutorials)/world/room.world"/> // 注意这里是你的地图文件名
<arg name="paused" value="false"/>
<arg name="use_sim_time" value="true"/>
<arg name="gui" value="true"/>
<arg name="headless" value="false"/>
<arg name="debug" value="false"/>
</include>
</launch>
simulation_robot.launch：
<launch>
<arg name="x_pos" default="0.0"/>
<arg name="y_pos" default="0.0"/>
<arg name="z_pos" default="0.0"/>
<param name="/use_sim_time" value="true" />
<include file="$(find tutorials)/launch/gazebo_world.launch"/>
<param name="robot_description" command="$(find xacro)/xacro --inorder $(find tutorials)/urdf/mybot.xacro" />
<node pkg="gazebo_ros" type="spawn_model" name="spawn_urdf" args="-urdf -model mybot.xacro -x $(arg x_pos) -y $(arg y_pos) -z $(arg z_pos) -param robot_description" />
<node name="robot_state_publisher" pkg="robot_state_publisher" type="robot_state_publisher" />
</launch>
2.编写 CMakeLists.txt 和 package.xml 文件
CMakeLists.txt：
cmake_minimum_required(VERSION 2.8.3)
project(tutorials)
find_package(catkin REQUIRED COMPONENTS)
package.xml：
<?xml version="1.0"?>
<package format="2">
<name>tutorials</name>
<version>0.0.0</version>
<description>The tutorials package</description>
<maintainer email="[email protected]">nanorobot</maintainer>
<license>TODO</license>
</package>
3.编写好后，放在 ~/catkin_ws/src/tutorials 文件夹下
4.在 ~/catkin_ws 文件夹下 catkin 编译
catkin build
5.不要忘了 source 一下，否则会报错
source devel/setup.bash
6.运行 launch 文件
roslaunch tutorials simulation_robot.launch
7.运行结果如图：
到这里你的仿真环境和小车都已经搭建完成啦！
五、查看传感器数据
1.首先可以在终端通过 rostopic list 查看 ros 节点数据，我的结果如下
/camera_info
/clock
/cmd_vel
/gazebo/link_states
/gazebo/model_states
/gazebo/parameter_descriptions
/gazebo/parameter_updates
/gazebo/set_link_state
/gazebo/set_model_state
/image_raw // 图像传感器数据节点
/image_raw/compressed
/image_raw/compressed/parameter_descriptions
/image_raw/compressed/parameter_updates
/image_raw/compressedDepth
/image_raw/compressedDepth/parameter_descriptions
/image_raw/compressedDepth/parameter_updates
/image_raw/theora
/image_raw/theora/parameter_descriptions
/image_raw/theora/parameter_updates
/imu
/joint_states
/odom
/parameter_descriptions
/parameter_updates
/rosout
/rosout_agg
/scan // 激光传感器数据节点
/tf
/tf_static
2.然后通过 rviz 可视化查看数据，终端输入 rviz 进入如下界面：
3.修改 frame 为 odom，点击 Add，添加 TF、RobotModel、LaserScan、Image
4.添加后如图所示：
5.修改 LaserScan 和 Image 的 Topic 为 ros 节点的输出，分别为 /Scan 和 /Image_raw，显示结果如图：
至此完成了基于 gazebo 的环境和小车仿真
再次推荐大家去B站观看视频学习，本博客内容大部分参考冰达机器人的B站视频，视频链接如下：