在ROS中开始自主机器人仿真 - 3 建立自己的自主机器人URDF模型

URDF

Unified Robot Description Format

Part 3 建立机器人URDF模型

roslaunch neurobot_description neurobot_rviz.launch

groslaunch neurobot_gazebo neurobot_world.launch

rostopic pub /cmd_vel geometry_msgs/Twist "linear:
x: 0.1
y: 0.0
z: 0.0
angular:
x: 0.0
y: 0.0
z: 0.0"

1. 创建工程

catkin_create_pkg neurobot_description

2. 差分驱动模型

neurobot_description/urdf/
├── macros.xacro   帮助简化的宏
├── materials.xacro  材料说明
├── neurobot.gazebo gazebo具体信息
└── neurobot.xacro URDF 主文件

neurobot.xacro

添加chassis

<link name='chassis'>
<pose>0 0 0.1 0 0 0</pose>

<inertial>
<mass value="15.0"/>
<origin xyz="0.0 0 0.1" rpy=" 0 0 0"/>
<inertia
ixx="0.1" ixy="0" ixz="0"
iyy="0.1" iyz="0"
izz="0.1"
/>
</inertial>

<collision name='collision'>
<geometry>
<box size=".4 .2 .1"/>
</geometry>
</collision>

<visual name='chassis_visual'>
<origin xyz="0 0 0" rpy=" 0 0 0"/>
<geometry>
<box size=".4 .2 .1"/>
</geometry>
</visual>

<collision name='caster_collision'>
<origin xyz="-0.15 0 -0.05" rpy=" 0 0 0"/>
<geometry>
<sphere radius="0.05"/>
</geometry>
<surface>
<friction>
<ode>
<mu>0</mu>
<mu2>0</mu2>
<slip1>1.0</slip1>
<slip2>1.0</slip2>
</ode>
</friction>
</surface>
</collision>

<visual name='caster_visual'>
<origin xyz="-0.15 0 -0.05" rpy=" 0 0 0"/>
<geometry>
<sphere radius="0.05"/>
</geometry>
</visual>

<collision name='caster_front_collision'>
<origin xyz="0.15 0 -0.05" rpy=" 0 0 0"/>
<geometry>
<sphere radius="0.05"/>
</geometry>
<surface>
<friction>
<ode>
<mu>0</mu>
<mu2>0</mu2>
<slip1>1.0</slip1>
<slip2>1.0</slip2>
</ode>
</friction>
</surface>
</collision>

<visual name='caster_front_visual'>
<origin xyz="0.15 0 -0.05" rpy=" 0 0 0"/>
<geometry>
<sphere radius="0.05"/>
</geometry>
</visual>

</link>

添加差分驱动轮子

<link name="left_wheel">
<!--origin xyz="0.1 0.13 0.1" rpy="0 1.5707 1.5707"/-->
<collision name="collision">
<origin xyz="0 0 0" rpy="0 1.5707 1.5707"/>
<geometry>
<cylinder radius="0.1" length="0.05"/>
</geometry>
</collision>
<visual name="left_wheel_visual">
<origin xyz="0 0 0" rpy="0 1.5707 1.5707"/>
<geometry>
<cylinder radius="0.1" length="0.05"/>
</geometry>
</visual>
<inertial>
<origin xyz="0 0 0" rpy="0 1.5707 1.5707"/>
<mass value="5"/>
<inertia
ixx=".1" ixy="0.0" ixz="0.0"
iyy=".1" iyz="0.0"
izz=".1"/>
</inertial>
</link>

添加hinges链接wheels和chassis

<joint type="continuous" name="left_wheel_hinge">
<origin xyz="0 0.15 0" rpy="0 0 0"/>
<!--origin xyz="0.1 0.13 0" rpy="0 1.5707 1.5707"/-->
<child link="left_wheel"/>
<parent link="chassis"/>
<axis xyz="0 1 0" rpy="0 0 0"/>
<limit effort="10000" velocity="1000"/>
<joint_properties damping="1.0" friction="1.0"/>
</joint>

<joint type="continuous" name="right_wheel_hinge">
<origin xyz="0 -0.15 0" rpy="0 0 0"/>
<!--origin xyz="0.1 -0.13 0" rpy="0 1.5707 1.5707"/-->
<child link="right_wheel"/>
<parent link="chassis"/>
<axis xyz="0 1 0" rpy="0 0 0"/>
<limit effort="10000" velocity="1000"/>
<joint_properties damping="1.0" friction="1.0"/>
</joint>

添加camera

<link name="camera">
<collision>
<origin xyz="0 0 0" rpy="0 0 0"/>
<geometry>
<box size="${cameraSize} ${cameraSize} ${cameraSize}"/>
</geometry>
</collision>

<visual>
<origin xyz="0 0 0" rpy="0 0 0"/>
<geometry>
<box size="${cameraSize} ${cameraSize} ${cameraSize}"/>
</geometry>
<material name="green"/>
</visual>

<inertial>
<mass value="${cameraMass}" />
<origin xyz="0 0 0" rpy="0 0 0"/>
<box_inertia m="${cameraMass}" x="${cameraSize}" y="${cameraSize}" z="${cameraSize}" />
<inertia ixx="1e-6" ixy="0" ixz="0" iyy="1e-6" iyz="0" izz="1e-6" />
</inertial>
</link>

<joint name="camera_joint" type="fixed">
<axis xyz="0 1 0" />
<origin xyz=".2 0 0" rpy="0 0 0"/>
<parent link="chassis"/>
<child link="camera"/>
</joint>

添加laser

<joint name="hokuyo_joint" type="fixed">
<axis xyz="0 1 0" />
<origin xyz=".15 0 .1" rpy="0 0 0"/>
<parent link="chassis"/>
<child link="hokuyo"/>
</joint>

<!-- Hokuyo Laser -->
<link name="hokuyo">
<collision>
<origin xyz="0 0 0" rpy="0 0 0"/>
<geometry>
<box size="0.1 0.1 0.1"/>
</geometry>
</collision>

<visual>
<origin xyz="0 0 0" rpy="0 0 0"/>
<geometry>
<mesh filename="package://neurobot_description/meshes/hokuyo.dae"/>
</geometry>
</visual>

<inertial>
<mass value="1e-5" />
<origin xyz="0 0 0" rpy="0 0 0"/>
<inertia ixx="1e-6" ixy="0" ixz="0" iyy="1e-6" iyz="0" izz="1e-6" />
</inertial>
</link>

3. 添加模型插件

neurobot.gazebo

差分驱动

<gazebo>
<plugin name="differential_drive_controller" filename="libgazebo_ros_diff_drive.so">
<legacyMode>false</legacyMode>
<alwaysOn>true</alwaysOn>
<updateRate>10</updateRate>
<leftJoint>left_wheel_hinge</leftJoint>
<rightJoint>right_wheel_hinge</rightJoint>
<wheelSeparation>0.4</wheelSeparation>
<wheelDiameter>0.2</wheelDiameter>
<torque>10</torque>
<commandTopic>cmd_vel</commandTopic>
<odometryTopic>odom</odometryTopic>
<odometryFrame>odom</odometryFrame>
<robotBaseFrame>chassis</robotBaseFrame>
</plugin>
</gazebo>

camera

<gazebo reference="camera">
<material>Gazebo/Green</material>
<sensor type="camera" name="camera1">
<update_rate>30.0</update_rate>
<camera name="head">
<horizontal_fov>1.3962634</horizontal_fov>
<image>
<width>800</width>
<height>800</height>
<format>R8G8B8</format>
</image>
<clip>
<near>0.02</near>
<far>300</far>
</clip>
</camera>
<plugin name="camera_controller" filename="libgazebo_ros_camera.so">
<alwaysOn>true</alwaysOn>
<updateRate>0.0</updateRate>
<cameraName>neurobot/camera1</cameraName>
<imageTopicName>image_raw</imageTopicName>
<cameraInfoTopicName>camera_info</cameraInfoTopicName>
<frameName>camera</frameName>
<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>

laser

<!-- hokuyo -->
<gazebo reference="hokuyo">
<sensor type="gpu_ray" name="head_hokuyo_sensor">
<pose>0 0 0 0 0 0</pose>
<visualize>false</visualize>
<update_rate>40</update_rate>
<ray>
<scan>
<horizontal>
<samples>720</samples>
<resolution>1</resolution>
<min_angle>-1.570796</min_angle>
<max_angle>1.570796</max_angle>
</horizontal>
</scan>
<range>
<min>0.10</min>
<max>30.0</max>
<resolution>0.01</resolution>
</range>
<noise>
<type>gaussian</type>
<!-- Noise parameters based on published spec for Hokuyo laser
achieving "+-30mm" accuracy at range < 10m.  A mean of 0.0m and
stddev of 0.01m will put 99.7% of samples within 0.03m of the true
reading. -->
<mean>0.0</mean>
<stddev>0.01</stddev>
</noise>
</ray>
<plugin name="gazebo_ros_head_hokuyo_controller" filename="libgazebo_ros_gpu_laser.so">
<topicName>/neurobot/laser/scan</topicName>
<frameName>hokuyo</frameName>
</plugin>
</sensor>
</gazebo>

gazebo仿真材料信息

<gazebo reference="chassis">
<material>Gazebo/Orange</material>
</gazebo>

<gazebo reference="left_wheel">
<material>Gazebo/Blue</material>
</gazebo>

<gazebo reference="right_wheel">
<material>Gazebo/Blue</material>
</gazebo>

4.机器人控制

在rviz中查看自己的机器人

roslaunch neurobot_description neurobot_rviz.launch

<?xml version="1.0"?>
<launch>
<param name="robot_description" command="$(find xacro)/xacro.py '$(find mybot_description)/urdf/mybot.xacro'"/>
<!-- send fake joint values -->
<node name="joint_state_publisher" pkg="joint_state_publisher" type="joint_state_publisher">
<param name="use_gui" value="False"/>
</node>
<!-- Combine joint values -->
<node name="robot_state_publisher" pkg="robot_state_publisher" type="state_publisher"/>
<!-- Show in Rviz   -->
<node name="rviz" pkg="rviz" type="rviz"/>
<!--node name="rviz" pkg="rviz" type="rviz" args="-d $(find mybot_description)/launch/myrobot.rviz"/-->
</launch>

在gazebo中加载机器人并控制机器人运动

roslaunch neurobot_gazebo neurobot_world.launch

rostopic list

/cmd_vel  速度控制命令
/neurobot/camera1/image_raw 图像信息
/neurobot/laser/scan 激光数据
/odom 里程计

rostopic pub /cmd_vel geometry_msgs/Twist "linear:
x: 0.1
y: 0.0
z: 0.0
angular:
x: 0.0
y: 0.0
z: 0.0"

keyboard_teleop.launch

keyop.launch

/cmd_vel

References: