Kinetic 和 Melodic的 xacro 文件语法不同

Gazebo对电脑显卡有一定要求，对Nvida显卡支持较好，对AMD的显卡支持较差，如果是AMD的显卡，复杂的世界模型一般加载不出来

利用spawn_model脚本向gazebo_ros节点（在主题中，空间名为 gazebo）发出服务请求，进而添加 URDF 到 Gazebo 中

rosrun gazebo_ros spawn_model -file `rospack find MYROBOT_description`/urdf/MYROBOT.urdf -urdf -x 0 -y 0 -z 1 -model MYROBOT

如果是.xacro， 可以转化为 urdf 文件：

xacro转urdf

如果是kinetic，执行

rosrun xacro xacro.py robot1.xacro > robot1_processed.urdf

会得到：

xacro: Traditional processing is deprecated. Switch to --inorder processing!
To check for compatibility of your document, use option --check-order.
For more infos, see http://wiki.ros.org/xacro#Processing_Order xacro.py is deprecated; please use xacro instead

说明xacro.py命令已经过期，使用xacro替换： rosrun xacro xacro robot1.xacro > robot1_processed.urdf

---

如果是在Melodic，执行rosrun xacro xacro --inorder $(locate robot.urdf.xacro) > robot_inorder.urdf，结果得到

xacro: in-order processing became default in ROS Melodic. You can drop the option.

查看关节图

先执行sudo apt install -y liburdfdom-tools

check_urdf pr2.urdf
# 再打开转换的pdf
urdf_to_graphiz pr2.urdf

查看spawn_model的所有参数，可以运行：

rosrun gazebo_ros spawn_model -h

在 launch文件中，对于urdf可以这样编写：

<!-- Spawn a robot into Gazebo -->
<node name="spawn_urdf" pkg="gazebo_ros" type="spawn_model" args="-file $(find baxter_description)/urdf/baxter.urdf -urdf -z 1 -model baxter" />

对于xacro，这样编写:

<!-- Convert an xacro and put on parameter server -->
<param name="robot_description" command="$(find xacro)/xacro.py $(find pr2_description)/robots/pr2.urdf.xacro" />

<!-- Spawn a robot into Gazebo -->
<node name="spawn_urdf" pkg="gazebo_ros" type="spawn_model" args="-param robot_description -urdf -model pr2" />

URDF的报错原因：加了等标签，但没加具体内容。

rosrun gazebo_ros spawn_model -file robot.urdf -urdf -model robot

sdf: standard definition of world for Gazebo

<launch>
  <include file="$(find gazebo_ros)/launch/empty_world.launch" >
  </include>

  <arg name='robot_urdf' default="$(find xacro)/xacro '$(find vehicle_simulator)/urdf/robot.urdf.xacro'" />
  <param name="robot_description" command="$(arg robot_urdf)" />
  <node pkg="gazebo_ros" type="spawn_model" name="spawn_robot" args="-urdf -param robot_description -model robot -x 0 -y 0 -z 0.5"/>

  <node pkg="teleop_twist_keyboard" type="teleop_twist_keyboard.py" name="teleop" />
</launch>

Gazebo的gui参数经常是false，这是因为显示界面会显著加大资源占用

world文件可以直接改名称，不影响使用

兼容问题

加入camera仿真

Gazebo只给出了水平FOV, 竖直FOV会根据图片的宽和高自动计算。 Gazebo有函数double VerticalFOV() const，解释: The vertical FOV is calculated from width, height, hfov。有bool SetHorizontalFOV (double _hfov)函数，但是没有函数bool SetVerticalFOV (double _hfov)

差速模块

出现下面日志，说明差速控制模块正常加载。

[ INFO] [1720590402.172629168, 68.803000000]: Starting plugin DiffDrive(ns = //)
[ INFO] [1720590402.172729086, 68.803000000]: DiffDrive(ns = //): <rosDebugLevel> = na
[ INFO] [1720590402.173268546, 68.803000000]: DiffDrive(ns = //): <tf_prefix> = 
[ INFO] [1720590402.173831755, 68.803000000]: DiffDrive(ns = //): Try to subscribe to cmd_vel
[ INFO] [1720590402.175204165, 68.803000000]: DiffDrive(ns = //): Subscribe to cmd_vel
[ INFO] [1720590402.175652313, 68.803000000]: DiffDrive(ns = //): Advertise odom on odom

libgazebo_ros_gps_sensor.so

libgazebo_ros_bumper.so

libgazebo_ros_ray_sensor.so