A Gentle Introduction to Gazebo Modeling [En/中]

English Version click here

Why yet another Gazebo tutorial？

90% of Gazebo tutorials start with terminal commands that look like this:

gazebo worlds/pioneer2dx.world Gazebo Official Tutorial

Or like this:

roslaunch my_simulations my_world.launch Construct's Gazebo in 5 minutes series

The commands above spawn some given model into Gazebo and surly is a good starting point for a Gazebo beginner. However, few of these tutorials answer a big question: how do you get these models in the first place?

Yes. You can find 3D models from many places made by experts. If you are lucky enough, you may even find the URDF (model) file you need. But what if all you need is a simple, example model for a demo? All these tutorials choose to ignore this problem, which is the reason I wrote this tutorial in the first place: To teach Robotics Engineers how to "model" for Gazebo.

This tutorial targets the following readers:

• Know what is a ROS topic, know how to use rosrun, roslaunch, and can write a simple roslaunch file following examples.
• People who take 3D modeling not as their ultimate goal. That's said, modeling is only a tool for your bigger goal. (This is not a modeling tutorial !)
• The deadline is approaching; you need a simulated demo to present, but you can't find the URDF you need.
• You already found a URDF/XACRO from the others, but have no idea how to edit it.

Index:

• What formats of model does Gazebo need
• How to spawn URDF to Gazebo
• How to create a simple URDF
• How to set a URDF to immovable / transparent / no collision / no gravity
• How to generate URDF with a CAD software (Solidworks / Blender)
• How to make URDF with more details (mesh file)
• How to make URDF with image texture (texture and material)
• How to control the speed and position of a URDF in Gazebo (Gazebo Plugin)
• How to rotate a joint of a URDF in Gazebo (ROS Moveit!)
• How to make a simulated camera and simulated sensors (Gazebo Plugin)

I want to keep this tutorial rolling updated. So if there are contents you would like to see in this tutorial, feel free to submit an issue (or PR and that's even better)!

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Gazebo 模型简明教程

中文版点此

为什么要再写一篇Gazebo教程？

90%的Gazebo模型教程从类似这样的命令行指令开始：

gazebo worlds/pioneer2dx.world (Gazebo 官方教程)

或是类似这样的：

roslaunch my_simulations my_world.launch (Construct 的 《五分钟Gazebo》 系列教程)

上面这些命令是将一些现成的模型文件刷进Gazebo，作为新手的导入并无不妥，但是所有这些教程都没有回答一个至关重要的问题：模型要从哪里来。

你确实可以从许多网站上找到出自专业人士之手的3D模型，如果你运气好，你甚至可以找到你需要的 URDF（模型）文件，但是你需要的只是一个简单的，用于演示的样例模型呢？这些教程无一例外地忽视了这个问题，这也是我写这个教程的初衷，教机器人工程师怎么为 Gazebo 建模。

本文的目标读者如下：

• 知道 ROS topic 是什么，会用 rosrun, roslaunch，能依葫芦画瓢写简单的 roslaunch 文件
• 不以建模为最终目的，即，模型是你用于一个更大目标的一部分（这不是一个建模教程！）
• 死线逐渐逼近，你需要一个仿真演示来交差，但是你找不到现成的 URDF
• 你已经有了一个别人做的 URDF/XACRO ，但是不知道怎么修改它

目录：

• Gazebo 需要什么格式的模型
• 如何将 URDF 导入 Gazebo
• 如何制作简单的 URDF
• 如何将 URDF 设为不动的，透明的，没有碰撞体积的，不受重力影响的
• 如何使用 CAD 软件生成 URDF (Solidworks 或 Blender)
• 如何制作更精细的 URDF (mesh 网格文件)
• 如何制作有贴图的 URDF (texture 纹理 和 material 材质)
• 如何改变 URDF 在 Gazebo 中的速度和位置 (Gazebo Plugin)
• 如何在 Gazebo 中转动 URDF 的关节 (ROS Moveit!)
• 如何制作仿真相机或仿真传感器 (Gazebo Plugin)

未来可能的更多内容：

• 如何抓举：以 Universal Robot 为例
• 如何在 Gazebo 中使用人物模型

我希望这篇教程可以滚动更新，所以如果你有希望在这篇教程中看到的内容，别犹豫，交个issue吧，当然能PR就更好了（