Gazebo Modeling

Youtube

https://www.youtube.com/watch?v=CsxK1maWJoI

1.How to modeling in sdf file(sdf 파일로 모델링하는 법)

comment(주석) : comment command(주석처리 명령어)

<!-- comment(주석할 내용) -->

xml version : usually write xml version="1.0"

<?xml version="1.0"?>

sdf version : usually write sdf version="1.5"

<sdf version="1.5">  

model name : 모델 이름은 폴더내용과 일치해야함

<model name="folder name"> 

link name : Each model link name (모델의 각 링크의 이름)

<link name="any name"> 

inertial : Choose center of mass, inertial, mass(중심 좌표, 관성 모멘트, 질량)

<inertial> 
  <pose>0 0 0.06 0 0 0</pose>
  <inertia>
    <ixx>0.001</ixx>
    <ixy>0.000</ixy>
    <ixz>0.000</ixz>
    <iyy>0.001</iyy>
    <iyz>0.000</iyz>
    <izz>0.001</izz>
  </inertia>
  <mass>1.0</mass>
</inertial>

collision : Choose collision area(충돌 영역 정하기)

collision name : Choose collision name

<collision name="base_collision">

pose : Choose x,y,z,row,pitch,yaw

<pose>0 0 0.06 0 0 0</pose>

geometry : Choose shape

<box>
    <size>0.265 0.265 0.1</size>
</box>

<sphere>
     <radius>0.005000</radius>
</sphere>

<cylinder>
     <radius>0.0508</radius>
     <length>0.055</length>
</cylinder>

surface : Choose friction(마찰력 정함)

<surface>
 <friction>
     <ode>
         <mu>100000.0</mu>
         <mu2>100000.0</mu2>
         <fdir1>0 0 0</fdir1>
         <slip1>0</slip1>
         <slip2>0</slip2>
     </ode>
 </friction>
</surface>    

Example :

<collision name="base_collision">
        <pose>0 0 0.06 0 0 0</pose>
        <geometry>
            <box>
                <size>0.265 0.265 0.1</size>
            </box>
        </geometry>            
        <surface>
            <friction>
                 <ode>
                     <mu>100000.0</mu>
                     <mu2>100000.0</mu2>
                     <fdir1>0 0 0</fdir1>
                     <slip1>0</slip1>
                     <slip2>0</slip2>
                 </ode>
            </friction>
        </surface>
</collision>

visual : Modeling(stl,dae 파일도 넣을 수 있다)

<visual name="name"> {same as collision} </visual>

Example(No stl file)

<visual name="left_wheel_visual">
     <pose>0.07 0.11 0.033 -1.57 0 0</pose>
     <geometry>
           <cylinder>
               <radius>0.033</radius>
               <length>0.018</length>
          </cylinder>
     </geometry>
</visual>

Example(stl or dae file)

<visual name="lidar_sensor_visual">
    <pose>-0.012 0 0.14 0 0 0</pose>
    <geometry>
         <mesh>
             <uri>model://{model_file}/meshes/{visual model}.dae</uri>
             <scale>0.001 0.001 0.001</scale>
         </mesh>
    </geometry>
</visual>

sensor : 현재 공부 중(studying)

2.How to modeling in urdf file(urdf 파일로 모델링하는 법)

xml version : same as sdf file(sdf 파일과 똑같음)

robot name : Choose robot name

write xmlns:xacro="http://ros.org/wiki/xacro" (Don't know reason)

<robot name="{Your robot name}" xmlns:xacro="http://ros.org/wiki/xacro">

Interworking with another xacro files(다른 xacro 파일 연동하는 법)

<xacro:include filename="$(find directory name)/{path}/another file.xacro"/>

Joint name : Choose your model link name and type

type : continuous, revolute, fixed

<joint name="base_joint" type="fixed">

parent link : choose parent link

child link : choose child link

: 부모 링크 좌표 기준으로 자식 링크 초기 좌표가 정해진다.

<parent link="base_footprint" />
<child link="base_link" />

Link name : Choose your model link name

<link name="Robot link name" />

visual : Modeling(stl,dae 파일도 넣을 수 있음)

origin : Choose raw,pitch,yaw,x,y,z

<origin rpy="0 0 0" xyz="0 0 0.0" />

geometry : Choose shape(모양 만들기)

<geometry>
    <box size="0.265 0.265 0.1" />
    <sphere radius="0.005" />
    <cylinder length="0.018" radius="0.033" />
</geometry>

material : Usually choose color(색깔 정할 때 주로 씀)

<material name="light_black" />

Example

<visual>
     <origin rpy="0 0 0" xyz="0 0 0.0" />
     <geometry>
         <box size="0.265 0.265 0.1" />
     </geometry>
     <material name="light_black" />
</visual>

<visual>
     <origin rpy="0 0 0" xyz="0 0 0" />
     <geometry>
         <mesh filename="package://turtlebot3_description/meshes/sensors/lds.stl" scale="0.001 0.001 0.001" />
     </geometry>
     <material name="dark" />
</visual>

collision : Choose collision area 충돌영역 정하기(visual과 똑같음)

<collision>
   <origin rpy="0 0 0" xyz="0 0 0" />
   <geometry>
       <box size="0.265 0.265 0.1" />
   </geometry>
</collision>

inertial : Choose center of mass, mass, inertia(중심무게, 질량, 관성모멘트)

<inertial>
      <origin xyz="0.05 0 0" />
      <mass value="0.01" />
      <inertia ixx="1.6425e-6" ixy="0" ixz="0" iyy="1.6425e-6" iyz="0" izz="1.125e-6" />
</inertial>

Full Example

<link name="joint2_right_link">
    <visual>
        <origin rpy="0 0 0" xyz="0 0 0" />
        <geometry>
            <cylinder length="0.018" radius="0.015" />
        </geometry>
        <material name="dark" />
    </visual>
    <collision>
        <origin rpy="0 0 0" xyz="0 0 0" />
        <geometry>
            <cylinder length="0.018" radius="0.015" />
        </geometry>
    </collision>
    <visual>
        <origin rpy="0 0 0" xyz="0.05 0 0" />
        <geometry>
            <box size="0.1 0.03 0.03" />
        </geometry>
        <material name="dark" />
    </visual>
    <collision>
        <origin rpy="0 0 0" xyz="0.05 0 0" />
        <geometry>
            <box size="0.1 0.03 0.03" />
        </geometry>
    </collision>
    
    <inertial>
        <origin xyz="0.05 0 0" />
        <mass value="0.01" />
        <inertia ixx="1.6425e-6" ixy="0" ixz="0" iyy="1.6425e-6" iyz="0" izz="1.125e-6" />
    </inertial>
</link>

transmission : Making a joint moving(Joint 움직이게 해줌)

<transmission name="trans_{joint name}">

type

 <type>transmission_interface/SimpleTransmission</type>

joint : same joint name

<joint name="joint1_left_joint">{}</joint>

hardwareInterface : Joint 방식

<joint name="joint1_left_joint">
    <hardwareInterface>hardware_interface/EffortJointInterface</hardwareInterface>
</joint>