【kinetic】操作系统探索总结（六）使用smartcar进行仿真

　　之前的博客中，我们使用rviz进行了TurtleBot的仿真，而且使用urdf文件建立了自己的机器人smartcar，本篇博客是将两者进行结合，使用smartcar机器人在rviz中进行仿真。

　　一、模型完善

　　之前我们使用的都是urdf文件格式的模型，在很多情况下，ROS对urdf文件的支持并不是很好，使用宏定义的.xacro文件兼容性更好，扩展性也更好。所以我们把之前的urdf文件重新整理编写成.xacro文件。

　　.xacro文件主要分为三部分(以下文件均创建在urdf文件夹下，上一章节创建的文件可以删除)：

　　1、机器人主体(smartcar_body.urdf.xacro)

　　

<?xml version="1.0"?>  
<robot name="smartcar" xmlns:xacro="http://ros.org/wiki/xacro">  
  <xacro:property name="M_PI" value="3.14159"/>    
  
  <!-- Macro for SmartCar body. Including Gazebo extensions, but does not include Kinect -->  
  <xacro:include filename="$(find smartcar_description)/urdf/gazebo.urdf.xacro"/>  
  
  <xacro:property name="base_x" value="0.33" />  
  <xacro:property name="base_y" value="0.33" />  
  
  <xacro:macro name="smartcar_body">  
    
    <link name="base_link">  
    <inertial>  
      <origin xyz="0 0 0.055"/>  
      <mass value="1.0" />  
      <inertia ixx="1.0" ixy="0.0" ixz="0.0" iyy="1.0" iyz="0.0" izz="1.0"/>  
    </inertial>  
    <visual>  
      <geometry>  
        <box size="0.25 .16 .05"/>  
      </geometry>  
      <origin rpy="0 0 0" xyz="0 0 0.055"/> 
      <material name="blue">  
      <color rgba="0 0 .8 1"/>  
      </material>  
   </visual>  
   <collision>  
      <origin rpy="0 0 0" xyz="0 0 0.055"/>  
      <geometry>  
        <box size="0.25 .16 .05" />  
      </geometry>  
    </collision>  
  </link>  

 <link name="left_front_wheel">  
    <inertial>  
      <origin  xyz="0.08 0.08 0.025"/>  
      <mass value="0.1" />  
       <inertia ixx="1.0" ixy="0.0" ixz="0.0" iyy="1.0" iyz="0.0" izz="1.0"/>  
    </inertial>  

    <visual>  
      <geometry>  
        <cylinder length=".02" radius="0.025"/>  
      </geometry>  
      <material name="black">  
        <color rgba="0 0 0 1"/>  
      </material>  
    </visual>  
    <collision>  
      <origin rpy="0 1.57075 1.57075" xyz="0.08 0.08 0.025"/>  
      <geometry>  
         <cylinder length=".02" radius="0.025"/>  
      </geometry>  
    </collision>  
  </link>  

  <joint name="left_front_wheel_joint" type="continuous">  
    <axis xyz="0 0 1"/>  
    <parent link="base_link"/>  
    <child link="left_front_wheel"/>  
    <origin rpy="0 1.57075 1.57075" xyz="0.08 0.08 0.025"/>  
    <limit effort="100" velocity="100"/>  
    <joint_properties damping="0.0" friction="0.0"/>  
  </joint>  

  <link name="right_front_wheel">  
    <inertial>  
      <origin xyz="0.08 -0.08 0.025"/>  
      <mass value="0.1" />  
       <inertia ixx="1.0" ixy="0.0" ixz="0.0" iyy="1.0" iyz="0.0" izz="1.0"/>  
    </inertial>  

    <visual>  
      <geometry>  
        <cylinder length=".02" radius="0.025"/>  
      </geometry>  

      <material name="black">  
        <color rgba="0 0 0 1"/>  
      </material>  
    </visual>  

    <collision>  
      <origin rpy="0 1.57075 1.57075" xyz="0.08 -0.08 0.025"/>  
      <geometry>  
         <cylinder length=".02" radius="0.025"/>  
      </geometry>  
    </collision>  
  </link>  

  <joint name="right_front_wheel_joint" type="continuous">  
    <axis xyz="0 0 1"/>  
    <parent link="base_link"/>  
    <child link="right_front_wheel"/>  
    <origin rpy="0 1.57075 1.57075" xyz="0.08 -0.08 0.025"/>  
    <limit effort="100" velocity="100"/>  
    <joint_properties damping="0.0" friction="0.0"/>  
 </joint>  

 <link name="left_back_wheel">  
    <inertial>  
      <origin xyz="-0.08 0.08 0.025"/>  
      <mass value="0.1" />  
       <inertia ixx="1.0" ixy="0.0" ixz="0.0" iyy="1.0" iyz="0.0" izz="1.0"/>  
    </inertial>  

    <visual>  
      <geometry>  
        <cylinder length=".02" radius="0.025"/>  
      </geometry>  
      <material name="black">  
        <color rgba="0 0 0 1"/>  
      </material>  
   </visual>  

   <collision>  
       <origin rpy="0 1.57075 1.57075" xyz="-0.08 0.08 0.025"/>  
      <geometry>  
         <cylinder length=".02" radius="0.025"/>  
      </geometry>  
    </collision>  
  </link>  

  <joint name="left_back_wheel_joint" type="continuous">  
    <axis xyz="0 0 1"/>  
    <parent link="base_link"/>  
    <child link="left_back_wheel"/>  
    <origin rpy="0 1.57075 1.57075" xyz="-0.08 0.08 0.025"/>  
    <limit effort="100" velocity="100"/>  
    <joint_properties damping="0.0" friction="0.0"/>  
  </joint>  

  <link name="right_back_wheel">  

    <inertial>  
       <origin xyz="-0.08 -0.08 0.025"/>  
       <mass value="0.1" />  
       <inertia ixx="1.0" ixy="0.0" ixz="0.0" iyy="1.0" iyz="0.0" izz="1.0"/>  
    </inertial>  

    <visual>  
      <geometry>  
        <cylinder length=".02" radius="0.025"/>  
      </geometry>  
      <material name="black">  
        <color rgba="0 0 0 1"/>  
      </material>  
   </visual>  
   <collision>  
      <origin rpy="0 1.57075 1.57075" xyz="-0.08 -0.08 0.025"/>  
      <geometry>  
         <cylinder length=".02" radius="0.025"/>  
      </geometry>  
    </collision>  
  </link>  
  <joint name="right_back_wheel_joint" type="continuous">  

    <axis xyz="0 0 1"/>  

    <parent link="base_link"/>  

    <child link="right_back_wheel"/>  

    <origin rpy="0 1.57075 1.57075" xyz="-0.08 -0.08 0.025"/>  

    <limit effort="100" velocity="100"/>  

    <joint_properties damping="0.0" friction="0.0"/>  

  </joint>  

  <link name="head">  

    <inertial>  

      <origin xyz="0.08 0 0.08"/>  

      <mass value="0.1" />  

      <inertia ixx="1.0" ixy="0.0" ixz="0.0" iyy="1.0" iyz="0.0" izz="1.0"/>  

    </inertial>  

    <visual>  
      <geometry>  
        <box size=".02 .03 .03"/>  
      </geometry>  

      <material name="white">  
        <color rgba="1 1 1 1.5"/>  
      </material>  
     </visual>  
     <collision>  
      <origin xyz="0.08 0 0.08"/>  
      <geometry>  
         <cylinder length=".02" radius="0.025"/>  
      </geometry>  
    </collision>  
  </link>  
  <joint name="tobox" type="fixed">  
    <parent link="base_link"/>  
    <child link="head"/>  
    <origin xyz="0.08 0 0.08"/>  
  </joint>  
  </xacro:macro>  
</robot>

 

 

 

　　2、gazebo属性部分（gazebo.urdf.xacro）　　

<?xml version="1.0"?>  
<robot xmlns:controller="http://playerstage.sourceforge.net/gazebo/xmlschema/#controller"   
    xmlns:interface="http://playerstage.sourceforge.net/gazebo/xmlschema/#interface"   
    xmlns:sensor="http://playerstage.sourceforge.net/gazebo/xmlschema/#sensor"   
    xmlns:xacro="http://ros.org/wiki/xacro" 
    name="smartcar_gazebo">  

<!-- ASUS Xtion PRO camera for simulation -->  
<!-- gazebo_ros_wge100 plugin is in kt2_gazebo_plugins package -->  

<xacro:macro name="smartcar_sim">  
    <gazebo reference="base_link">  
        <material>Gazebo/Blue</material>  
    </gazebo>  

    <gazebo reference="right_front_wheel">  
        <material>Gazebo/FlatBlack</material>  
    </gazebo>  
 
    <gazebo reference="right_back_wheel">  
        <material>Gazebo/FlatBlack</material>  
    </gazebo>  

    <gazebo reference="left_front_wheel">  
        <material>Gazebo/FlatBlack</material>  
    </gazebo>  

    <gazebo reference="left_back_wheel">  
        <material>Gazebo/FlatBlack</material>  
    </gazebo>  

    <gazebo reference="head">  
        <material>Gazebo/White</material>  
    </gazebo>  

</xacro:macro>  

</robot>

 

　　3、主文件（smartcar.urdf.xacro）

　　

<?xml version="1.0"?>  
<robot name="smartcar"    

    xmlns:xi="http://www.w3.org/2001/XInclude"  
    xmlns:gazebo="http://playerstage.sourceforge.net/gazebo/xmlschema/#gz"  
    xmlns:model="http://playerstage.sourceforge.net/gazebo/xmlschema/#model"  
    xmlns:sensor="http://playerstage.sourceforge.net/gazebo/xmlschema/#sensor"  
    xmlns:body="http://playerstage.sourceforge.net/gazebo/xmlschema/#body"  
    xmlns:geom="http://playerstage.sourceforge.net/gazebo/xmlschema/#geom"  
    xmlns:joint="http://playerstage.sourceforge.net/gazebo/xmlschema/#joint"  
    xmlns:controller="http://playerstage.sourceforge.net/gazebo/xmlschema/#controller"  
    xmlns:interface="http://playerstage.sourceforge.net/gazebo/xmlschema/#interface"  
    xmlns:rendering="http://playerstage.sourceforge.net/gazebo/xmlschema/#rendering"  
    xmlns:renderable="http://playerstage.sourceforge.net/gazebo/xmlschema/#renderable"  
    xmlns:physics="http://playerstage.sourceforge.net/gazebo/xmlschema/#physics"  
    xmlns:xacro="http://ros.org/wiki/xacro">  

  <include filename="$(find smartcar_description)/urdf/smartcar_body.urdf.xacro" />  

  <!-- Body of SmartCar, with plates, standoffs and Create (including sim sensors) -->  
  <smartcar_body/>  
  <smartcar_sim/>  
</robot>

 

 

 

二、lanuch文件(smartcar_display.rviz.launch)

　　在launch文件中要启动节点和模拟器。　　

<launch>
   <param name="/use_sim_time" value="false" />
   <!-- Load the URDF/Xacro model of our robot -->
   <arg name="urdf_file" default="$(find xacro)/xacro '$(find smartcar_description)/urdf/smartcar.urdf.xacro' --inorder" />
   <arg name="gui" default="false" />
   <param name="robot_description" command="$(arg urdf_file)" />
   <param name="use_gui" value="$(arg gui)"/>

   <node name="arbotix" pkg="arbotix_python" type="arbotix_driver" output="screen">
       <param name="sim" value="true"/>
   </node>

    <node name="joint_state_publisher" pkg="joint_state_publisher" type="joint_state_publisher" >
    </node>

    <node name="robot_state_publisher" pkg="robot_state_publisher" type="state_publisher">
        <param name="publish_frequency" type="double" value="20.0" />
    </node>

     <!-- We need a static transforms for the wheels -->
    <node pkg="tf" type="static_transform_publisher" name="odom_left_wheel_broadcaster" args="0 0 0 0 0 0 /base_link /left_front_link 100" />
    <node pkg="tf" type="static_transform_publisher" name="odom_right_wheel_broadcaster" args="0 0 0 0 0 0 /base_link /right_front_link 100" />

   <node name="rviz" pkg="rviz" type="rviz" args="-d $(find smartcar_description)/urdf.rviz" />  

</launch>

 

 再在smartcar_description文件夹下的config文件夹中建立下面的文件

　　(如果不想进行这一步，把launch文件中的

　　　　<rosparam file="$(find smartcar_description)/config/smartcar_arbotix.yaml" command="load" /> 

　　这行代码注释即可。)：

$ cd ~/catkin_ws/src/config
$ touch smartcar_arbotix.yaml

把下面的代码粘进去。

port: /dev/ttyUSB0
baud: 115200
rate: 20
sync_write: True
sync_read: True
read_rate: 20
write_rate: 20

controllers: {
   #  Pololu motors: 1856 cpr = 0.3888105m travel = 4773 ticks per meter (empirical: 4100)
   base_controller: {type: diff_controller, base_frame_id: base_link, base_width: 0.26, ticks_meter: 4100, Kp: 12, Kd: 12, Ki: 0, Ko: 50, accel_limit: 1.0 }
}

 
复制使用cp指令将/opt/ros/kinetic/share/urdf_tutorial 目录下的 urdf.rviz拷贝到项目目录 ~/catkin_ws/src/smartcar_description 下

三、仿真测试

　　首先运行lanuch，既可以看到rviz中的机器人：

roslaunch smartcar_description smartcar_display.rviz.launch 

rostopic pub -1 /cmd_vel geometry_msgs/Twist '{}'  《停止运动》

 

 

发布一条动作的消息。

    01.rostopic pub -r 10 /cmd_vel geometry_msgs/Twist '{linear: {x: 0.5, y: 0, z: 0}, angular: {x: 0, y: 0, z: 0.5}}'

 却发现是一个坐标轴在运动。这明显和我们想要的结果不同。

这里，我们需要对rviz客户端进行设置。

将Global Options下的Fixed Frame更改为odom,这样我们的小车就能正常的运行了。

但是，我们之前的历程中有指示小车的方向，这里要怎么设置呢？我们需要在窗口的左下角的Add按钮中添加 Odometry模块，并选中话题odom。

下面我们选中rviz窗口，按下Ctrl+S，将会把当前的设置保存到urdf.rviz文件中。

保存后的urdf.rviz的内容如下:

Panels:
  - Class: rviz/Displays
    Help Height: 78
    Name: Displays
    Property Tree Widget:
      Expanded:
        - /Global Options1
        - /Status1
        - /RobotModel1
        - /RobotModel1/Links1
        - /TF1
        - /TF1/Tree1/odom1
        - /TF1/Tree1/odom1/base_link1
      Splitter Ratio: 0.5
    Tree Height: 561
  - Class: rviz/Selection
    Name: Selection
  - Class: rviz/Tool Properties
    Expanded:
      - /2D Pose Estimate1
      - /2D Nav Goal1
      - /Publish Point1
    Name: Tool Properties
    Splitter Ratio: 0.588679016
  - Class: rviz/Views
    Expanded:
      - /Current View1
    Name: Views
    Splitter Ratio: 0.5
  - Class: rviz/Time
    Experimental: false
    Name: Time
    SyncMode: 0
    SyncSource: ""
Visualization Manager:
  Class: ""
  Displays:
    - Alpha: 0.5
      Cell Size: 1
      Class: rviz/Grid
      Color: 160; 160; 164
      Enabled: true
      Line Style:
        Line Width: 0.0299999993
        Value: Lines
      Name: Grid
      Normal Cell Count: 0
      Offset:
        X: 0
        Y: 0
        Z: 0
      Plane: XY
      Plane Cell Count: 10
      Reference Frame: <Fixed Frame>
      Value: true
    - Alpha: 0.5
      Class: rviz/RobotModel
      Collision Enabled: false
      Enabled: true
      Links:
        All Links Enabled: true
        Expand Joint Details: false
        Expand Link Details: false
        Expand Tree: false
        Link Tree Style: Links in Alphabetic Order
        base_link:
          Alpha: 1
          Show Axes: false
          Show Trail: false
          Value: true
        head:
          Alpha: 1
          Show Axes: false
          Show Trail: false
          Value: true
        left_back_wheel:
          Alpha: 1
          Show Axes: false
          Show Trail: false
          Value: true
        left_front_wheel:
          Alpha: 1
          Show Axes: false
          Show Trail: false
          Value: true
        right_back_wheel:
          Alpha: 1
          Show Axes: false
          Show Trail: false
          Value: true
        right_front_wheel:
          Alpha: 1
          Show Axes: false
          Show Trail: false
          Value: true
      Name: RobotModel
      Robot Description: robot_description
      TF Prefix: ""
      Update Interval: 0
      Value: true
      Visual Enabled: true
    - Class: rviz/TF
      Enabled: true
      Frame Timeout: 15
      Frames:
        All Enabled: true
        base_link:
          Value: true
        head:
          Value: true
        left_back_wheel:
          Value: true
        left_front_link:
          Value: true
        left_front_wheel:
          Value: true
        odom:
          Value: true
        right_back_wheel:
          Value: true
        right_front_link:
          Value: true
        right_front_wheel:
          Value: true
      Marker Scale: 0.5
      Name: TF
      Show Arrows: true
      Show Axes: true
      Show Names: true
      Tree:
        odom:
          base_link:
            head:
              {}
            left_back_wheel:
              {}
            left_front_link:
              {}
            left_front_wheel:
              {}
            right_back_wheel:
              {}
            right_front_link:
              {}
            right_front_wheel:
              {}
      Update Interval: 0
      Value: true
    - Angle Tolerance: 0.100000001
      Class: rviz/Odometry
      Covariance:
        Orientation:
          Alpha: 0.5
          Color: 255; 255; 127
          Color Style: Unique
          Frame: Local
          Offset: 1
          Scale: 1
          Value: true
        Position:
          Alpha: 0.300000012
          Color: 204; 51; 204
          Scale: 1
          Value: true
        Value: true
      Enabled: true
      Keep: 100
      Name: Odometry
      Position Tolerance: 0.100000001
      Shape:
        Alpha: 1
        Axes Length: 1
        Axes Radius: 0.100000001
        Color: 255; 25; 0
        Head Length: 0.300000012
        Head Radius: 0.100000001
        Shaft Length: 1
        Shaft Radius: 0.0500000007
        Value: Arrow
      Topic: /odom
      Unreliable: false
      Value: true
  Enabled: true
  Global Options:
    Background Color: 48; 48; 48
    Default Light: true
    Fixed Frame: odom
    Frame Rate: 30
  Name: root
  Tools:
    - Class: rviz/Interact
      Hide Inactive Objects: true
    - Class: rviz/MoveCamera
    - Class: rviz/Select
    - Class: rviz/FocusCamera
    - Class: rviz/Measure
    - Class: rviz/SetInitialPose
      Topic: /initialpose
    - Class: rviz/SetGoal
      Topic: /move_base_simple/goal
    - Class: rviz/PublishPoint
      Single click: true
      Topic: /clicked_point
  Value: true
  Views:
    Current:
      Class: rviz/Orbit
      Distance: 6.47174978
      Enable Stereo Rendering:
        Stereo Eye Separation: 0.0599999987
        Stereo Focal Distance: 1
        Swap Stereo Eyes: false
        Value: false
      Focal Point:
        X: 0
        Y: 0
        Z: 0
      Focal Shape Fixed Size: true
      Focal Shape Size: 0.0500000007
      Invert Z Axis: false
      Name: Current View
      Near Clip Distance: 0.00999999978
      Pitch: 0.695397019
      Target Frame: <Fixed Frame>
      Value: Orbit (rviz)
      Yaw: 0.513581991
    Saved: ~
Window Geometry:
  Displays:
    collapsed: false
  Height: 848
  Hide Left Dock: false
  Hide Right Dock: false
  QMainWindow State: 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
  Selection:
    collapsed: false
  Time:
    collapsed: false
  Tool Properties:
    collapsed: false
  Views:
    collapsed: false
  Width: 1216
  X: 65
  Y: 24