gazebo和moveit联合机械臂运动规划仿真(包含realsense视觉点云)

2023-05-16

1、gazebo仿真环境搭建

最终的场景：
在这里插入图片描述

使用的机械臂：AR3工业六轴机械臂
系统环境： ubuntu18 + ros-melodic
注：机械臂description包在github上下载的, 自己又对gazebo环境做了相应的修改。
下面是用到的主要的urdf描述文件：

<?xml version="1.0" encoding="utf-8"?>
<!-- =================================================================================== -->
<!-- |    This document was autogenerated by xacro from ar3.urdf                       | -->
<!-- |    EDITING THIS FILE BY HAND IS NOT RECOMMENDED but it was unfortunately        | -->
<!-- =================================================================================== -->
<robot name="ar3" xmlns:xacro="http://www.ros.org/wiki/xacro">

  <material name="SwivelWhite">    <color rgba="1.0 1.0 1.0 1"/></material>
  <material name="SwivelLightGray"><color rgba="0.8 0.8 0.8 1"/></material>
  <material name="SwivelMedGray">  <color rgba="0.6 0.6 0.6 1"/></material>
  <material name="SwivelDarkGray"> <color rgba="0.4 0.4 0.4 1"/></material>
  <material name="SwivelRed">      <color rgba="0.5 0.4 0.4 1"/></material>
  <material name="SwivelGreen">    <color rgba="0.4 0.5 0.4 1"/></material>
  <material name="SwivelBlue">     <color rgba="0.4 0.4 0.5 1"/></material>

  <xacro:property name = "pi" value = "3.1415927" />

  <xacro:include filename="$(find realsense_ros_gazebo)/xacro/tracker.xacro"/>
  <xacro:include filename="$(find realsense_ros_gazebo)/xacro/depthcam.xacro"/>
        
  <xacro:realsense_d435 sensor_name="d435" parent_link="base_link" rate="10">
    <origin rpy="${pi/2} ${pi/2} 0 " xyz="0 -0.35 0.7"/>
  </xacro:realsense_d435>


  <link name="world" />

  <link name="base_link">
    <inertial>
      <origin rpy="0 0 0" xyz="-4.6941E-06 0.054174 0.038824"/>
      <mass value="0.7102"/>
      <inertia ixx="0.0039943" ixy="3.697E-07" ixz="-5.7364E-08" iyy="0.0014946" iyz="-0.00036051" izz="0.0042554"/>
    </inertial>
    <visual>
      <origin rpy="0 0 0" xyz="0 0 0"/>
      <geometry>
        <mesh filename="package://ar3_description/meshes/base_link.STL"/>
      </geometry>
      <material name="">
        <color rgba="1 1 0 1"/>
      </material>
    </visual>
    <collision>
      <origin rpy="0 0 0" xyz="0 0 0"/>
      <geometry>
        <mesh filename="package://ar3_description/meshes/base_link.STL"/>
      </geometry>
    </collision>
  </link>

  <joint name="joint_world" type="fixed">
    <parent link="world"/>
    <child link="base_link"/>
    <origin xyz="0 0 0" rpy="0 0 0" />  
  </joint>

  <link name="link_1">
    <inertial>
      <origin rpy="0 0 0" xyz="-0.022706 0.04294 -0.12205"/>
      <mass value="0.88065"/>
      <inertia ixx="0.0034" ixy="0.00042296" ixz="-0.00089231" iyy="0.0041778" iyz="0.0010848" izz="0.0027077"/>
    </inertial>
    <visual>
      <origin rpy="0 0 0" xyz="0 0 0"/>
      <geometry>
        <mesh filename="package://ar3_description/meshes/link_1.STL"/>
      </geometry>
      <material name="">
        <color rgba="1 1 0 1"/>
      </material>
    </visual>
    <collision>
      <origin rpy="0 0 0" xyz="0 0 0"/>
      <geometry>
        <mesh filename="package://ar3_description/meshes/link_1.STL"/>
      </geometry>
    </collision>
  </link>

  <joint name="joint_1" type="revolute">
    <origin rpy="${pi} 0 0" xyz="0 0 0.003445"/>
    <parent link="base_link"/>
    <child link="link_1"/>
    <axis xyz="0 0 1"/>
    <limit lower="-2.96706" upper="2.96706" effort="100" velocity="100"/>
  </joint>

  <link name="link_2">
    <inertial>
      <origin rpy="0 0 0" xyz="0.064818 -0.11189 -0.038671"/>
      <mass value="0.57738"/>
      <inertia ixx="0.0047312" ixy="0.0022624" ixz="0.00032144" iyy="0.0020836" iyz="-0.00056569" izz="0.0056129"/>
    </inertial>
    <visual>
      <origin rpy="0 0 0" xyz="0 0 0"/>
      <geometry>
        <mesh filename="package://ar3_description/meshes/link_2.STL"/>
      </geometry>
      <material name="">
        <color rgba="1 1 0 1"/>
      </material>
    </visual>
    <collision>
      <origin rpy="0 0 0" xyz="0 0 0"/>
      <geometry>
        <mesh filename="package://ar3_description/meshes/link_2.STL"/>
      </geometry>
    </collision>
  </link>

  <joint name="joint_2" type="revolute">
    <origin rpy="1.5708 0.5236 -1.5708" xyz="0 0.064146 -0.16608"/>
    <parent link="link_1"/>
    <child link="link_2"/>
    <axis xyz="0 0 -1"/>
    <limit lower="${-39.6 / 180.0 * pi}" upper="${pi / 2.0}" effort="100" velocity="100"/>
  </joint>

  <link name="link_3">
    <inertial>
      <origin rpy="0 0 0" xyz="-0.00029765 -0.023661 -0.0019125"/>
      <mass value="0.1787"/>
      <inertia ixx="0.0001685" ixy="-2.7713E-05" ixz="5.6885E-06" iyy="0.00012865" iyz="2.9256E-05" izz="0.00020744"/>
    </inertial>
    <visual>
      <origin rpy="0 0 0" xyz="0 0 0"/>
      <geometry>
        <mesh filename="package://ar3_description/meshes/link_3.STL"/>
      </geometry>
      <material name="">
        <color rgba="1 1 0 1"/>
      </material>
    </visual>
    <collision>
      <origin rpy="0 0 0" xyz="0 0 0"/>
      <geometry>
        <mesh filename="package://ar3_description/meshes/link_3.STL"/>
      </geometry>
    </collision>
  </link>

  <joint name="joint_3" type="revolute">
    <origin rpy="0 0 -1.04720367321" xyz="0.1525 -0.26414 0"/>
    <parent link="link_2"/>
    <child link="link_3"/>
    <axis xyz="0 0 -1"/>
    <limit lower="0.0174533" upper="2.5080381" effort="100" velocity="100"/>
  </joint>

  <link name="link_4">
    <inertial>
      <origin rpy="0 0 0" xyz="-0.0016798 -0.00057319 -0.074404"/>
      <mass value="0.34936"/>
      <inertia ixx="0.0030532" ixy="-1.8615E-05" ixz="-7.0047E-05" iyy="0.0031033" iyz="-2.3301E-05" izz="0.00022264"/>
    </inertial>
    <visual>
      <origin rpy="0 0 0" xyz="0 0 0"/>
      <geometry>
        <mesh filename="package://ar3_description/meshes/link_4.STL"/>
      </geometry>
      <material name="">
        <color rgba="1 1 0 1"/>
      </material>
    </visual>
    <collision>
      <origin rpy="0 0 0" xyz="0 0 0"/>
      <geometry>
        <mesh filename="package://ar3_description/meshes/link_4.STL"/>
      </geometry>
    </collision>
  </link>  

  <joint name="joint_4" type="revolute">
    <origin rpy="1.5708 -1.2554 -1.5708" xyz="0 0 0.00675"/>
    <parent link="link_3"/>
    <child link="link_4"/>
    <axis xyz="0 0 -1"/>
    <limit lower="-2.8710666" upper="2.8710666" effort="100" velocity="100"/>
  </joint>

  <link name="link_5">
    <inertial>
      <origin rpy="0 0 0" xyz="0.0015066 -1.3102E-05 -0.012585"/>
      <mass value="0.11562"/>
      <inertia ixx="5.5035E-05" ixy="-1.019E-08" ixz="-2.6243E-06" iyy="8.2921E-05" iyz="1.4437E-08" izz="5.2518E-05"/>
    </inertial>
    <visual>
      <origin rpy="0 0 0" xyz="0 0 0"/>
      <geometry>
        <mesh filename="package://ar3_description/meshes/link_5.STL"/>
      </geometry>
      <material name="">
        <color rgba="1 1 0 1"/>
      </material>
    </visual>
    <collision>
      <origin rpy="0 0 0" xyz="0 0 0"/>
      <geometry>
        <mesh filename="package://ar3_description/meshes/link_5.STL"/>
      </geometry>
    </collision>
  </link>

  <joint name="joint_5" type="revolute">
    <origin rpy="${pi} 0 -2.8262" xyz="0 0 -0.22225"/>
    <parent link="link_4"/>
    <child link="link_5"/>
    <axis xyz="1 0 0"/>
    <limit lower="-1.81776042" upper="1.81776042" effort="100" velocity="100"/>
  </joint>

  <link name="link_6">
    <inertial>
      <origin rpy="0 0 0" xyz="2.9287E-10 -1.6472E-09 0.0091432"/>
      <mass value="0.013863"/>
      <inertia ixx="1.3596E-06" ixy="3.0585E-13" ixz="5.7102E-14" iyy="1.7157E-06" iyz="6.3369E-09" izz="2.4332E-06"/>
    </inertial>
    <visual>
      <origin rpy="0 0 0" xyz="0 0 0"/>
      <geometry>
        <mesh filename="package://ar3_description/meshes/link_6.STL"/>
      </geometry>
      <material name="">
        <color rgba="1 1 0 1"/>
      </material>
    </visual>
    <collision>
      <origin rpy="0 0 0" xyz="0 0 0"/>
      <geometry>
        <mesh filename="package://ar3_description/meshes/link_6.STL"/>
      </geometry>
    </collision>
  </link>

  <joint name="joint_6" type="revolute">
    <origin rpy="0 0 3.1416" xyz="-0.000294 0 0.02117"/>
    <parent link="link_5"/>
    <child link="link_6"/>
    <axis xyz="0 0 1"/>
    <limit lower="-2.5848326" upper="2.5848326" effort="100" velocity="100"/>
  </joint>

  <!-- add table -->
  <link name="table">
    <visual>
      <origin xyz="0 0 0" rpy="0 0 0" />
      <geometry >
				<box size="0.5 0.3 0.01" />
      </geometry>
        <material name="SwivelLightGray" /> 
    </visual> 
    <collision>
      <origin xyz="0 0 0" rpy="0 0 0" />
      <geometry >
				<box size="0.7 0.5 0.01" />
      </geometry>
    </collision>      
    <inertial>
      <mass value="9"/>
      <inertia ixx="9.0" ixy="0.0" ixz="0.0" iyy="9.0" iyz="0.0" izz="9.0"/>
    </inertial> 
  </link>

  <joint name="world_table" type="fixed">
    <parent link="world"/>
    <child link="table"/>
    <origin xyz="0 -0.4 0.25" rpy="0 0 0" />  
  </joint>
    
  <gazebo reference="table">
       <material>Gazebo/LightGray</material>
  </gazebo>

  <!-- add box1 -->
  <link name="box1">
    <visual>
      <origin xyz="0 0 0" rpy="0 0 0" />
      <geometry >
				<box size="0.05 0.05 0.08" />
      </geometry>
        <material name="SwivelRed" /> 
    </visual> 
    <collision>
      <origin xyz="0 0 0" rpy="0 0 0" />
      <geometry >
				<box size="0.05 0.05 0.08" />
      </geometry>
    </collision>      
    <inertial>
      <mass value="9"/>
      <inertia ixx="9.0" ixy="0.0" ixz="0.0" iyy="9.0" iyz="0.0" izz="9.0"/>
    </inertial> 
  </link>

  <joint name="table_box1" type="fixed">
    <parent link="table"/>
    <child link="box1"/>
    <origin xyz="0 0 0.04" rpy="0 0 0" />  
  </joint>
    
  <gazebo reference="box1">
       <material>Gazebo/Red</material>
  </gazebo>

  <!-- add box2 -->
  <link name="box2">
    <visual>
      <origin xyz="0 0 0" rpy="0 0 0" />
      <geometry >
				<box size="0.04 0.04 0.04" />
      </geometry>
        <material name="SwivelGreen" /> 
    </visual> 
    <collision>
      <origin xyz="0 0 0" rpy="0 0 0" />
      <geometry >
				<box size="0.04 0.04 0.04" />
      </geometry>
    </collision>      
    <inertial>
      <mass value="9"/>
      <inertia ixx="9.0" ixy="0.0" ixz="0.0" iyy="9.0" iyz="0.0" izz="9.0"/>
    </inertial> 
  </link>

  <joint name="table_box2" type="fixed">
    <parent link="table"/>
    <child link="box2"/>
    <origin xyz="0.1 0.05 0.025" rpy="0 0 0" />  
  </joint>
    
  <gazebo reference="box2">
       <material>Gazebo/Green</material>
  </gazebo>

  <!-- add cylinder1 -->
  <link name="cylinder1">
    <visual>
      <origin xyz="0 0 0" rpy="0 0 0" />
      <geometry >
				<cylinder length="0.02" radius="0.03"/>
      </geometry>
        <material name="SwivelGreen" /> 
    </visual> 
    <collision>
      <origin xyz="0 0 0" rpy="0 0 0" />
      <geometry >
				<cylinder length="0.02" radius="0.03"/>
      </geometry>
    </collision>      
    <inertial>
      <mass value="9"/>
      <inertia ixx="9.0" ixy="0.0" ixz="0.0" iyy="9.0" iyz="0.0" izz="9.0"/>
    </inertial> 
  </link>

  <joint name="table_cylinder1" type="fixed">
    <parent link="table"/>
    <child link="cylinder1"/>
    <origin xyz="-0.1 0.05 0.015" rpy="0 0 0" />  
  </joint>
    
  <gazebo reference="cylinder1">
       <material>Gazebo/Blue</material>
  </gazebo>

  <!-- add box3 -->
  <link name="box3">
    <visual>
      <origin xyz="0 0 0" rpy="0 0 0" />
      <geometry >
				<box size="0.02 0.02 0.02" />
      </geometry>
        <material name="SwivelRed" /> 
    </visual> 
    <collision>
      <origin xyz="0 0 0" rpy="0 0 0" />
      <geometry >
				<box size="0.02 0.02 0.02" />
      </geometry>
    </collision>      
    <inertial>
      <mass value="9"/>
      <inertia ixx="9.0" ixy="0.0" ixz="0.0" iyy="9.0" iyz="0.0" izz="9.0"/>
    </inertial> 
  </link>

  <joint name="world_box3" type="fixed">
    <parent link="world"/>
    <child link="box3"/>
    <origin xyz="0 -0.22 0.65" rpy="0 0 0" />  
  </joint>
    
  <gazebo reference="box3">
       <material>Gazebo/Red</material>
  </gazebo>


  <transmission name="transmission_1">
    <type>transmission_interface/SimpleTransmission</type>
    <joint name="joint_1">
        <hardwareInterface>hardware_interface/PositionJointInterface</hardwareInterface>
    </joint>
    <actuator name="motor_1">
        <hardwareInterface>hardware_interface/PositionJointInterface</hardwareInterface>
        <mechanicalReduction>1</mechanicalReduction>
    </actuator>
  </transmission>

  <transmission name="transmission_2">
      <type>transmission_interface/SimpleTransmission</type>
      <joint name="joint_2">
          <hardwareInterface>hardware_interface/PositionJointInterface</hardwareInterface>
      </joint>
      <actuator name="motor_2">
          <hardwareInterface>hardware_interface/PositionJointInterface</hardwareInterface>
          <mechanicalReduction>1</mechanicalReduction>
      </actuator>
  </transmission>

  <transmission name="transmission_3">
      <type>transmission_interface/SimpleTransmission</type>
      <joint name="joint_3">
          <hardwareInterface>hardware_interface/PositionJointInterface</hardwareInterface>
      </joint>
      <actuator name="motor_3">
          <hardwareInterface>hardware_interface/PositionJointInterface</hardwareInterface>
          <mechanicalReduction>1</mechanicalReduction>
      </actuator>
  </transmission>

  <transmission name="transmission_4">
      <type>transmission_interface/SimpleTransmission</type>
      <joint name="joint_4">
          <hardwareInterface>hardware_interface/PositionJointInterface</hardwareInterface>
      </joint>
      <actuator name="motor_4">
          <hardwareInterface>hardware_interface/PositionJointInterface</hardwareInterface>
          <mechanicalReduction>1</mechanicalReduction>
      </actuator>
  </transmission>

  <transmission name="transmission_5">
      <type>transmission_interface/SimpleTransmission</type>
      <joint name="joint_5">
          <hardwareInterface>hardware_interface/PositionJointInterface</hardwareInterface>
      </joint>
      <actuator name="motor_5">
          <hardwareInterface>hardware_interface/PositionJointInterface</hardwareInterface>
          <mechanicalReduction>1</mechanicalReduction>
      </actuator>
  </transmission>

  <transmission name="transmission_6">
      <type>transmission_interface/SimpleTransmission</type>
      <joint name="joint_6">
          <hardwareInterface>hardware_interface/PositionJointInterface</hardwareInterface>
      </joint>
      <actuator name="motor_6">
          <hardwareInterface>hardware_interface/PositionJointInterface</hardwareInterface>
          <mechanicalReduction>1</mechanicalReduction>
      </actuator>
  </transmission>  

  <gazebo>
    <plugin name="gazebo_ros_control" filename="libgazebo_ros_control.so">
    <controlPeriod>0.05</controlPeriod>
    <legacyModeNS>true</legacyModeNS>
    </plugin>
  </gazebo>
  <gazebo reference="base_link">
      <selfCollide>true</selfCollide>
  </gazebo>
  <gazebo reference="link_1">
      <selfCollide>true</selfCollide>
  </gazebo>
  <gazebo reference="link_2">
      <selfCollide>true</selfCollide>
  </gazebo>
  <gazebo reference="link_3">
      <selfCollide>true</selfCollide>
  </gazebo>
  <gazebo reference="link_4">
      <selfCollide>true</selfCollide>
  </gazebo>
  <gazebo reference="link_5">
      <selfCollide>true</selfCollide>
  </gazebo>
  <gazebo reference="link_6">
      <selfCollide>true</selfCollide>
  </gazebo>

<!--camera-->
    <!-- <link name="camera_link">
        <visual>
            <origin xyz=" 0 0 0 " rpy="${pi/2} 0 ${pi/2}" />
            <geometry>
                <mesh filename="package://ar3_description/meshes/realsense_d435.stl"/>
            </geometry>
            <material name="black">
                <color rgba="0 0 0 0.95"/>
            </material>
        </visual>
    </link>
 
    <joint name="camera_joint" type="fixed">
        <origin xyz="0 -0.35 0.7" rpy="${pi/2} ${pi/2} 0"/>
        <parent link="base_link"/>
        <child link="camera_link"/>
    </joint> -->
 
<!--gazebo-->
    <!-- <gazebo reference="camera_link"> 
            <sensor type="depth" name="camera">
            <update_rate>30.0</update_rate> 
            <camera name="head">
                <horizontal_fov>1.3962634</horizontal_fov> 
                <image>
                    <width>640</width> 
                    <height>480</height>
                    <format>R8G8B8</format> 
                </image>
                <clip>
                    <near>0.02</near> 
                    <far>300</far> 
                </clip>
            </camera>
            
            <plugin name="kinect_camera_controller" filename="libgazebo_ros_openni_kinect.so">
                <alwaysOn>true</alwaysOn>
                <updateRate>10</updateRate>
                <cameraName>camera</cameraName> 
                <imageTopicName>rgb/image_raw</imageTopicName>   
                
                <depthImageTopicName>depth/image_raw</depthImageTopicName>
		            <pointCloudTopicName>depth/points</pointCloudTopicName>
                <cameraInfoTopicName>rgb/camera_info</cameraInfoTopicName>
	            	<depthImageCameraInfoTopicName>depth/camera_info</depthImageCameraInfoTopicName>
                <frameName>camera_depth_optical_frame</frameName>
                <baseline>0.1</baseline>
                <distortion_k1>0.0</distortion_k1>
                <distortion_k2>0.0</distortion_k2>
                <distortion_k3>0.0</distortion_k3>
                <distortion_t1>0.0</distortion_t1>
                <distortion_t2>0.0</distortion_t2>
                <pointCloudCutoff>0.4</pointCloudCutoff>
            </plugin>
        </sensor>
    </gazebo> -->

</robot>

1.1 URDF文件解释

<xacro:include filename="$(find realsense_ros_gazebo)/xacro/tracker.xacro"/>
  <xacro:include filename="$(find realsense_ros_gazebo)/xacro/depthcam.xacro"/>
        
  <xacro:realsense_d435 sensor_name="d435" parent_link="base_link" rate="10">
    <origin rpy="${pi/2} ${pi/2} 0 " xyz="0 -0.35 0.7"/>
  </xacro:realsense_d435>

这一部分是引用realsense相机的urdf文件，加入到机械臂描述文件中。realsense相机描述文件在github上也可以下载。

<origin rpy="${pi/2} ${pi/2} 0 " xyz="0 -0.35 0.7"/>

这条语句描述的是相机的link相对于base_link的坐标变换，即坐标是（0，-0.35，0.7），姿态是先绕着相机自身坐标系的y轴按右手定则转90度，然后绕着新的坐标系的x轴转90度。

  <!-- add table -->
  <link name="table">
    <visual>
      <origin xyz="0 0 0" rpy="0 0 0" />
      <geometry >
				<box size="0.5 0.3 0.01" />
      </geometry>
        <material name="SwivelLightGray" /> 
    </visual> 
    <collision>
      <origin xyz="0 0 0" rpy="0 0 0" />
      <geometry >
				<box size="0.7 0.5 0.01" />
      </geometry>
    </collision>      
    <inertial>
      <mass value="9"/>
      <inertia ixx="9.0" ixy="0.0" ixz="0.0" iyy="9.0" iyz="0.0" izz="9.0"/>
    </inertial> 
  </link>

  <joint name="world_table" type="fixed">
    <parent link="world"/>
    <child link="table"/>
    <origin xyz="0 -0.4 0.25" rpy="0 0 0" />  
  </joint>
    
  <gazebo reference="table">
       <material>Gazebo/LightGray</material>
  </gazebo>

这一段的作用是在环境里添加桌子，主要包含 link , joint, gazebo说明三块，其中joint决定桌子的位置相对world的位置，我这里也可以写成base_link，因为我这里的world和base_link坐标系是完全重合的。可以调整桌子的高度和距离机械臂的距离，不能太近，太近会撞到机械臂。
box放在桌子上作为物体，还加了一个障碍物作为机械臂moveit规划的避障物体。

1.2 启动gazebo

执行 roslaunch ar3_gazebo ar3_gazebo_bringup.launch
启动gazebo仿真环境，出现下面场景：
在这里插入图片描述终端可能会报错：
这个不影响使用，可以不用管。

2、moveit配置

moveit官方教程：
https://moveit.picknik.ai/galactic/doc/tutorials/quickstart_in_rviz/quickstart_in_rviz_tutorial.html
安装moveit，可以使用moveit的配置助手

roslaunch moveit_setup_assistant setup_assistant.launch

官方教程也有给出。配置完成后，生成机械臂的moveit包。这里主要说一下规划组的运动学解算器的设置，在kinematic.yaml文件中：

manipulator:
  # kinematics_solver: kdl_kinematics_plugin/KDLKinematicsPlugin
  kinematics_solver: trac_ik_kinematics_plugin/TRAC_IKKinematicsPlugin
  kinematics_solver_search_resolution: 0.005
  kinematics_solver_timeout: 0.005

原本的解算器是kinematics_solver: kdl_kinematics_plugin/KDLKinematicsPlugin
改成了： kinematics_solver: trac_ik_kinematics_plugin/TRAC_IKKinematicsPlugin
有人说如果出现规划失败的问题：ABORTED: No motion plan found. No execution attempted.
就可以尝试换一下这个运动学插件。
如果换完之后编译出现缺少什么trac_ik包，安装即可。

修改默认的路径搜索算法

另外一点是在ompl_planning.yaml文件中，最后是

manipulator:
  default_planner_config: RRTkConfigDefault
  planner_configs:
    - SBLkConfigDefault
    - ESTkConfigDefault
    - LBKPIECEkConfigDefault
    - BKPIECEkConfigDefault
    - KPIECEkConfigDefault
    - RRTkConfigDefault
    - RRTConnectkConfigDefault
    - RRTstarkConfigDefault
    - TRRTkConfigDefault
    - PRMkConfigDefault
    - PRMstarkConfigDefault
    - FMTkConfigDefault
    - BFMTkConfigDefault
    - PDSTkConfigDefault
    - STRIDEkConfigDefault
    - BiTRRTkConfigDefault
    - LBTRRTkConfigDefault
    - BiESTkConfigDefault
    - ProjESTkConfigDefault
    - LazyPRMkConfigDefault
    - LazyPRMstarkConfigDefault
    - SPARSkConfigDefault
    - SPARStwokConfigDefault
  projection_evaluator: joints(joint_1,joint_2)
  longest_valid_segment_fraction: 0.005

其中，default_planner_config: RRTkConfigDefault是我后来添加的，可以删去，这里是设置默认的路径搜索算法（我个人理解），可以设置成其他的，从下面列出的之中选择。

3、启动moveit仿真环境

执行 roslaunch ar3_moveit_config ar3_moveit_bringup_demo.launch
这里我改了一下原有的启动文件，应该也可以直接使用原来的启动文件，我修改之后的ar3_moveit_bringup_demo.launch如下：

<launch>
    <!-- <rosparam command="load" file="$(find ar3_moveit_config)/config/joint_names.yaml" /> -->

    <include file="$(find ar3_moveit_config)/launch/planning_context.launch">
        <arg name="load_robot_description" value="false"/>
    </include>

    <node name="joint_state_publisher" pkg="joint_state_publisher" type="joint_state_publisher">
        <!-- <param name="/use_gui" value="true"/> -->
        <rosparam param="/source_list">[/joint_states]</rosparam>
    </node>
    
    <!-- Run the main MoveIt executable without trajectory execution (we do not have controllers configured by default) -->
    <include file="$(find ar3_moveit_config)/launch/move_group.launch">
        <arg name="allow_trajectory_execution" value="true"/>
        
    </include>

    <include file="$(find ar3_moveit_config)/launch/moveit_rviz.launch">
        <arg name="config" value="true"/>
    </include>

    <!-- World to base transform -->
    <node pkg="tf" type="static_transform_publisher" name="world_broadcaster" args = "0 0 0 0 0 0 world base_link 10" />

</launch>

启动moveit,并会打开rviz
在这里插入图片描述左下角是realense的rgb图像，右侧是机械臂+相机+桌子和物体+上方障碍物。

下面说一下坐标系的转换关系，这个对之后的物体坐标变换十分重要。
首先看一下world的frame和 base_link的frame,realsense的link的frame和table的frame，总共4个坐标系。
在这里插入图片描述左上角是相机link的frame，左下角是桌面的frame，右下角有world和base_link的frame，两个坐标系完全重合了。坐标系的颜色 R G B对应x y z轴。

然后是深度点云坐标系和world坐标系的关系
在这里插入图片描述可以发现深度点云坐标系的z轴是向下的，这里注意，之后相机发布的点云坐标，都是相对于这个
d435_depth_optical_frame的，都在这个坐标系下。因此从点云坐标，转换到base_link坐标系下，需要的过程是：

点云坐标  乘以  d435_depth_optical_frame相对于base_link的变换矩阵

这一点非常重要！！

4、利用深度相机获取目标点，并使用moveit规划路径

这一步是自己编写程序，订阅深度相机发布的点云话题，并声明一个moveit规划对象，设置目标的位置和姿态之后，使用moveit规划出路径并执行，然后gazebo中的机械臂就开始动了。
还是参考了官方文档：官方教程
官方使用了rviz自带的一个小界面，需要不断点next，我做了修改，代码如下

#include <moveit/move_group_interface/move_group_interface.h>
#include <moveit/planning_scene_interface/planning_scene_interface.h>
#include <moveit_msgs/DisplayRobotState.h>
#include <moveit_msgs/DisplayTrajectory.h>
#include <moveit_msgs/AttachedCollisionObject.h>
#include <moveit_msgs/CollisionObject.h>
#include <moveit_visual_tools/moveit_visual_tools.h>
#include <sensor_msgs/PointCloud.h>
#include <sensor_msgs/PointCloud2.h>
#include <sensor_msgs/point_cloud_conversion.h>
#include <ros/ros.h>
#include <iostream>
#include <Eigen/Core>
#include <Eigen/Geometry>

#define pi (3.1415926535897932346f)
using namespace std;

sensor_msgs::PointCloud out_pointcloud;
float x;
float y;
float z;
void pointCloud2ToZ(const sensor_msgs::PointCloud2 &msg)
{
	sensor_msgs::convertPointCloud2ToPointCloud(msg, out_pointcloud);
    // cout << "points_size = " << out_pointcloud.points.size() << endl;
  float z_min=10;
  for (int i=0; i<out_pointcloud.points.size(); i++) {
    if(out_pointcloud.points[i].y < 0.1){
          if(out_pointcloud.points[i].z < z_min){
          z_min = out_pointcloud.points[i].z;
      }
    }
  }
  float x_sum=0;
  float y_sum=0;
  float z_sum=0;
  int points_num = 20;
  int j = 0;
  for (int i=0; i<out_pointcloud.points.size(); i++){
    if(out_pointcloud.points[i].y < 0.1 and out_pointcloud.points[i].z < z_min + 0.01){
      if(j >= points_num){
        break;
      }
      x_sum = x_sum + out_pointcloud.points[i].x;
      y_sum = y_sum + out_pointcloud.points[i].y;
      z_sum = z_sum + out_pointcloud.points[i].z;
      j = j+1;
    }
  }
  x = x_sum / points_num;
  y = y_sum / points_num;
  z = z_min;
}
int main(int argc, char** argv)
{
  ros::init(argc, argv, "move2object");
  ros::NodeHandle node_handle;
  ros::AsyncSpinner spinner(1);
  spinner.start();
  ros::Subscriber sub = node_handle.subscribe("/d435/depth/color/points", 1, pointCloud2ToZ);
  // ros::Subscriber sub = node_handle.subscribe("/camera/depth/points", 1, pointCloud2ToZ);
  ros::Duration(1).sleep();
  ros::spinOnce();
  cout<<  "target in camera frame is  "<<"  x= " << x << "   y = " << y <<  "   z= " << z <<endl;

  Eigen::Isometry3d T=Eigen::Isometry3d::Identity();
  Eigen::AngleAxisd rotation_vector(-pi,Eigen::Vector3d(0,1,0));  //  ar3_gazebo.urdf.xacro

  //  ar3_gazebo_copy.xacro
  Eigen::AngleAxisd rotation_vector1;
  rotation_vector1 = Eigen::AngleAxisd(0, Eigen::Vector3d::UnitZ()) * 
                      Eigen::AngleAxisd(-pi, Eigen::Vector3d::UnitY()) * 
                      Eigen::AngleAxisd(0, Eigen::Vector3d::UnitX());  

  T.rotate(rotation_vector);
  T.pretranslate(Eigen::Vector3d(0, -0.35, 0.7));


  Eigen::Vector3d v(x,y,z);  
  Eigen::Vector3d v_transformed = T*v;

  Eigen::Vector3d ea(pi/2, 0, pi);
  Eigen::Quaterniond quaternion;
  quaternion = Eigen::AngleAxisd(ea[0], Eigen::Vector3d::UnitZ()) * Eigen::AngleAxisd(ea[1], Eigen::Vector3d::UnitY()) * Eigen::AngleAxisd(ea[2], Eigen::Vector3d::UnitX());
  
  cout <<"target_xyz in  world  frame is  " << "  x= " << v_transformed[0] << "   y = " <<   v_transformed[1]  <<  "   z= " <<   v_transformed[2] <<endl;
  static const std::string PLANNING_GROUP = "manipulator";
  // The :move_group_interface:`MoveGroupInterface` class can be easily
  // setup using just the name of the planning group you would like to control and plan for.
  moveit::planning_interface::MoveGroupInterface move_group(PLANNING_GROUP);
  // We will use the :planning_scene_interface:`PlanningSceneInterface`
  // class to add and remove collision objects in our "virtual world" scene
  moveit::planning_interface::PlanningSceneInterface planning_scene_interface;
  // Raw pointers are frequently used to refer to the planning group for improved performance.
  const robot_state::JointModelGroup* joint_model_group = move_group.getCurrentState()->getJointModelGroup(PLANNING_GROUP);
  // Getting Basic Information
  // We can print the name of the reference frame for this robot.
  ROS_INFO_NAMED("tutorial", "Planning frame: %s", move_group.getPlanningFrame().c_str());
  // We can also print the name of the end-effector link for this group.
  ROS_INFO_NAMED("tutorial", "End effector link: %s", move_group.getEndEffectorLink().c_str());
  geometry_msgs::Pose target_pose1;
  target_pose1.orientation.w = quaternion.w();
  target_pose1.orientation.x = quaternion.x();
  target_pose1.orientation.y = quaternion.y();
  target_pose1.orientation.z =  quaternion.z();
  target_pose1.position.x = v_transformed[0];
  target_pose1.position.y = v_transformed[1];
  target_pose1.position.z = v_transformed[2]+0.02;

  cout << "move to traget  pose1 is  " <<"  x= " << target_pose1.position.x<< "   y = " <<  target_pose1.position.y <<  "   z= " <<   target_pose1.position.z <<endl;
  move_group.setPoseTarget(target_pose1);

  // Now, we call the planner to compute the plan and visualize it.
  // Note that we are just planning, not asking move_group
  // to actually move the robot.
  moveit::planning_interface::MoveGroupInterface::Plan my_plan;

  bool success = (move_group.plan(my_plan) == moveit::planning_interface::MoveItErrorCode::SUCCESS);

  // ROS_INFO_NAMED("tutorial", "Visualizing plan 1 (pose goal) %s", success ? "" : "FAILED");
  // ROS_INFO_NAMED("tutorial", "Visualizing plan 1 as trajectory line");
  
  move_group.move();

  ros::shutdown();
  return 0;
}

这个代码做了如下事情：
1、订阅realsense发布的点云话题，获取点云坐标；
2、遍历所有点云，找到了桌面上处于最高位置的点；
3、找出了在最高位置的点附近的点，并求这些点的平均x坐标和y坐标，以此作为最终目标的x 和y，最终目标的z还是用的是最高位置点的z；
4、把目标的(x,y,z)坐标乘以 d435_depth_optical_frame相对于base_link的变换矩阵，得到目标在base_link下的坐标；
5、手动设置目标的姿态，姿态就让末端link_6朝下，直接通过rpy姿态角度转四元数；
6、把目标的姿态和位置复赋值给 geometry_msgs::Pose target_pose1;，这里我把z加了0。02m，如果不加，可能在后面的路径规划的时候，会报错，显示无法规划出一条可行路径，原因就是目标点与其他物体非常接近，或者就在其他物体内部，不管怎么规划，机械臂最终都会和其他物体发生碰撞，所以显示规划失败，解决方法是设置合理的目标点，避免根其他物体相碰撞；
7、使用moceit规划一条路径，并执行。

视频效果：

gazebo仿真动画

5.资源包链接

包含机械臂描述文件和moveit配置文件，以及机械臂运动仿真的一个demo

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