ros gazebo机械臂仿真，手动控制与MoveIt自动控制

本文总结归纳古月居胡春旭ros机械臂教程，给出了一些error的解决方法，补充了通过python运行moveit。十分建议去看github huchunxu源代码的repository。

创建机械臂的xacro模型

首先创建一个工作空间，在工作空间中创建arm_description功能包。功能包中创建一个urdf文件夹，放入机械臂模型文件arm.xacro

<?xml version="1.0"?>
<robot name="arm" xmlns:xacro="http://ros.org/wiki/xacro">

    <!-- Defining the colors used in this robot -->
    <material name="Black">
        <color rgba="0 0 0 1"/>
    </material>

    <material name="White">
        <color rgba="1 1 1 1"/>
    </material>

    <material name="Blue">
        <color rgba="0 0 1 1"/>
    </material>

    <material name="Red">
        <color rgba="1 0 0 1"/>
    </material>

    <!-- Constants -->
    <xacro:property name="M_PI" value="3.14159"/>

    <!-- link1 properties -->
    <xacro:property name="link1_width" value="0.03" />
    <xacro:property name="link1_len" value="0.10" />

    <!-- link2 properties -->
    <xacro:property name="link2_width" value="0.03" />
    <xacro:property name="link2_len" value="0.14" />

    <!-- link3 properties -->
    <xacro:property name="link3_width" value="0.03" />
    <xacro:property name="link3_len" value="0.22" />

    <!-- link4 properties -->
    <xacro:property name="link4_width" value="0.025" />
    <xacro:property name="link4_len" value="0.06" />

    <!-- link5 properties -->
    <xacro:property name="link5_width" value="0.03" />
    <xacro:property name="link5_len" value="0.06" />

    <!-- link6 properties -->
    <xacro:property name="link6_width" value="0.04" />
    <xacro:property name="link6_len" value="0.02" />

    <!-- Left gripper -->
    <xacro:property name="left_gripper_len" value="0.08" />
    <xacro:property name="left_gripper_width" value="0.01" />
    <xacro:property name="left_gripper_height" value="0.01" />

    <!-- Right gripper -->
    <xacro:property name="right_gripper_len" value="0.08" />
    <xacro:property name="right_gripper_width" value="0.01" />
    <xacro:property name="right_gripper_height" value="0.01" />

    <!-- Gripper frame -->
    <xacro:property name="grasp_frame_radius" value="0.001" />

    <!-- Inertial matrix -->
    <xacro:macro name="inertial_matrix" params="mass">
        <inertial>
            <mass value="${mass}" />
            <inertia ixx="1.0" ixy="0.0" ixz="0.0" iyy="0.5" iyz="0.0" izz="1.0" />
        </inertial>
    </xacro:macro>

    <!-- ///   bottom_joint   // -->
    <joint name="bottom_joint" type="fixed">
        <origin xyz="0 0 0" rpy="0 0 0" />
        <parent link="base_link"/>
        <child link="bottom_link"/>
    </joint>
    <link name="bottom_link">
        <visual>
              <origin xyz=" 0 0 -0.02"  rpy="0 0 0"/>
                  <geometry>
                       <box size="1 1 0.02" />
                  </geometry>
              <material name="Brown" />
        </visual>
        <collision>
            <origin xyz=" 0 0 -0.02"  rpy="0 0 0"/>
            <geometry>
                <box size="1 1 0.02" />
            </geometry>
        </collision>
        <xacro:inertial_matrix mass="500"/>
    </link>

    <!-- /   BASE LINK    // -->
    <link name="base_link">
        <visual>
            <origin xyz="0 0 0" rpy="0 0 0" />
            <geometry>
                <box size="0.1 0.1 0.04" />
            </geometry>
            <material name="White" />
        </visual>
        <collision>
            <origin xyz="0 0 0" rpy="0 0 0" />
            <geometry>
                <box size="0.1 0.1 0.04" />
            </geometry>
        </collision>
        <xacro:inertial_matrix mass="1"/>
    </link>

    <joint name="joint1" type="revolute">
        <parent link="base_link"/>
        <child link="link1"/>
        <origin xyz="0 0 0.02" rpy="0 ${M_PI/2} 0" />
        <axis xyz="-1 0 0" />
        <limit effort="300" velocity="1" lower="-2.96" upper="2.96"/>
        <dynamics damping="50" friction="1"/>
    </joint>

    <!-- /   LINK1  // -->
    <link name="link1" >
        <visual>
            <origin xyz="-${link1_len/2} 0 0" rpy="0 ${M_PI/2} 0" />
            <geometry>
                <cylinder radius="${link1_width}" length="${link1_len}"/>
            </geometry>
            <material name="Blue" />
        </visual>
        <collision>
            <origin xyz="-${link1_len/2} 0 0" rpy="0 ${M_PI/2} 0" />
            <geometry>
                <cylinder radius="${link1_width}" length="${link1_len}"/>
            </geometry>
        </collision>
        <xacro:inertial_matrix mass="1"/>
    </link>

    <joint name="joint2" type="revolute">
        <parent link="link1"/>
        <child link="link2"/>
        <origin xyz="-${link1_len} 0 0.0" rpy="-${M_PI/2} 0 ${M_PI/2}" />
        <axis xyz="1 0 0" />
        <limit effort="300" velocity="1" lower="-2.35" upper="2.35" />
        <dynamics damping="50" friction="1"/>
    </joint>

    <!-- ///   LINK2  // -->
    <link name="link2" >
        <visual>
            <origin xyz="0 0 ${link2_len/2}" rpy="0 0 0" />
            <geometry>
                <cylinder radius="${link2_width}" length="${link2_len}"/>
            </geometry>
            <material name="White" />
        </visual>

        <collision>
            <origin xyz="0 0 ${link2_len/2}" rpy="0 0 0" />
            <geometry>
                <cylinder radius="${link2_width}" length="${link2_len}"/>
            </geometry>
        </collision>
        <xacro:inertial_matrix mass="1"/>
    </link>

    <joint name="joint3" type="revolute">
        <parent link="link2"/>
        <child link="link3"/>
        <origin xyz="0 0 ${link2_len}" rpy="0 ${M_PI} 0" />
        <axis xyz="-1 0 0" />
        <limit effort="300" velocity="1" lower="-2.62" upper="2.62" />
        <dynamics damping="50" friction="1"/>
    </joint>

    <!-- /   LINK3  / -->
    <link name="link3" >
        <visual>
            <origin xyz="0 0 -${link3_len/2}" rpy="0 0 0" />
            <geometry>
                <cylinder radius="${link3_width}" length="${link3_len}"/>
            </geometry>
            <material name="Blue" />
        </visual>
        <collision>
            <origin xyz="0 0 -${link3_len/2}" rpy="0 0 0" />
            <geometry>
                <cylinder radius="${link3_width}" length="${link3_len}"/>
            </geometry>
        </collision>
        <xacro:inertial_matrix mass="1"/>
    </link>

    <joint name="joint4" type="revolute">
        <parent link="link3"/>
        <child link="link4"/>
        <origin xyz="0.0 0.0 -${link3_len}" rpy="0 ${M_PI/2} ${M_PI}" />
        <axis xyz="1 0 0" />
        <limit effort="300" velocity="1" lower="-2.62" upper="2.62" />
        <dynamics damping="50" friction="1"/>
    </joint>

    <!-- ///   LINK4   -->
    <link name="link4" >
        <visual>
            <origin xyz="${link4_len/2} 0 0" rpy="0 ${M_PI/2} 0" />
            <geometry>
                <cylinder radius="${link4_width}" length="${link4_len}"/>
            </geometry>
            <material name="Black" />
        </visual>
        <collision>
            <origin xyz="${link4_len/2} 0 0" rpy="0 ${M_PI/2} 0" />
            <geometry>
                <cylinder radius="${link4_width}" length="${link4_len}"/>
            </geometry>
        </collision>
        <xacro:inertial_matrix mass="1"/>
    </link>

    <joint name="joint5" type="revolute">
        <parent link="link4"/>
        <child link="link5"/>
        <origin xyz="${link4_len} 0.0 0.0" rpy="0 ${M_PI/2} 0" />
        <axis xyz="1 0 0" />
        <limit effort="300" velocity="1" lower="-2.62" upper="2.62" />
        <dynamics damping="50" friction="1"/>
    </joint>

    <!-- //   LINK5  / -->
    <link name="link5">
        <visual>
            <origin xyz="0 0 ${link4_len/2}" rpy="0 0 0" />
            <geometry>
                <cylinder radius="${link5_width}" length="${link5_len}"/>
            </geometry>
            <material name="White" />
        </visual>
        <collision>
            <origin xyz="0 0 ${link4_len/2} " rpy="0 0 0" />
            <geometry>
                <cylinder radius="${link5_width}" length="${link5_len}"/>
            </geometry>
        </collision>
        <xacro:inertial_matrix mass="1"/>
    </link>

    <joint name="joint6" type="revolute">
        <parent link="link5"/>
        <child link="link6"/>
        <origin xyz="0 0 ${link4_len}" rpy="${1.5*M_PI} -${M_PI/2} 0" />
        <axis xyz="1 0 0" />
        <limit effort="300" velocity="1" lower="-6.28" upper="6.28" />
        <dynamics damping="50" friction="1"/>
    </joint>

    <!--    LINK6  / -->
    <link name="link6">
        <visual>
            <origin xyz="${link6_len/2} 0 0 " rpy="0 ${M_PI/2} 0" />
            <geometry>
                <cylinder radius="${link6_width}" length="${link6_len}"/>
            </geometry>
            <material name="Blue" />
        </visual>
        <collision>
            <origin xyz="${link6_len/2} 0 0" rpy="0 ${M_PI/2} 0" />
            <geometry>
                <cylinder radius="${link6_width}" length="${link6_len}"/>
            </geometry>
        </collision>
        <xacro:inertial_matrix mass="1"/>
    </link>

    <joint name="finger_joint1" type="prismatic">
        <parent link="link6"/>
        <child link="gripper_finger_link1"/>
        <origin xyz="0.0 0 0" />
        <axis xyz="0 1 0" />
        <limit effort="100" lower="0" upper="0.06" velocity="1.0"/>
        <dynamics damping="50" friction="1"/>
    </joint>

    <!-- //   gripper   // -->
    <!-- LEFT GRIPPER AFT LINK -->
    <link name="gripper_finger_link1">
        <visual>
            <origin xyz="0.04 -0.03 0"/>
            <geometry>
                <box size="${left_gripper_len} ${left_gripper_width} ${left_gripper_height}" />
            </geometry>
            <material name="White" />
        </visual>
        <xacro:inertial_matrix mass="1"/>
    </link>

    <joint name="finger_joint2" type="fixed">
        <parent link="link6"/>
        <child link="gripper_finger_link2"/>
        <origin xyz="0.0 0 0" />
    </joint>

    <!-- RIGHT GRIPPER AFT LINK -->
    <link name="gripper_finger_link2">
        <visual>
            <origin xyz="0.04 0.03 0"/>
            <geometry>
                <box size="${right_gripper_len} ${right_gripper_width} ${right_gripper_height}" />
            </geometry>
            <material name="White" />
        </visual>
        <xacro:inertial_matrix mass="1"/>
    </link>

    <!-- Grasping frame -->
    <link name="grasping_frame"/>

    <joint name="grasping_frame_joint" type="fixed">
      <parent link="link6"/>
      <child link="grasping_frame"/>
      <origin xyz="0.08 0 0" rpy="0 0 0"/>
    </joint>

    <!-- /   Gazebo   // -->
    <gazebo reference="bottom_link">
        <material>Gazebo/White</material>
    </gazebo>
    <gazebo reference="base_link">
        <material>Gazebo/White</material>
    </gazebo>
    <gazebo reference="link1">
        <material>Gazebo/Blue</material>
    </gazebo>
    <gazebo reference="link2">
        <material>Gazebo/White</material>
    </gazebo>
    <gazebo reference="link3">
        <material>Gazebo/Blue</material>
    </gazebo>
    <gazebo reference="link4">
        <material>Gazebo/Black</material>
    </gazebo>
    <gazebo reference="link5">
        <material>Gazebo/White</material>
    </gazebo>
    <gazebo reference="link6">
        <material>Gazebo/Blue</material>
    </gazebo>
    <gazebo reference="gripper_finger_link1">
        <material>Gazebo/White</material>
    </gazebo>
    <gazebo reference="gripper_finger_link2">
        <material>Gazebo/White</material>
    </gazebo>
    
    <!-- Transmissions for ROS Control -->
    <xacro:macro name="transmission_block" params="joint_name">
        <transmission name="tran1">
            <type>transmission_interface/SimpleTransmission</type>
            <joint name="${joint_name}">
                <hardwareInterface>hardware_interface/PositionJointInterface</hardwareInterface>
            </joint>
            <actuator name="motor1">
                <hardwareInterface>hardware_interface/PositionJointInterface</hardwareInterface>
                <mechanicalReduction>1</mechanicalReduction>
            </actuator>
        </transmission>
    </xacro:macro>
    
    <xacro:transmission_block joint_name="joint1"/>
    <xacro:transmission_block joint_name="joint2"/>
    <xacro:transmission_block joint_name="joint3"/>
    <xacro:transmission_block joint_name="joint4"/>
    <xacro:transmission_block joint_name="joint5"/>
    <xacro:transmission_block joint_name="joint6"/>
    <xacro:transmission_block joint_name="finger_joint1"/>

    <!-- ros_control plugin -->
    <gazebo>
        <plugin name="gazebo_ros_control" filename="libgazebo_ros_control.so">
            <robotNamespace>/arm</robotNamespace>
        </plugin>
    </gazebo>

</robot>

Transmission for ROS Control那一部分相当于是给关节绑定上电机，通过控制电机控制关节运动。

再创建一个launch文件夹，创建view_arm.launch文件

<launch>
    <arg name="model" />
    <!-- 加载机器人模型参数 -->
    <param name="robot_description" command="$(find xacro)/xacro --inorder $(find arm_description)/urdf/arm.xacro" />

    <!-- 设置GUI参数，显示关节控制插件 -->
    <!-- <param name="use_gui" value="true"/> -->

    <!-- 运行joint_state_publisher节点，发布机器人的关节状态  -->
    <node name="joint_state_publisher" pkg="joint_state_publisher" type="joint_state_publisher" />
    
    <!-- 运行robot_state_publisher节点，发布tf  -->
    <node name="robot_state_publisher" pkg="robot_state_publisher" type="state_publisher" />

    <!-- 运行rviz可视化界面 -->
    <node name="rviz" pkg="rviz" type="rviz"/>
</launch>

运行这个launch文件，在rviz中选择fixed frame，再加载Robot Model，就可以看见机械臂了。

在Gazebo中手动控制机械臂

在工作空间中再创建一个arm_gazebo功能包，添加launch文件夹，创建arm_world.launch

<launch>

  <!-- these are the arguments you can pass this launch file, for example paused:=true -->
  <arg name="paused" default="false"/>
  <arg name="use_sim_time" default="true"/>
  <arg name="gui" default="true"/>
  <arg name="headless" default="false"/>
  <arg name="debug" default="false"/>

  <!-- We resume the logic in empty_world.launch -->
  <include file="$(find gazebo_ros)/launch/empty_world.launch">
    <arg name="debug" value="$(arg debug)" />
    <arg name="gui" value="$(arg gui)" />
    <arg name="paused" value="$(arg paused)"/>
    <arg name="use_sim_time" value="$(arg use_sim_time)"/>
    <arg name="headless" value="$(arg headless)"/>
  </include>

  <!-- Load the URDF into the ROS Parameter Server -->
  <param name="robot_description" command="$(find xacro)/xacro --inorder '$(find arm_description)/urdf/arm.xacro'" /> 


  <!-- Run a python script to the send a service call to gazebo_ros to spawn a URDF robot -->
  <node name="urdf_spawner" pkg="gazebo_ros" type="spawn_model" respawn="false" output="screen"
	args="-urdf -model arm -param robot_description"/> 


</launch>

功能是：创建一个环境，并且将机器人模型放进去。

下面要做的是加载控制器，首先要设定pid控制器的参数。在arm_gazebo功能包中创建config文件夹，创建arm_gazebo_control.yaml，给6个关节设定pid控制器参数。

arm:
  # Publish all joint states -----------------------------------
  joint_state_controller:
    type: joint_state_controller/JointStateController
    publish_rate: 50  
  
  # Position Controllers ---------------------------------------
  joint1_position_controller:
    type: position_controllers/JointPositionController
    joint: joint1
    pid: {p: 100.0, i: 0.01, d: 10.0}
  joint2_position_controller:
    type: position_controllers/JointPositionController
    joint: joint2
    pid: {p: 100.0, i: 0.01, d: 10.0}
  joint3_position_controller:
    type: position_controllers/JointPositionController
    joint: joint3
    pid: {p: 100.0, i: 0.01, d: 10.0}
  joint4_position_controller:
    type: position_controllers/JointPositionController
    joint: joint4
    pid: {p: 100.0, i: 0.01, d: 10.0}
  joint5_position_controller:
    type: position_controllers/JointPositionController
    joint: joint5
    pid: {p: 100.0, i: 0.01, d: 10.0}
  joint6_position_controller:
    type: position_controllers/JointPositionController
    joint: joint6
    pid: {p: 100.0, i: 0.01, d: 10.0}
 

在launch文件夹中创建arm_gazebo_controller.launch，实现的作用是加载刚才创建的pid参数yaml文件，创建控制器。

<launch>

    <!-- 将关节控制器的配置参数加载到参数服务器中 -->
    <rosparam file="$(find arm_gazebo)/config/arm_gazebo_control.yaml" command="load"/>

    <!-- 加载controllers -->
    <node name="controller_spawner" pkg="controller_manager" type="spawner" respawn="false"
          output="screen" ns="/arm" args="joint_state_controller
                                          joint1_position_controller
                                          joint2_position_controller
                                          joint3_position_controller
                                          joint4_position_controller
                                          joint5_position_controller
                                          joint6_position_controller"/>

    <!-- 运行robot_state_publisher节点，发布tf  -->
    <node name="robot_state_publisher" pkg="robot_state_publisher" type="robot_state_publisher"
          respawn="false" output="screen">
        <remap from="/joint_states" to="/arm/joint_states" />
    </node>

</launch>

最后再创建一个arm_gazebo_control.launch文件，其作用是，运行world launch和controller launch两个launch文件。

<launch>

    <!-- 启动Gazebo  -->
    <include file="$(find arm_gazebo)/launch/arm_world.launch" />   

    <!-- 启动Gazebo controllers -->
    <include file="$(find arm_gazebo)/launch/arm_gazebo_controller.launch" />   

</launch>

运行arm_gazebo_control.launch文件，再另外打开两个terminal，分别运行

rqt

rosrun rviz rviz

通过rqt发送指令，可以在gazebo和rviz中同时看到机械臂的动作。

配置MoveIt

rosrun?moveit_setup_assistant?moveit_setup_assistant

依次加载模型，生成碰撞矩阵，生成规划组，如下图所示，一个arm规划组和一个gripper规划组，注意“3”那里，新版本的moveit那里不一样，空着就好。

?

?

?添加一个初始位姿，命名为home

?配置终端夹爪

最后再添加作者信息，生成配置文件就可以了。命名为arm_moveit_config，和前面创建的两个功能包arm_description, arm_gazebo并列放在一起。

用moveIt控制gazebo中的机械臂

在arm_gazebo功能包中创建关节轨迹控制器，一个控制器包含两个部分：yaml配置文件和launch运行文件，yaml配置文件放在功能包的config文件夹中，里面写着控制器的参数，运行文件放在launch文件夹中，用于运行控制器。

在arm_moveit_config功能包中创建一个gazebo控制器，同样是一组.yaml和.launch文件（注意这个launch文件的后缀是.launch.xml，这个文件自动存在，不需要创建，我们要改内容），launch文件加载yaml文件，分别放在config文件夹和launch文件夹。以及另外一个单独的.launch（moveit_planning_execution.launch）。

moveit功能包中的控制器和gazebo功能包中的控制器的关系是：通过ros的Action机制，moveit功能包中的控制器发布关节轨迹点指令，gazebo功能包中的控制器控制关节电机是关节到达轨迹点。

还要在arm_gazebo功能包中创建一个关节状态控制器，用于发布关节状态和tf变换。这个是为了在rviz中可视化用。

总结：一共三个控制器7个文件（3个.yaml和4个.launch）

arm_gazebo功能包中的命名为：trajectory_control.yaml??? arm_trajectory_controller.launch

arm_gazebo_joint_states.yaml????? arm_gazebo_states.launch

arm_moveit_config功能包中的命名为：controllers_gazebo.yaml??? arm_moveit_controller_manager.launch.xml

moveit_planning_execution.launch

以上文件的内容整理在后文。最后再创建一个.launch，其作用是一次性运行上面的所有.launch。命名为arm_bringup_moveit.launch，放在arm_gazebo功能包的launch文件夹。

运行最后写的那个.launch，就可以通过rviz中的moveit插件来控制gazebo中的机械臂了。

roslaunch?marm_gazebo?arm_bringup_moveit.launch

?trajectory_control.yaml 内容：

arm:
  arm_joint_controller:
    type: "position_controllers/JointTrajectoryController"
    joints:
      - joint1
      - joint2
      - joint3
      - joint4
      - joint5
      - joint6

    gains:
      joint1:   {p: 1000.0, i: 0.0, d: 0.1, i_clamp: 0.0}
      joint2:   {p: 1000.0, i: 0.0, d: 0.1, i_clamp: 0.0}
      joint3:   {p: 1000.0, i: 0.0, d: 0.1, i_clamp: 0.0}
      joint4:   {p: 1000.0, i: 0.0, d: 0.1, i_clamp: 0.0}
      joint5:   {p: 1000.0, i: 0.0, d: 0.1, i_clamp: 0.0}
      joint6:   {p: 1000.0, i: 0.0, d: 0.1, i_clamp: 0.0}


  gripper_controller:
    type: "position_controllers/JointTrajectoryController"
    joints:
      - finger_joint1
    gains:
      finger_joint1:  {p: 50.0, d: 1.0, i: 0.01, i_clamp: 1.0}

?arm_trajectory_controller.launch 内容：

<launch>

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

    <node name="arm_controller_spawner" pkg="controller_manager" type="spawner" respawn="false"
          output="screen" ns="/arm" args="arm_joint_controller gripper_controller"/>

</launch>

arm_gazebo_joint_states.yaml 内容：

arm:
  # Publish all joint states -----------------------------------
  joint_state_controller:
    type: joint_state_controller/JointStateController
    publish_rate: 50  
  

arm_gazebo_states.launch 内容：

<launch>
    <!-- 将关节控制器的配置参数加载到参数服务器中 -->
    <rosparam file="$(find arm_gazebo)/config/arm_gazebo_joint_states.yaml" command="load"/>

    <node name="joint_controller_spawner" pkg="controller_manager" type="spawner" respawn="false"
          output="screen" ns="/arm" args="joint_state_controller" />

    <!-- 运行robot_state_publisher节点，发布tf  -->
    <node name="robot_state_publisher" pkg="robot_state_publisher" type="robot_state_publisher"
        respawn="false" output="screen">
        <remap from="/joint_states" to="/arm/joint_states" />
    </node>

</launch>

controllers_gazebo.yaml内容：

controller_manager_ns: controller_manager
controller_list:
  - name: arm/arm_joint_controller
    action_ns: follow_joint_trajectory
    type: FollowJointTrajectory
    default: true
    joints:
      - joint1
      - joint2
      - joint3
      - joint4
      - joint5
      - joint6

  - name: arm/gripper_controller
    action_ns: follow_joint_trajectory
    type: FollowJointTrajectory
    default: true
    joints:
      - finger_joint1
      - finger_joint2

arm_moveit_controller_manager.launch.xml内容：

<launch>
  <!-- Set the param that trajectory_execution_manager needs to find the controller plugin -->
  <arg name="moveit_controller_manager" default="moveit_simple_controller_manager/MoveItSimpleControllerManager" />
  <param name="moveit_controller_manager" value="$(arg moveit_controller_manager)"/>

  <!-- load controller_list -->
  <!-- Arbotix -->
  <!-- <rosparam file="$(find marm_moveit_config)/config/controllers.yaml"/> -->
  <!-- Gazebo -->
  <rosparam file="$(find arm_moveit_config)/config/controllers_gazebo.yaml"/>
</launch>

moveit_planning_execution.launch内容：

<launch>
 # The planning and execution components of MoveIt! configured to 
 # publish the current configuration of the robot (simulated or real)
 # and the current state of the world as seen by the planner
 <include file="$(find arm_moveit_config)/launch/move_group.launch">
  <arg name="publish_monitored_planning_scene" value="true" />
 </include>
 # The visualization component of MoveIt!
 <include file="$(find arm_moveit_config)/launch/moveit_rviz.launch"/>

  <!-- We do not have a robot connected, so publish fake joint states -->
  <node name="joint_state_publisher" pkg="joint_state_publisher" type="joint_state_publisher">
    <param name="/use_gui" value="false"/> 
    <rosparam param="/source_list">[/arm/joint_states]</rosparam>
  </node>

</launch>

arm_bringup_moveit.launch内容：

<launch>
  
    <!-- Launch Gazebo  -->
    <include file="$(find arm_gazebo)/launch/arm_world.launch" />

    <!-- ros_control arm launch file -->
    <include file="$(find arm_gazebo)/launch/arm_gazebo_states.launch" />   

    <!-- ros_control trajectory control dof arm launch file -->
    <include file="$(find arm_gazebo)/launch/arm_trajectory_controller.launch" />

    <!-- moveit launch file -->
    <include file="$(find arm_moveit_config)/launch/moveit_planning_execution.launch" />

</launch>

一些可能出现的报错：

Tried to advertise on topic but the topic is already advertised

解决办法：

arm_moveit_config功能包中，sensors_3d.yaml文件中，出现了重名topic，修改第二个topic的名称

?Unable to identify any set of controllers that can actuate the specified joints:

解决办法：修改

工作空间/src/marm_moveit_config/launch/trajectory_execution.launch.xml

删掉?pass_all_args="true"

通过python的接口运行moveit

上面是通过rviz中的插件来控制moveit，下面通过py文件来运行moveit，不需要在rviz中操作moveit插件。

还是先运行arm_bringup_moveit.launch

再运行这个py文件，group_name是在moveit_setup_assistant中配置的group，在joint_goal那里设定关节目标角度 弧度制。

import sys
import rospy
import moveit_commander
from moveit_commander import PlanningSceneInterface


moveit_commander.roscpp_initialize(sys.argv)
rospy.init_node('move_group_python_interface_tutorial', anonymous=True)

## Instantiate a `RobotCommander`_ object. Provides information such as the robot's
## kinematic model and the robot's current joint states
robot = moveit_commander.RobotCommander()

## Instantiate a `PlanningSceneInterface`_ object.  This provides a remote interface
## for getting, setting, and updating the robot's internal understanding of the
## surrounding world:
scene = moveit_commander.PlanningSceneInterface()

## Instantiate a `MoveGroupCommander`_ object.  This object is an interface
## to a planning group (group of joints).  In this tutorial the group is the primary
## arm joints in the Panda robot, so we set the group's name to "panda_arm".
## If you are using a different robot, change this value to the name of your robot
## arm planning group.
## This interface can be used to plan and execute motions:
group_name = "arm"
move_group = moveit_commander.MoveGroupCommander(group_name)
joint_goal = move_group.get_current_joint_values()
print(joint_goal)
joint_goal[0] = 0
joint_goal[1] = 0.9
joint_goal[2] = 0
joint_goal[3] = 0


# The go command can be called with joint values, poses, or without any
# parameters if you have already set the pose or joint target for the group
move_group.go(joint_goal, wait=True)

# Calling ``stop()`` ensures that there is no residual movement
move_group.stop()

## END_SUB_TUTORIAL

# For testing:
current_joints = move_group.get_current_joint_values()
print(current_joints)

如果是pycharm运行py文件，注意interpreter选择，我的虚拟机安装的是ubuntu18 和ros melodic，需要python2.7的interpreter，另外还要把melodic的python包放进pycharm的project structure。另外，在pycharm中添加两个环境变量。以上。