Ubuntu16.04 ROS Kinetic - rviz_xycar 패키지 : RVIZ기반 자동차 바퀴 굴러가는 예제. move_joint.py

1. 과제

RVIZ에서 자동차를 3D 형상으로 모델링하고,

핸들 조작, 바퀴를 굴릴 수 있도록 제작하는 예제.

 

2. rviz_xycar 패키지

catkin_create_pkg rviz_xycar rospy tf geometry_msgs urdf rviz xacro

 

3. xycar_motor 토픽

2021/01/15 - [ROS] - Ubuntu16.04 ROS Kinetic - xycar_motor 패키지

Ubuntu16.04 ROS Kinetic - xycar_motor 패키지

 

4. launch 파일

launch폴더 만들고 xycar_3d.launch 작성.

<launch>
	<param name="robot_description" textfile="$(find rviz_xycar)/urdf/xycar_3d.urdf"/>
	<param name="use_gui" value="true"/>
	
	<!-- rviz display -->
	<node name="rviz_visualizer" pkg="rviz" type="rviz" required="true" args="-d $(find rviz_xycar)/rviz/xycar_3d.rviz"/>
	
	<!-- <node name="joint_state_publisher" pkg="joint_state_publisher" type="joint_state_publisher"/> -->
	<node name="move_joint" pkg="rviz_xycar" type="move_joint.py"/>
	<node name="robot_state_publisher" pkg="robot_state_publisher" type="state_publisher"/>
</launch>

 

5. 소스 파일

move_joint.py 작성하고 실행권한 부여

#!/usr/bin/env python

import rospy
from sensor_msgs.msg import JointState
from std_msgs.msg import Header

def talker():
    pub = rospy.Publisher('joint_states', JointState, queue_size=10)
    rospy.init_node('move_joint')
    rate = rospy.Rate(50) 

    hello_xycar = JointState()
    hello_xycar.header = Header()
    hello_xycar.name = ['front_right_hinge_joint', 'front_left_hinge_joint', 
                      'front_right_wheel_joint', 'front_left_wheel_joint',
                       'rear_right_wheel_joint','rear_left_wheel_joint']
    hello_xycar.velocity = []
    hello_xycar.effort = [] 
  
    a = -3.14
    b = -3.14

    while not rospy.is_shutdown():
      hello_xycar.header.stamp = rospy.Time.now()
      
      if a >= 3.14:
         a = -3.14
         b = -3.14
      else:
         a += 0.01
         b += 0.01

      hello_xycar.position = [0, 0, a, b, 0, 0]

      pub.publish(hello_xycar)
      rate.sleep()

if __name__ == '__main__':
    try:
        talker()
    except rospy.ROSInterruptException:
        pass

 

6. urdf 파일

urdf 폴더를 생성하여 xycar_3d.urdf 를 작성한다.

<?xml version="1.0" ?>
<robot name="xycar" xmlns:xacro="http://www.ros.org/wiki/xacro">
 <link name="base_link"/>
  <link name="baseplate">
    <visual>
      <material name="acrylic"/>
      <origin rpy="0 0 0" xyz="0 0 0"/>
      <geometry>
        <box size="0.5 0.2 0.07"/>
      </geometry>
    </visual>
  </link>
  <joint name="base_link_to_baseplate" type="fixed">
    <parent link="base_link"/>
    <child link="baseplate"/>
    <origin rpy="0 0 0" xyz="0 0 0"/>
  </joint>
  <link name="front_mount">
    <visual>
      <material name="blue"/>
      <origin rpy="0 0.0 0" xyz="-0.105 0 0"/>
      <geometry>
        <box size="0.50 0.12 0.01"/>
      </geometry>
    </visual>
  </link>
  <joint name="baseplate_to_front_mount" type="fixed">
    <parent link="baseplate"/>
    <child link="front_mount"/>
    <origin rpy="0 0 0" xyz="0.105 0 -0.059"/>
  </joint>

  <link name="front_shaft">
    <visual>
      <material name="black"/>
      <origin rpy="1.57 0 0" xyz="0 0 0"/>
      <geometry>
        <cylinder length="0.285" radius="0.018"/>
      </geometry>
    </visual>
  </link>
  <joint name="front_mount_to_front_shaft" type="fixed">
    <parent link="front_mount"/>
    <child link="front_shaft"/>
    <origin rpy="0 0 0" xyz="0.105 0 -0.059"/>
  </joint>
  <link name="rear_shaft">
    <visual>
      <material name="black"/>
      <origin rpy="1.57 0 0" xyz="0 0 0"/>
      <geometry>
        <cylinder length="0.285" radius="0.018"/>
      </geometry>
    </visual>
  </link>
  <joint name="rear_mount_to_rear_shaft" type="fixed">
    <parent link="front_mount"/>
    <child link="rear_shaft"/>
    <origin rpy="0 0 0" xyz="-0.305 0 -0.059"/>
  </joint>
  <link name="front_right_hinge">
    <visual>
      <material name="white"/>
      <origin rpy="0 0 0" xyz="0 0 0"/>
      <geometry>
        <sphere radius="0.015"/>
      </geometry>
    </visual>
  </link>
  <joint name="front_right_hinge_joint" type="revolute">
    <parent link="front_shaft"/>
    <child link="front_right_hinge"/>
    <origin rpy="0 0 0" xyz="0 -0.1425 0"/>
    <axis xyz="0 0 1"/>
    <limit effort="10" lower="-0.34" 
                       upper="0.34" velocity="100"/>
  </joint>
  <link name="front_left_hinge">
    <visual>
      <material name="white"/>
      <origin rpy="0 0 0" xyz="0 0 0"/>
      <geometry>
        <sphere radius="0.015"/>
      </geometry>
    </visual>
  </link>
  <joint name="front_left_hinge_joint" type="revolute">
    <parent link="front_shaft"/>
    <child link="front_left_hinge"/>
    <origin rpy="0 0 0" xyz="0 0.1425 0"/>
    <axis xyz="0 0 1"/>
    <limit effort="10" lower="-0.34" upper="0.34" velocity="100"/>
  </joint>
  <link name="front_right_wheel">
    <visual>
      <material name="black"/>
      <origin rpy="1.57 0 0" xyz="0 0 0"/>
      <geometry>
        <cylinder length="0.064" radius="0.07"/>
      </geometry>
    </visual>
  </link>
  <joint name="front_right_wheel_joint" type="continuous">
    <parent link="front_right_hinge"/>
    <child link="front_right_wheel"/>
    <origin rpy="0 0 0" xyz="0 0 0"/>
    <axis xyz="0 1 0"/>
    <limit effort="10" velocity="100"/>
  </joint>
  <link name="front_left_wheel">
    <visual>
      <material name="black"/>
      <origin rpy="1.57 0 0" xyz="0 0 0"/>
      <geometry>
        <cylinder length="0.064" radius="0.07"/>
      </geometry>
    </visual>
  </link>
  <joint name="front_left_wheel_joint" type="continuous">
    <parent link="front_left_hinge"/>
    <child link="front_left_wheel"/>
    <origin rpy="0 0 0" xyz="0 0 0"/>
    <axis xyz="0 1 0"/>
    <limit effort="10" velocity="100"/>
  </joint>
  <link name="rear_right_wheel">
    <visual>
      <material name="black"/>
      <origin rpy="1.57 0 0" xyz="0 0 0"/>
      <geometry>
        <cylinder length="0.064" radius="0.07"/>
      </geometry>
    </visual>
  </link>
  <joint name="rear_right_wheel_joint" type="continuous">
    <parent link="rear_shaft"/>
    <child link="rear_right_wheel"/>
    <origin rpy="0 0 0" xyz="0 -0.14 0"/>
    <axis xyz="0 1 0"/>
    <limit effort="10" velocity="100"/>
  </joint>
  <link name="rear_left_wheel">
    <visual>
      <material name="black"/>
      <origin rpy="1.57 0 0" xyz="0 0 0"/>
      <geometry>
        <cylinder length="0.064" radius="0.07"/>
      </geometry>
    </visual>
  </link>
  <joint name="rear_left_wheel_joint" type="continuous">
    <parent link="rear_shaft"/>
    <child link="rear_left_wheel"/>
    <origin rpy="0 0 0" xyz="0 0.14 0"/>
    <axis xyz="0 1 0"/>
    <limit effort="10" velocity="100"/>
  </joint>
  <material name="black">
    <color rgba="0.0 0.0 0.0 1.0"/>
  </material>
  <material name="blue">
    <color rgba="0.0 0.0 0.8 1.0"/>
  </material>
  <material name="green">
    <color rgba="0.0 0.8 0.0 1.0"/>
  </material>
  <material name="grey">
    <color rgba="0.2 0.2 0.2 1.0"/>
  </material>
  <material name="orange">
    <color rgba="1.0 0.423529411765 0.0392156862745 1.0"/>
  </material>
  <material name="brown">
    <color rgba="0.870588235294 0.811764705882 0.764705882353 1.0"/>
  </material>
  <material name="red">
    <color rgba="0.8 0.0 0.0 1.0"/>
  </material>
  <material name="white">
    <color rgba="1.0 1.0 1.0 1.0"/>
  </material>
  <material name="acrylic">
    <color rgba="1.0 1.0 1.0 0.4"/>
  </material>
</robot>

 

7. 실행

빌드

cm

 

실행

roslaunch rviz_xycar xycar_3d.launch

실행했는데 rviz에 아무것도 안나와서 당황했다.

 

두가지 설정

1) Fixed Frame : base_link

2) TF, RobotModel 추가

 

아래 예제에서도 했던 설정이다.

2021/01/20 - [ROS] - Ubuntu16.04 ROS Kinetic - ex_urdf 패키지. RVIZ 회전막대 모델

Ubuntu16.04 ROS Kinetic - ex_urdf 패키지. RVIZ 회전막대 모델

 

 

 

마지막에 종료할 때 ~/xycar_ws/src/rviz_xycar/rviz 위치에 xycar_3d.rviz로 저장하였다.