前言

巡线设计

用自定义的图片设计gazebo的地板

首先我们需要设计一个gazebo的地板，这里感谢前辈的回答：参考问答

第一步：在home目录下ctrl+h显示隐藏文件

第二步：在.gazebo文件夹创建如下文件夹

mkdir ~/.gazebo/models/my_ground_plane

mkdir -p ~/.gazebo/models/my_ground_plane/materials/textures

mkdir -p ~/.gazebo/models/my_ground_plane/materials/scripts

第三步：创建材料文件

cd ~/.gazebo/models/my_ground_plane/materials/scripts

vi my_ground_plane.material

my_ground_plane.material文件如下：

material MyGroundPlane/Image

{

receive_shadows on

technique

{

pass

{

ambient 0.5 0.5 0.5 1.0

texture_unit

{

texture MyImage.png

}

}

}

}

第四步：在textures下存我们想要用的地板图片MyImage.png

如图，将它放到~/.gazebo/models/my_ground_plane/materials/textures下面

可以使用命令：

cp 你的图片路径/MyImage.png ~/.gazebo/models/my_ground_plane/materials/textures/

第五步：在my_ground_plane文件夹下，创建文件model.sdf

cd ~/.gazebo/models/my_ground_plane

vi model.sdf

model.sdf如下：

true

0 0 1

15 15

100

50

false

0 0 1

15 15

model://my_ground_plane/materials/scripts

model://my_ground_plane/materials/textures/

MyGroundPlane/Image

第六步：在my_ground_plane文件夹下，创建文件model.config，内容如下：

My Ground Plane

1.0

model.sdf

My textured ground plane.

在gazebo中导入自己的地板模型

打开gazebo：

roslaunch turtlebot_gazebo turtlebot_world.launch

在另一个终端输入下面命令打开rviz：

roslaunch turtlebot_rviz_launchers view_robot.launch --screen

点击gazebo左上角的insert插入刚才建的模型：

选择My Ground Plane：

左键点击一下然后移动鼠标拖进去：

右键models列表里删除除了自己建的地板和机器人以外的其他家具：

用gazebo的移动工具，将机器人放到线上：

用gazebo的旋转工具将机器人的摄像机对准黄线：

旋转蓝色那条，让机器人绕z轴旋转，并对准：

写脚本控制机器人巡线

创建ros工作区间

mkdir -p ~/turtlebot_ws/src

cd ~/turtlebot_ws

catkin_init_workspace

cd src

catkin_create_pkg turtlebot1 rospy geometry_msgs sensor_msgs

cd ..

catkin_make

source ./devel/setup.bash

写过滤黄线的脚本

这里使用hsv提取黄线

先百度搜索黄色的hsv最大最小值：

在turtlebot1包的src下写过滤脚本follower_color_filter.py

cd src/turtlebot1/src

vi follower_color_filter.py

rosrun turtlebot1 follower_color_filter.py

follower_color_filter.py如下：

#!/usr/bin/env python

# BEGIN ALL

import rospy, cv2, cv_bridge, numpy

from sensor_msgs.msg import Image

class Follower:

def __init__(self):

self.bridge = cv_bridge.CvBridge()

cv2.namedWindow("window", 1)

self.image_sub = rospy.Subscriber('camera/rgb/image_raw',

Image, self.image_callback)

def image_callback(self, msg):

# BEGIN BRIDGE

image = self.bridge.imgmsg_to_cv2(msg)

cv2.imshow("ori", image )

# END BRIDGE

# BEGIN HSV

hsv = cv2.cvtColor(image, cv2.COLOR_BGR2HSV)

cv2.imshow("hsv", hsv )

# END HSV

# BEGIN FILTER

lower_yellow = numpy.array([ 26, 43, 46])

upper_yellow = numpy.array([34, 255, 255])

mask = cv2.inRange(hsv, lower_yellow, upper_yellow)

# END FILTER

masked = cv2.bitwise_and(image, image, mask=mask)

cv2.imshow("window2", mask )

cv2.waitKey(3)

rospy.init_node('follower')

follower = Follower()

rospy.spin()

# END ALL

运行效果：

可以看到very nice!!!

写巡线脚本

vi follower_line.py

rosrun turtlebot1 follower_line.py

#!/usr/bin/env python

# BEGIN ALL

import rospy, cv2, cv_bridge, numpy

from sensor_msgs.msg import Image

from geometry_msgs.msg import Twist

class Follower:

def __init__(self):

self.bridge = cv_bridge.CvBridge()

cv2.namedWindow("window", 1)

self.image_sub = rospy.Subscriber('camera/rgb/image_raw',

Image, self.image_callback)

self.cmd_vel_pub = rospy.Publisher('cmd_vel_mux/input/teleop',

Twist, queue_size=1)

self.twist = Twist()

def image_callback(self, msg):

image = self.bridge.imgmsg_to_cv2(msg,desired_encoding='bgr8')

hsv = cv2.cvtColor(image, cv2.COLOR_BGR2HSV)

lower_yellow = numpy.array([ 26, 43, 46])

upper_yellow = numpy.array([34, 255, 255])

mask = cv2.inRange(hsv, lower_yellow, upper_yellow)

h, w, d = image.shape

search_top = 3*h/4

search_bot = 3*h/4 + 20

mask[0:search_top, 0:w] = 0

mask[search_bot:h, 0:w] = 0

M = cv2.moments(mask)

if M['m00'] > 0:

cx = int(M['m10']/M['m00'])

cy = int(M['m01']/M['m00'])

cv2.circle(image, (cx, cy), 20, (0,0,255), -1)

# BEGIN CONTROL

err = cx - w/2

self.twist.linear.x = 0.2

self.twist.angular.z = -float(err) / 100

self.cmd_vel_pub.publish(self.twist)

# END CONTROL

cv2.imshow("window", image)

cv2.waitKey(3)

rospy.init_node('follower')

follower = Follower()

rospy.spin()

# END ALL

运行脚本：

总结

挺好玩的吧，可以仿真下巡线的算法哈哈哈哈，做过智能车的小伙伴应该不陌生哦～

enjoy it~