3. 电子硬件
在这个示例中，我们采用了以下硬件，请大家参考：
| 主控板 | |
| 扩展板 | |
| 电池 | 7.4V锂电池 |
| 通信 | 2510通信转接板 |
| WiFi路由器 | |
| 其它 | 摄像头 |
| 配置 OpenCV的Visual Studio 2015.net环境 的计算机一台 |
电路连接说明：
① 将2510通信转接板连接到Bigfish扩展板的扩展坞上面；
② 用3根母对母杜邦线将2510通信转接板与WiFi路由器连接起来：GND-GND、RX-RX、TX-TX；
③ 找到1根USB线，一端连接到2510通信转接板接口上，另一端连接到WiFi路由器USB接口上；
④ 将摄像头线连接到WiFi路由器接口上。
4. 功能实现
实现思路：实现双轮云台小车追踪蓝色小球。
4.1 工作原理
① 摄像头采集图像信息；
② 通过WiFi将信息传递给PC端（VS2015配置的OpenCV环境）；
③ 使用OpenCV的目标颜色跟踪camshift算法取得目标物体的中心点坐标；
④ 采用九宫格方式对摄像显示图像进行分割；
⑤ 确定目标物体在显示图像的所处九宫格位置；
⑥ 如果目标图像超出九宫格位置的中心，调整摄像头矫正偏移使目标物体在屏幕中心位置；
⑦ 调整摄像头需要上位机通过WiFi给下位机发送矫正指令，下位机需要接收信号，并且让安装了摄像头的智能小车做出相应的矫正动作，
如果丢失目标，智能车上的云台会转动以寻找目标。
4.2 示例程序
编程环境：Arduino 1.8.19
① 下位机例程
将参考例程（example.ino）下载到主控板，打开路由器，待路由器完成启动后，将路由器与主控板的TX、RX串口连接，同时将PC连接至路由器WIFI网络。下位机接收上位机处理的图像信息结果控制云台相应运动，云台跟随目标物体运动。
/*------------------------------------------------------------------------------------
版权说明：Copyright 2023 Robottime(Beijing) Technology Co., Ltd. All Rights Reserved.
Distributed under MIT license.See file LICENSE for detail or copy at
https://opensource.org/licenses/MIT
by 机器谱 2023-04-24 https://www.robotway.com/
------------------------------*/
/*
car_exapmle
2018/06/07
---------------------
Motor:
left: 9,5
right: 10,6
Servo:
bottom:4
top:7
*/
#include <Servo.h>
#define BOTTOM_SERVO_MIN 60
#define BOTTOM_SERVO_MAX 150 //175
#define BOTTOM_SERVO_MIDDLE 85
#define TOP_SERVO_MIN 85
#define TOP_SERVO_MAX 175
const String CMD_LEFT = "L";
const String CMD_RIGHT = "R";
const String CMD_STOP = "S";
const String CMD_FORWARD = "F";
const String CMD_LOST = "N";
Servo myServo[2];
int port0 = 4;
int port1 = 7;
int servo_value[2] = {85, 105};
int servo_move_angle = 1;
void setup() {
Serial.begin(9600);
pinMode(5,OUTPUT);
pinMode(6,OUTPUT);
pinMode(9,OUTPUT);
pinMode(10,OUTPUT);
ServoInit();
delay(1000);
}
void loop() {
String data = SerialRead();
if(data == CMD_STOP)
{
Stop();
}
else if(data == CMD_FORWARD)
{
Forward();
}
else if(data == CMD_LEFT)
{
Left();
delay(60);
Stop();
}
else if(data == CMD_RIGHT)
{
Right();
delay(60);
Stop();
}
else if(data == CMD_LOST)
{
FindObject();
}
}
String SerialRead()
{
String str = "";
while(Serial.available())
{
str += char(Serial.read());
}
return str;
}
int Angle2Pwm(int n)
{
return map(n, 0, 180, 500, 2500);
}
void ServoInit()
{
myServo[0].attach(port0);
myServo[1].attach(port1);
for(int i=0;i<2;i++)
{
myServo[i].write(Angle2Pwm(servo_value[i]));
}
}
void FindObject()
{
const int times = 30;
int dir = 0;
for(;;)
{
String data = SerialRead();
if(data != CMD_LOST && data != "")
{
if(servo_value[0] <= BOTTOM_SERVO_MIDDLE)
{
dir = 1; // turn left
for(int i=0;i<abs(servo_value[0] - BOTTOM_SERVO_MIDDLE);i++)
{
servo_value[0] += 1;
myServo[0].write(Angle2Pwm(servo_value[0]));
delay(times);
}
}
else if(servo_value[0] > BOTTOM_SERVO_MIDDLE)
{
dir = 2; // turn right
for(int i=0;i<abs(servo_value[0] - BOTTOM_SERVO_MIDDLE);i++)
{
servo_value[0] -= 1;
myServo[0].write(Angle2Pwm(servo_value[0]));
delay(times);
}
}
break;
}
if(servo_value[0] <= BOTTOM_SERVO_MIN)
{
servo_move_angle = 1;
servo_value[0] = BOTTOM_SERVO_MIN;
}
else if(servo_value[0] >= BOTTOM_SERVO_MAX)
{
servo_move_angle = -1;
servo_value[0] = BOTTOM_SERVO_MAX;
}
servo_value[0] += servo_move_angle;
myServo[0].write(Angle2Pwm(servo_value[0]));
delay(times);
}
if(dir == 1)
{
Left();
delay(500);
Stop();
}
else if(dir == 2)
{
Right();
delay(500);
Stop();
}
}
void Forward()
{
analogWrite(5,120);
analogWrite(6,0);
analogWrite(9,120);
analogWrite(10,0);
}
void Left()
{
analogWrite(5,105);
analogWrite(6,0);
analogWrite(9,0);
analogWrite(10,105);
}
void Right()
{
analogWrite(5,0);
analogWrite(6,105);
analogWrite(9,105);
analogWrite(10,0);
}
void Stop()
{
digitalWrite(5,HIGH);
digitalWrite(6,HIGH);
digitalWrite(9,HIGH);
digitalWrite(10,HIGH);
}② 上位机例程
下面提供一个可以实现双轮智能小车追踪蓝色小球的参考例程（MainWindow.xaml.cs），大家可参考演示视频完成该实验。
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using System.Windows.Navigation;
using System.Windows.Shapes;
using System.Windows.Forms;
using System.Runtime.InteropServices;
using System.Threading;
using System.Net;
using System.Net.Sockets;
namespace Project
{
/// <summary>
/// 云台跟踪
/// </summary>
public partial class MainWindow : Window
{
//导入 camshift.dll 动态链接库
[DllImport("Camshift_DLL.dll", CharSet = CharSet.Ansi)]
public static extern void Camshift([MarshalAs(UnmanagedType.LPStr)]string ip_address, //图片或视频地址
ref int xpos, //检测框中心X坐标
ref int ypos, //检测框中心Y坐标
ref int td); //检测区域对角线长度
//定义窗口大小
int cap_w = 320, cap_h = 240;
//跟踪物体中心 x, y 坐标值
int x = 0, y = 0, d = 0;
//定义命令变量
string CMD_FORWARD = "", CMD_TURN_LEFT = "", CMD_TURN_RIGHT = "", CMD_STOP = "", CMD_LOST = "";
//结构体
public struct Boundaries
{
public int x_left;
public int x_right;
public int y_up;
public int y_down;
public int d_min;
public int d_max;
}
Boundaries boundaries = new Boundaries();
public MainWindow()
{
InitializeComponent();
}
private void Window_Loaded(object sender, RoutedEventArgs e)
{
GetIni();
SetPosition();
CmdInit();
StructInit();
}
//变量初始化
private void CmdInit()
{
CMD_FORWARD = "F";
CMD_TURN_LEFT = "L";
CMD_TURN_RIGHT = "R";
CMD_STOP = "S";
CMD_LOST = "N";
}
//结构体初始化
private void StructInit()
{
boundaries.x_left = 120;
boundaries.x_right = 240;
boundaries.y_up = 80;
boundaries.y_down = 160;
boundaries.d_min = 50;
boundaries.d_max = 150;
}
//获取ini配置文件信息
private void GetIni()
{
ini_RW.FileName = System.Windows.Forms.Application.StartupPath + "\\Config.ini";
this.videoAddress.Text = ini_RW.ReadIni("VideoUrl", "videourl", "");
this.ipAddress.Text = ini_RW.ReadIni("ControlUrl", "controlUrl", "");
this.portBox.Text = ini_RW.ReadIni("ControlPort", "controlPort", "");
}
//修改配置
private void setBtn_Click(object sender, RoutedEventArgs e)
{
ini_RW.WriteIni("VideoUrl", "videourl", this.videoAddress.Text);
ini_RW.WriteIni("ControlUrl", "controlUrl", this.ipAddress.Text);
ini_RW.WriteIni("ControlPort", "controlPort", this.portBox.Text);
System.Windows.MessageBox.Show("配置成功！请重启程序以使配置生效。",
"配置信息", MessageBoxButton.OK,
MessageBoxImage.Information);
//this.Close();
}
//命令发送函数
void SendData(string data)
{
try
{
IPAddress ips = IPAddress.Parse(ipAddress.Text.ToString());//("192.168.8.1");
IPEndPoint ipe = new IPEndPoint(ips, Convert.ToInt32(portBox.Text.ToString()));//把ip和端口转化为IPEndPoint实例
Socket c = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);//创建一个Socket
c.Connect(ipe);//连接到服务器
byte[] bs = Encoding.ASCII.GetBytes(data);
c.Send(bs, bs.Length, 0);//发送测试信息
c.Close();
}
catch (Exception e)
{
System.Windows.Forms.MessageBox.Show(e.Message);
}
}
//跟踪物体位置界限判断
private void LineDetect(int _x, int _y, int _d)
{
try
{
//判断转动方向
if (_x > 0 && _x <= boundaries.x_left)
{
SendData(CMD_TURN_LEFT);
}
else if (x > boundaries.x_right && x < cap_w)
{
SendData(CMD_TURN_RIGHT);
}
//判断是否前进
else if (_d > boundaries.d_min && _d < boundaries.d_max)
{
SendData(CMD_FORWARD);
}
else if ((_x > boundaries.x_left && _x < boundaries.x_right)&&
(_d >= 0 && _d <= boundaries.d_min ))
{
SendData(CMD_LOST);
}
else
{
SendData(CMD_STOP);
}
}
catch { };
}
//物体位置初始化
private void SetPosition()
{
var color = new SolidColorBrush((System.Windows.Media.Color)System.Windows.Media.ColorConverter.ConvertFromString("#FFACAAAA"));
objEllipse.Height = 30;
objEllipse.Width = 30;
objEllipse.Fill = color;
var left_distance = (cap_w - objEllipse.Width) / 2;
var top_distance = (cap_h - objEllipse.Height) / 2;
Canvas.SetLeft(objEllipse, left_distance);
Canvas.SetTop(objEllipse, top_distance);
}
//跟踪物体位置更新函数
private void PositionUpdate(int x, int y, int d)
{
LineDetect(x, y, d);
Canvas.SetLeft(objEllipse, x);
Canvas.SetTop(objEllipse, y);
posLable.Content = x + " , " + y + " , " + d;
}
//线程函数
private void ThreadCapShow()
{
try
{
while (true)
{
this.Dispatcher.Invoke(
new Action(
delegate
{
string ip = this.videoAddress.Text;
Camshift(ip, ref x, ref y, ref d);
PositionUpdate(x - 15, y - 15, d);
}
));
}
}
catch { };
}
//打开跟踪窗口
private void openBtn_Click(object sender, RoutedEventArgs e)
{
try
{
Thread m_thread = new Thread(ThreadCapShow);
m_thread.IsBackground = true;
m_thread.Start();
}
catch { };
}
}
}例程源代码、样机3D文件资料内容详见 双轮云台小车-追踪彩色目标