Arduino智能小车调速
1、驱动模块接线
在前面的教程中已经讲过如果想控制驱动的输出时，需要对驱动的“ENA”“ENB”进行控制，因此我们需要将图中被选中部分的两个跳线帽拔掉。并将“ENA”连接Arduino UNO开发板的“5”引脚，“ENB”连接“6”引脚。
2、Arduino代码测试如下：
int leftCounter=0, rightCounter=0;
unsigned long time = 0, old_time = 0; // 时间标记
unsigned long time1 = 0; // 时间标记
float lv,rv;//左、右轮速度
#define STOP 0
#define FORWARD 1
#define BACKWARD 2
#define TURNLEFT 3
#define TURNRIGHT 4
#define CHANGESPEED 5
int leftMotor1 = 16;
int leftMotor2 = 17;
int rightMotor1 = 18;
int rightMotor2 = 19;
bool speedLevel=0;
int leftPWM = 5;
int rightPWM = 6;
void setup() {
// put your setup code here, to run once:
Serial.begin(9600);
attachInterrupt(0,RightCount_CallBack, FALLING);
attachInterrupt(1,LeftCount_CallBack, FALLING);
pinMode(leftMotor1, OUTPUT);
pinMode(leftMotor2, OUTPUT);
pinMode(rightMotor1, OUTPUT);
pinMode(rightMotor2, OUTPUT);
pinMode(leftPWM, OUTPUT);
pinMode(rightPWM, OUTPUT);
}
void loop() {
// put your main code here, to run repeatedly:
SpeedDetection();
if(Serial.available()>0)
{
char cmd = Serial.read();
Serial.print(cmd);
motorRun(cmd);
if(speedLevel) //根据不通的档位输出不同速度
{
analogWrite(leftPWM, 120);
analogWrite(rightPWM, 120);
}
else
{
analogWrite(leftPWM, 250);
analogWrite(rightPWM, 250);
}
}
}
/*
* *速度计算
*/
bool SpeedDetection()
{
time = millis();//以毫秒为单位，计算当前时间
if(abs(time - old_time) >= 1000) // 如果计时时间已达1秒
{
detachInterrupt(0); // 关闭外部中断0
detachInterrupt(1); // 关闭外部中断1
//把每一秒钟编码器码盘计得的脉冲数，换算为当前转速值
//转速单位是每分钟多少转，即r/min。这个编码器码盘为20个空洞。
Serial.print("left:");
lv =(float)leftCounter*60/20;//小车车轮电机转速
rv =(float)rightCounter*60/20;//小车车轮电机转速
Serial.print("left:");
Serial.print(lv);//向上位计算机上传左车轮电机当前转速的高、低字节
Serial.print(" right:");
Serial.println(rv);//向上位计算机上传左车轮电机当前转速的高、低字节
//恢复到编码器测速的初始状态
leftCounter = 0; //把脉冲计数值清零，以便计算下一秒的脉冲计数
rightCounter = 0;
old_time= millis(); // 记录每秒测速时的时间节点
attachInterrupt(0, RightCount_CallBack,FALLING); // 重新开放外部中断0
attachInterrupt(1, LeftCount_CallBack,FALLING); // 重新开放外部中断0
return 1;
}
else
return 0;
}
/*
* *右轮编码器中断服务函数
*/
void RightCount_CallBack()
{
rightCounter++;
}
/*
* *左轮编码器中断服务函数
*/
void LeftCount_CallBack()
{
leftCounter++;
}
/*
* *小车运动控制函数
*/
void motorRun(int cmd)
{
switch(cmd){
case FORWARD:
Serial.println("FORWARD"); //输出状态
digitalWrite(leftMotor1, HIGH);
digitalWrite(leftMotor2, LOW);
digitalWrite(rightMotor1, HIGH);
digitalWrite(rightMotor2, LOW);
break;
case BACKWARD:
Serial.println("BACKWARD"); //输出状态
digitalWrite(leftMotor1, LOW);
digitalWrite(leftMotor2, HIGH);
digitalWrite(rightMotor1, LOW);
digitalWrite(rightMotor2, HIGH);
break;
case TURNLEFT:
Serial.println("TURN LEFT"); //输出状态
digitalWrite(leftMotor1, HIGH);
digitalWrite(leftMotor2, LOW);
digitalWrite(rightMotor1, LOW);
digitalWrite(rightMotor2, HIGH);
break;
case TURNRIGHT:
Serial.println("TURN RIGHT"); //输出状态
digitalWrite(leftMotor1, LOW);
digitalWrite(leftMotor2, HIGH);
digitalWrite(rightMotor1, HIGH);
digitalWrite(rightMotor2, LOW);
break;
case CHANGESPEED:
Serial.println("CHANGE SPEED"); //输出状态
if(speedLevel) //接收到换挡命令的时候切换档位
speedLevel=0;
else
speedLevel=1;
break;
default:
Serial.println("STOP"); //输出状态
digitalWrite(leftMotor1, LOW);
digitalWrite(leftMotor2, LOW);
digitalWrite(rightMotor1, LOW);
digitalWrite(rightMotor2, LOW);
}
}
3、为了便于大家理解，这里特意在解释一下：
在主函数void loop()中添加PWM输出的函数，analogWrite(pin, value)函数中“pin”代表使用的引脚，“value”代表输出PWM值的大小，范围是0~255。
if(speedLevel) //根据不通的档位输出不同速度
{
analogWrite(leftPWM, 120); analogWrite(rightPWM, 120);
}
else
{
analogWrite(leftPWM, 250); analogWrite(rightPWM, 250);
}
