用红外循迹传感器和pid控制差速转向的小车的代码

下面是使用红外循迹传感器和PID控制算法控制差速转向小车的示例代码，使用Arduino IDE编写：

//定义红外循迹传感器的引脚号
#define LEFT_SENSOR A0
#define RIGHT_SENSOR A1

//定义电机控制引脚号
#define LEFT_MOTOR_PIN 5
#define RIGHT_MOTOR_PIN 6

//定义PID控制算法的参数
#define KP 1.2
#define KI 5
#define KD 0.1

//定义PID控制器
class PIDController {
  private:
    double _kp, _ki, _kd;
    double _targetValue;
    double _error, _lastError, _sumError;
    unsigned long _lastTime;
  public:
    PIDController(double kp, double ki, double kd) {
      _kp = kp;
      _ki = ki;
      _kd = kd;
      _targetValue = 0;
      _error = 0;
      _lastError = 0;
      _sumError = 0;
      _lastTime = millis();
    }
    void setTargetValue(double targetValue) {
      _targetValue = targetValue;
    }
    double compute(double inputValue) {
      unsigned long currentTime = millis();
      double deltaTime = (double)(currentTime - _lastTime) / 1000;
      _lastTime = currentTime;
      _error = _targetValue - inputValue;
      _sumError += _error * deltaTime;
      double deltaError = (_error - _lastError) / deltaTime;
      _lastError = _error;
      double outputValue = _kp * _error + _ki * _sumError + _kd * deltaError;
      return outputValue;
    }
};

//定义PID控制器实例
PIDController pid(KP, KI, KD);

void setup() {
  pinMode(LEFT_SENSOR, INPUT);
  pinMode(RIGHT_SENSOR, INPUT);
  pinMode(LEFT_MOTOR_PIN, OUTPUT);
  pinMode(RIGHT_MOTOR_PIN, OUTPUT);
  pid.setTargetValue(0.5); //设置目标值为0.5
}

void loop() {
  //读取红外循迹传感器的值
  int leftSensorValue = analogRead(LEFT_SENSOR);
  int rightSensorValue = analogRead(RIGHT_SENSOR);
  double sensorValue = (double)(leftSensorValue + rightSensorValue) / 2.0 / 1023.0;
  //计算PID控制算法的输出值
  double outputValue = pid.compute(sensorValue);
  //将输出值转换成电机控制信号
  int leftMotorSpeed = 255 * (1 - outputValue);
  int rightMotorSpeed = 255 * (1 + outputValue);
  //控制小车的转向
  analogWrite(LEFT_MOTOR_PIN, leftMotorSpeed);
  analogWrite(RIGHT_MOTOR_PIN, rightMotorSpeed);
}

上述代码中，首先定义了红外循迹传感器的引脚号和电机控制引脚号。然后定义了PID控制器的参数和实例，包括比例系数、积分系数、微分系数、目标值和误差等。在`setup()`函数中，初始化了引脚和目标值。在`loop()`函数中，读取红外循迹传感器的值，并根据PID控制算法计算输出值。最后将输出值转换成电机控制信号，控制小车的转向。