写一个二驱循迹小车pwm调速代码

好的，这是一个基于Arduino平台的二驱循迹小车PWM调速代码示例：

// 定义左右电机驱动引脚
#define LEFT_MOTOR_PIN1 5
#define LEFT_MOTOR_PIN2 6
#define RIGHT_MOTOR_PIN1 9
#define RIGHT_MOTOR_PIN2 10

// 定义左右电机PWM控制引脚
#define LEFT_MOTOR_PWM 3
#define RIGHT_MOTOR_PWM 11

// 定义循迹传感器引脚
#define SENSOR_PIN1  A0
#define SENSOR_PIN2  A1
#define SENSOR_PIN3  A2
#define SENSOR_PIN4  A3
#define SENSOR_PIN5  A4

// 定义调速变量
int leftSpeed = 0;
int rightSpeed = 0;

void setup() {
  // 配置电机驱动引脚为输出模式
  pinMode(LEFT_MOTOR_PIN1, OUTPUT);
  pinMode(LEFT_MOTOR_PIN2, OUTPUT);
  pinMode(RIGHT_MOTOR_PIN1, OUTPUT);
  pinMode(RIGHT_MOTOR_PIN2, OUTPUT);

  // 配置电机PWM引脚为输出模式
  pinMode(LEFT_MOTOR_PWM, OUTPUT);
  pinMode(RIGHT_MOTOR_PWM, OUTPUT);

  // 初始化串口
  Serial.begin(9600);
}

void loop() {
  // 读取循迹传感器数据
  int sensor1 = analogRead(SENSOR_PIN1);
  int sensor2 = analogRead(SENSOR_PIN2);
  int sensor3 = analogRead(SENSOR_PIN3);
  int sensor4 = analogRead(SENSOR_PIN4);
  int sensor5 = analogRead(SENSOR_PIN5);

  // 计算偏差值
  int error = sensor1 * 1 + sensor2 * 2 + sensor3 * 3 + sensor4 * 2 + sensor5 * 1 - 1000;

  // 根据偏差值调整左右电机PWM占空比
  leftSpeed = 100 - error * 0.2;
  rightSpeed = 100 + error * 0.2;

  // 限制PWM占空比范围
  leftSpeed = constrain(leftSpeed, 0, 100);
  rightSpeed = constrain(rightSpeed, 0, 100);

  // 控制电机转速
  analogWrite(LEFT_MOTOR_PWM, leftSpeed * 255 / 100);
  analogWrite(RIGHT_MOTOR_PWM, rightSpeed * 255 / 100);

  // 控制电机方向
  if (leftSpeed > 0) {
    digitalWrite(LEFT_MOTOR_PIN1, HIGH);
    digitalWrite(LEFT_MOTOR_PIN2, LOW);
  } else {
    digitalWrite(LEFT_MOTOR_PIN1, LOW);
    digitalWrite(LEFT_MOTOR_PIN2, HIGH);
  }

  if (rightSpeed > 0) {
    digitalWrite(RIGHT_MOTOR_PIN1, HIGH);
    digitalWrite(RIGHT_MOTOR_PIN2, LOW);
  } else {
    digitalWrite(RIGHT_MOTOR_PIN1, LOW);
    digitalWrite(RIGHT_MOTOR_PIN2, HIGH);
  }

  // 打印调试信息
  Serial.print("Error: ");
  Serial.print(error);
  Serial.print(", Left Speed: ");
  Serial.print(leftSpeed);
  Serial.print(", Right Speed: ");
  Serial.println(rightSpeed);

  // 延时一段时间
  delay(20);
}

该代码中使用了循迹传感器读取数据，并根据偏差值调整左右电机PWM占空比，从而实现小车的循迹行驶。同时，还对PWM占空比范围进行了限制，并控制电机的转速和方向。最后，通过串口打印调试信息，方便调试和优化程序。