arduino 小车走直线pid程序书写

Arduino小车直线行走的PID（比例积分微分）控制程序通常用于精确地调整电机的速度或方向，以使车辆沿预定路径行驶。PID控制器是一种常用的算法，用于跟踪目标值，它结合了三个参数：

1. 比例(P)：当前误差（目标值 - 实际位置）
2. 积分(I)：累积过去的误差，消除长期趋势
3. 微分(D)：预测未来的误差变化，快速响应变化

以下是编写基本PID控制小车直线运动的步骤：

// Arduino PID Class Example
class PID {
public:
    PID(float setpoint, float Kp, float Ki, float Kd, int sample_time = 10) {
        _setpoint = setpoint;
        _Kp = Kp;
        _Ki = Ki;
        _Kd = Kd;
        _sample_time = sample_time;
        _prev_error = 0;
        _integral = 0;
    }

    void update(float input) {
        float error = _setpoint - input;
        _integral += error * _sample_time;

        // Proportional term
        float P = _Kp * error;

        // Integral term (limited to avoid overflow)
        if (_integral > LIMIT) {
            _integral = LIMIT;
        } else if (_integral < -LIMIT) {
            _integral = -LIMIT;
        }
        float I = _Ki * _integral;

        // Derivative term
        float D = 0; // In this simple case, we often don't use derivative for motor control due to noise and computation overhead
        // If you choose to use it, calculate with the change in error over time.

        // Total output is sum of all three terms
        float output = P + I + D;

        // Update your motor speed or direction based on 'output'
    }

private:
    float _setpoint;
    float _Kp, _Ki, _Kd;
    const int _sample_time;
    float _prev_error, _integral;
    static const float LIMIT = 1000; // Limit integral term to prevent overflow
};

// In your main loop:
PID pid(50, 0.1, 0.01, 0); // Assuming target setpoint is 50, tuning constants
analogReadFromSensor(); // Read sensor data from the car's position sensor
pid.update(sensorValue);
setMotorSpeed(pid.output); // Adjust motor speed according to PID output

在这个例子中，你需要替换`analogReadFromSensor()`和`setMotorSpeed()`函数以获取传感器数据并控制电机。