Project-XJKJ/XJKJ-rdimm/XJKJ_QT/pid.cpp

#include "pid.h"
#include <QtMath>


PID::PID()
{
    //-----------------------------------------
    // PID参数
    //-----------------------------------------

    kp = 4.0;
    ki = 0.02;
    kd = 2.0;

    integral = 0;
    lastError = 0;

    // 积分最大值
    integralMax = 100;
}


//====================================================
// 加热控制
//====================================================

double PID::calculate(double target, double current)
{
    // PID执行周期
    const double dt = 0.5;

    double error = target - current;


    //-----------------------------------------
    // 1. 65℃以前
    //
    // 快速升温
    //-----------------------------------------

    if(current < 65.0)
    {
        integral = 0;
        lastError = error;

        return 100.0;
    }


    //-----------------------------------------
    // 2. 65~68℃
    //
    // 开始提前降低加热功率
    //
    // 65℃ -> 80%
    // 68℃ -> 40%
    //-----------------------------------------

    if(current < 68.0)
    {
        integral = 0;
        lastError = error;

        double duty = 80.0 - (current - 65.0) / 3.0 * 40.0;

        return qBound(0.0, duty, 100.0);
    }


    //-----------------------------------------
    // 3. 68℃以后
    //
    // 正式进入PID控温
    //-----------------------------------------

    //-----------------------------------------
    // 积分
    //-----------------------------------------

    integral += error * dt;

    integral = qBound(-integralMax,integral,integralMax);


    //-----------------------------------------
    // 微分
    //-----------------------------------------

    double derivative = (error - lastError) / dt;

    lastError = error;


    //-----------------------------------------
    // PID
    //-----------------------------------------

    double output =
            kp * error +
            ki * integral +
            kd * derivative;


    //-----------------------------------------
    // 4. 70℃附近
    //
    // 防止到达目标后继续大功率加热
    //-----------------------------------------

    if(current >= 70.0)
    {
        if(output > 25.0)
            output = 25.0;
    }


    //-----------------------------------------
    // 5. 71℃以后
    //
    // 进一步限制加热
    //-----------------------------------------

    if(current >= 71.0)
    {
        if(output > 10.0)
            output = 10.0;
    }


    //-----------------------------------------
    // 6. 72℃保护
    //
    // 超过控制范围，停止加热
    //-----------------------------------------

    if(current >= 72.0)
    {
        output = 0.0;

        // 清除积分，避免降温后仍然异常
        integral = 0;
    }


    //-----------------------------------------
    // 最终限幅
    //-----------------------------------------

    return qBound(0.0, output, 100.0);
}


//====================================================
// 风扇控制
//====================================================

double PID::calculateFanDuty(double temp)
{
    double duty;


    //-----------------------------------------
    // 68℃以前
    //
    // 固定10%
    //-----------------------------------------

    if(temp < 68.0)
    {
        duty = 10.0;
    }


    //-----------------------------------------
    // 68~72℃
    //
    // 10% -> 60%
    //-----------------------------------------

    else if(temp <= 72.0)
    {
        duty = 10.0 + (temp - 68.0) / 4.0 * 50.0;
    }


    //-----------------------------------------
    // 72~75℃
    //
    // 60% -> 100%
    //-----------------------------------------

    else if(temp <= 75.0)
    {
        duty = 60.0 + (temp - 72.0) / 3.0 * 40.0;
    }


    //-----------------------------------------
    // 75℃以上
    //
    // 全速
    //-----------------------------------------

    else
    {
        duty = 100.0;
    }


    return qBound(10.0, duty, 100.0);
}


//====================================================
// 第二组风扇控制
//====================================================

double PID::calculateFanDuty1(double temp)
{
    double duty;


    //-----------------------------------------
    // 30℃以下
    //-----------------------------------------

    if(temp <= 30.0)
    {
        duty = 10.0;
    }


    //-----------------------------------------
    // 30~40℃
    //
    // 0 -> 50%
    //-----------------------------------------

    else if(temp <= 40.0)
    {
        duty = (temp - 30.0) / 10.0 * 40.0;
    }


    //-----------------------------------------
    // 40~45℃
    //
    // 50 -> 100%
    //-----------------------------------------

    else if(temp <= 45.0)
    {
        duty = 50.0 + (temp - 40.0) / 5.0 * 50.0;
    }


    //-----------------------------------------
    // 45℃以上
    //-----------------------------------------

    else
    {
        duty = 100.0;
    }


    return qBound(0.0, duty, 100.0);
}