File content as of revision 3:34f4f22b18e7:

/**
 * @author Aaron Berk
 *
 * @section LICENSE
 *
 * Copyright (c) 2010 ARM Limited
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 *
 * @section DESCRIPTION
 * 
 * A PID controller is a widely used feedback controller commonly found in
 * industry.
 *
 * This library is a port of Brett Beauregard's Arduino PID library:
 *
 *  http://www.arduino.cc/playground/Code/PIDLibrary
 *
 * The wikipedia article on PID controllers is a good place to start on
 * understanding how they work:
 *
 *  http://en.wikipedia.org/wiki/PID_controller
 *
 * For a clear and elegant explanation of how to implement and tune a
 * controller, the controlguru website by Douglas J. Cooper (who also happened
 * to be Brett's controls professor) is an excellent reference:
 *
 *  http://www.controlguru.com/
 */

/**
 * Includes
 */
#include "PID.h"

PID::PID(float tauKp, float tauKi, float tauKd) 
{

    data = 0;
    GAIN_P = tauKp;
    GAIN_I = tauKi;
    GAIN_D = tauKd;
    setInterval(0.001);
    s_dErrIntg=0; dErr_prev=0;
}
void PID::setInterval(double inter)
{
    interval = inter;
    //start();
}
void PID::Start()
{
    timer.start();
    T.attach(this,&PID::PIDctrl,interval);
    //printf("PID statr\n");
    //wait(0.1);
    //PIDctrl();
    
}
void PID::stop()
{
    timer.stop();
    T.detach();
}

void PID::Reset()
{
        dTarget=0;
        dPoint=0;
        // PI制御ゲイン
        data=0;
        s_dErrIntg=0 ,dErr_prev=0;
}
void PID::PIDctrl()
{
    double dErr;
    double dRet;
    
    // 誤差
    dErr = dTarget - dPoint;
    
    double dErrDiff = (dErr-dErr_prev)/timer.read();
    //printf("PID %f,%f,%f,%f\n",dErr,s_dErrIntg,dErrDiff,timer.read());
    // 誤差積分
    s_dErrIntg += (dErr+dErr_prev )* timer.read() /2.0;
    // 制御入力
    dRet = GAIN_P * dErr + GAIN_I * s_dErrIntg + GAIN_D*dErrDiff;
    timer.reset();
    dErr_prev = dErr;
    data = dRet;
}