MSCFModel_Kerner.cpp

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/****************************************************************************/
// car-following model by B. Kerner
/****************************************************************************/
// SUMO, Simulation of Urban MObility; see http://sumo.sourceforge.net/
// Copyright (C) 2001-2011 DLR (http://www.dlr.de/) and contributors
/****************************************************************************/
//
//   This program is free software; you can redistribute it and/or modify
//   it under the terms of the GNU General Public License as published by
//   the Free Software Foundation; either version 2 of the License, or
//   (at your option) any later version.
//
/****************************************************************************/


// ===========================================================================
// included modules
// ===========================================================================
#ifdef _MSC_VER
#include <windows_config.h>
#else
#include <config.h>
#endif

#include <microsim/MSVehicle.h>
#include <microsim/MSLane.h>
#include "MSCFModel_Kerner.h"
#include <utils/common/RandHelper.h>


// ===========================================================================
// method definitions
// ===========================================================================
MSCFModel_Kerner::MSCFModel_Kerner(const MSVehicleType* vtype, SUMOReal accel,
                                   SUMOReal decel, SUMOReal headwayTime, SUMOReal k, SUMOReal phi)
    : MSCFModel(vtype, accel, decel, headwayTime), myK(k), myPhi(phi), myTauDecel(decel* headwayTime) {
}


MSCFModel_Kerner::~MSCFModel_Kerner() {}


SUMOReal
MSCFModel_Kerner::followSpeed(const MSVehicle* const /*veh*/, SUMOReal speed, SUMOReal gap, SUMOReal predSpeed, SUMOReal /*predMaxDecel*/) const {
    return MIN2(_v(speed, maxNextSpeed(speed), gap, predSpeed), maxNextSpeed(speed));
}


SUMOReal
MSCFModel_Kerner::stopSpeed(const MSVehicle* const veh, SUMOReal gap) const {
    const SUMOReal speed = veh->getSpeed();
    return MIN2(_v(speed, maxNextSpeed(speed), gap, 0), maxNextSpeed(speed));
}


SUMOReal
MSCFModel_Kerner::_v(SUMOReal speed, SUMOReal vfree, SUMOReal gap, SUMOReal predSpeed) const {
    if (predSpeed==0&&gap<0.01) {
        return 0;
    }
    // !!! in the following, the prior step is not considered!!!
    SUMOReal G = MAX2((SUMOReal) 0, (SUMOReal)(SPEED2DIST(myK*speed)+myPhi/myAccel*speed*(speed-predSpeed)));
    SUMOReal vcond = gap>G ? speed+ACCEL2SPEED(myAccel) : speed+MAX2(ACCEL2SPEED(-myDecel), MIN2(ACCEL2SPEED(myAccel), predSpeed-speed));
    SUMOReal vsafe = (SUMOReal)(-1. * myTauDecel + sqrt(myTauDecel*myTauDecel + (predSpeed*predSpeed) + (2. * myDecel * gap)));
    SUMOReal va = MAX2((SUMOReal) 0, MIN3(vfree, vsafe, vcond)) + RandHelper::rand();
    SUMOReal v = MAX2((SUMOReal) 0, MIN4(vfree, va, speed+ACCEL2SPEED(myAccel), vsafe));
    return v;
}


MSCFModel*
MSCFModel_Kerner::duplicate(const MSVehicleType* vtype) const {
    return new MSCFModel_Kerner(vtype, myAccel, myDecel, myHeadwayTime, myK, myPhi);
}