SUMO - Simulation of Urban MObility
MSCFModel_Kerner.cpp
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00001 /****************************************************************************/
00009 // car-following model by B. Kerner
00010 /****************************************************************************/
00011 // SUMO, Simulation of Urban MObility; see http://sumo.sourceforge.net/
00012 // Copyright (C) 2001-2012 DLR (http://www.dlr.de/) and contributors
00013 /****************************************************************************/
00014 //
00015 //   This file is part of SUMO.
00016 //   SUMO is free software: you can redistribute it and/or modify
00017 //   it under the terms of the GNU General Public License as published by
00018 //   the Free Software Foundation, either version 3 of the License, or
00019 //   (at your option) any later version.
00020 //
00021 /****************************************************************************/
00022 
00023 
00024 // ===========================================================================
00025 // included modules
00026 // ===========================================================================
00027 #ifdef _MSC_VER
00028 #include <windows_config.h>
00029 #else
00030 #include <config.h>
00031 #endif
00032 
00033 #include <microsim/MSVehicle.h>
00034 #include <microsim/MSLane.h>
00035 #include "MSCFModel_Kerner.h"
00036 #include <utils/common/RandHelper.h>
00037 
00038 
00039 // ===========================================================================
00040 // method definitions
00041 // ===========================================================================
00042 MSCFModel_Kerner::MSCFModel_Kerner(const MSVehicleType* vtype, SUMOReal accel,
00043                                    SUMOReal decel, SUMOReal headwayTime, SUMOReal k, SUMOReal phi)
00044     : MSCFModel(vtype, accel, decel, headwayTime), myK(k), myPhi(phi), myTauDecel(decel* headwayTime) {
00045 }
00046 
00047 
00048 MSCFModel_Kerner::~MSCFModel_Kerner() {}
00049 
00050 
00051 SUMOReal
00052 MSCFModel_Kerner::followSpeed(const MSVehicle* const /*veh*/, SUMOReal speed, SUMOReal gap, SUMOReal predSpeed, SUMOReal /*predMaxDecel*/) const {
00053     return MIN2(_v(speed, maxNextSpeed(speed), gap, predSpeed), maxNextSpeed(speed));
00054 }
00055 
00056 
00057 SUMOReal
00058 MSCFModel_Kerner::stopSpeed(const MSVehicle* const veh, SUMOReal gap) const {
00059     const SUMOReal speed = veh->getSpeed();
00060     return MIN2(_v(speed, maxNextSpeed(speed), gap, 0), maxNextSpeed(speed));
00061 }
00062 
00063 
00064 SUMOReal
00065 MSCFModel_Kerner::_v(SUMOReal speed, SUMOReal vfree, SUMOReal gap, SUMOReal predSpeed) const {
00066     if (predSpeed == 0 && gap < 0.01) {
00067         return 0;
00068     }
00069     // !!! in the following, the prior step is not considered!!!
00070     SUMOReal G = MAX2((SUMOReal) 0, (SUMOReal)(SPEED2DIST(myK * speed) + myPhi / myAccel * speed * (speed - predSpeed)));
00071     SUMOReal vcond = gap > G ? speed + ACCEL2SPEED(myAccel) : speed + MAX2(ACCEL2SPEED(-myDecel), MIN2(ACCEL2SPEED(myAccel), predSpeed - speed));
00072     SUMOReal vsafe = (SUMOReal)(-1. * myTauDecel + sqrt(myTauDecel * myTauDecel + (predSpeed * predSpeed) + (2. * myDecel * gap)));
00073     SUMOReal va = MAX2((SUMOReal) 0, MIN3(vfree, vsafe, vcond)) + RandHelper::rand();
00074     SUMOReal v = MAX2((SUMOReal) 0, MIN4(vfree, va, speed + ACCEL2SPEED(myAccel), vsafe));
00075     return v;
00076 }
00077 
00078 
00079 MSCFModel*
00080 MSCFModel_Kerner::duplicate(const MSVehicleType* vtype) const {
00081     return new MSCFModel_Kerner(vtype, myAccel, myDecel, myHeadwayTime, myK, myPhi);
00082 }
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