wheel.h

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/***************************************************************************
 
    file                 : wheel.h
    created              : Sun Mar 19 00:09:18 CET 2000
    copyright            : (C) 2000-2017 by Eric Espie, Bernhard Wymann
    email                : torcs@free.fr
    version              : $Id$
 
 ***************************************************************************/
 
/***************************************************************************
 *                                                                         *
 *   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.                                   *
 *                                                                         *
 ***************************************************************************/
 
#ifndef _WHEEL_H__
#define _WHEEL_H__
 
#include "differential.h"
 
typedef struct
{
 
    /* internal data */
    tSuspension  susp;       /* associated suspension */
    tBrake       brake;      /* associated brake disk */
 
    /* dynamic */
    t3Dd    forces;       /* forces acting on car */
    tdble  rollRes; /* Rolling Resistance (summed over the car) */
    tdble  rideHeight;   /* height of the bottom of the car */
    tdble  zRoad;     /* z of the road */
    double  worldPosX; /* high-precision world position for track contact */
    double  worldPosY;
    tdble  worldPosZ;
    t3Dd    bodyVel; /* world related */
    tdble      driveTq;     /* engine torque */
    tdble  vt;
 
    tdble      spinTq;       /* spin torque feedback */
    tdble      spinVel;     /* spin velocity */
    tdble      prespinVel;       /* spin velocity */
    int         state;         /* wheel state */
    /* 1 and 2 are for suspension state */
#define SIM_WH_ONAIR 4  /* the wheel has no contact to the ground although the suspension is not fully extended */
    tdble  axleFz;       /* force from axle (anti-roll bar) */
    tTrkLocPos    trkPos;       /* current track position */
    t3Dd    surfaceNormal; // Normal of the surface under this wheel
    tPosd  relPos;       /* relative pos / GC */
    tdble  sa;       /* slip angle */
    tdble  sx;       /* longitudinal slip value */
    tdble  steer;
    
    /* static */
    tPosd  staticPos; /* pos relative to the GC (z is suspension travel at rest) */
                /* and angles are camber (ax), caster (ay) and toe (az) */
    tdble  rollCenter;
 
    tdble      weight0; /* initial weight on this wheel */
    tdble  tireSpringRate;
    tdble      radius;
    tdble      mu;
    tdble      I;         /* I = inertial moment of the wheel */
    tdble      curI;           /* Current inertia for the wheel (including transmission) */
    tdble  mfC;     /* Magic Formula C coeff */
    tdble  mfB;     /* Magic Formula B coeff */
    tdble  mfE;     /* Magic Formula E coeff */
    tdble  lfMax;     /* Load factor */
    tdble  lfMin;     /* Load factor */
    tdble  lfK;     /* Load factor */
    tdble  opLoad;       /* Operating load */
    tdble  mass;       /* total wheel mass (incl. brake) (unsprung mass) */
    tdble  camber;       /* camber, negative toward exterior on both sides */
    tdble  pressure;   /* initial tire pressure, environment temperature */
    tdble   rel_vel;    /* relative velocity - used for realstic suspension movement*/
    tdble  tirewidth; /* width of tire, used for surface property blending */
 
    tDynAxis    in;
    tDynAxis    feedBack;
 
    tdble  preFn, preFt;
    
    // Additional parameters for the tire wear model
    tdble treadMass;              // Initial mass of the tread
    tdble baseMass;                    // Mass of the tire minus the tread
    tdble treadThinkness;            // Thinkness of the initial tread (brand new tire)
    tdble tireGasMass;              // Mass of the gas in the tire (constant)
    tdble tireConvectionSurface;  // Surface area regarding the convection model
    tdble initialTemperature;        // Initial temperature of the tire (initial pressure, p0/T0=constant)
    tdble hysteresisFactor;            // Factor to adjust the hysteresis (model fitting), usually close to 1.0.
    tdble wearFactor;                // Factor to adjust the wear (model fitting), usually close to 1.0.
    tdble idealTemperature;            // Ideal tire temperature for best grip.
    
    // Dynamic Tire properties (temp, wear, etc.)
    tdble currentPressure;          // current tire pressure considering temperature
    tdble currentTemperature;        // current temperature
    double currentWear;              // [0..1], 1 means totally worn (tread thickness 0)
    tdble currentGraining;          // [0..1], 1 means totally grained
    tdble currentGripFactor;      // [0..1], 1 means best grip
    
    tdble tireSlip;                    // Slip of the tire from tire model calculation
    tdble tireZForce;                // Force on tire
    
} tWheel;
 
    
 
#endif /* _WHEEL_H__ */