git.gag.com Git - debian/openrocket/blob - src/net/sf/openrocket/simulation/RK4SimulationStepper.java

   1 package net.sf.openrocket.simulation;
   2
   3 import java.util.Arrays;
   4 import java.util.Random;
   5
   6 import net.sf.openrocket.aerodynamics.AerodynamicForces;
   7 import net.sf.openrocket.aerodynamics.FlightConditions;
   8 import net.sf.openrocket.aerodynamics.WarningSet;
   9 import net.sf.openrocket.logging.LogHelper;
  10 import net.sf.openrocket.models.atmosphere.AtmosphericConditions;
  11 import net.sf.openrocket.simulation.exception.SimulationCalculationException;
  12 import net.sf.openrocket.simulation.exception.SimulationException;
  13 import net.sf.openrocket.simulation.listeners.SimulationListenerHelper;
  14 import net.sf.openrocket.startup.Application;
  15 import net.sf.openrocket.util.Coordinate;
  16 import net.sf.openrocket.util.GeodeticComputationStrategy;
  17 import net.sf.openrocket.util.MathUtil;
  18 import net.sf.openrocket.util.Quaternion;
  19 import net.sf.openrocket.util.Rotation2D;
  20 import net.sf.openrocket.util.WorldCoordinate;
  21
  22 public class RK4SimulationStepper extends AbstractSimulationStepper {
  23
  24         private static final LogHelper log = Application.getLogger();
  25
  26         /** Random value with which to XOR the random seed value */
  27         private static final int SEED_RANDOMIZATION = 0x23E3A01F;
  28
  29
  30         /**
  31          * A recommended reasonably accurate time step.
  32          */
  33         public static final double RECOMMENDED_TIME_STEP = 0.05;
  34
  35         /**
  36          * A recommended maximum angle step value.
  37          */
  38         public static final double RECOMMENDED_ANGLE_STEP = 3 * Math.PI / 180;
  39
  40         /**
  41          * A random amount that is added to pitch and yaw coefficients, plus or minus.
  42          */
  43         public static final double PITCH_YAW_RANDOM = 0.0005;
  44
  45         /**
  46          * Maximum roll step allowed.  This is selected as an uneven division of the full
  47          * circle so that the simulation will sample the most wind directions
  48          */
  49         private static final double MAX_ROLL_STEP_ANGLE = 2 * 28.32 * Math.PI / 180;
  50         //      private static final double MAX_ROLL_STEP_ANGLE = 8.32 * Math.PI/180;
  51
  52         private static final double MAX_ROLL_RATE_CHANGE = 2 * Math.PI / 180;
  53         private static final double MAX_PITCH_CHANGE = 4 * Math.PI / 180;
  54
  55         private static final double MIN_TIME_STEP = 0.001;
  56
  57
  58         private Random random;
  59
  60
  61
  62
  63         @Override
  64         public RK4SimulationStatus initialize(SimulationStatus original) {
  65
  66                 RK4SimulationStatus status = new RK4SimulationStatus();
  67
  68                 status.copyFrom(original);
  69
  70                 SimulationConditions sim = original.getSimulationConditions();
  71
  72                 status.setLaunchRodDirection(new Coordinate(
  73                                 Math.sin(sim.getLaunchRodAngle()) * Math.cos(sim.getLaunchRodDirection()),
  74                                 Math.sin(sim.getLaunchRodAngle()) * Math.sin(sim.getLaunchRodDirection()),
  75                                 Math.cos(sim.getLaunchRodAngle())
  76                                 ));
  77
  78                 this.random = new Random(original.getSimulationConditions().getRandomSeed() ^ SEED_RANDOMIZATION);
  79
  80                 return status;
  81         }
  82
  83
  84
  85
  86         @Override
  87         public void step(SimulationStatus simulationStatus, double maxTimeStep) throws SimulationException {
  88
  89                 RK4SimulationStatus status = (RK4SimulationStatus) simulationStatus;
  90                 DataStore store = new DataStore();
  91
  92                 ////////  Perform RK4 integration:  ////////
  93
  94                 RK4SimulationStatus status2;
  95                 RK4Parameters k1, k2, k3, k4;
  96
  97                 /*
  98                  * Start with previous time step which is used to compute the initial thrust estimate.
  99                  * Don't make it longer than maxTimeStep, but at least MIN_TIME_STEP.
 100                  */
 101                 store.timestep = status.getPreviousTimeStep();
 102                 store.timestep = MathUtil.max(MathUtil.min(store.timestep, maxTimeStep), MIN_TIME_STEP);
 103                 checkNaN(store.timestep);
 104
 105                 /*
 106                  * Compute the initial thrust estimate.  This is used for the first time step computation.
 107                  */
 108                 store.thrustForce = calculateThrust(status, store.timestep, status.getPreviousAcceleration(),
 109                                 status.getPreviousAtmosphericConditions(), false);
 110
 111
 112                 /*
 113                  * Perform RK4 integration.  Decide the time step length after the first step.
 114                  */
 115
 116                 //// First position, k1 = f(t, y)
 117
 118                 k1 = computeParameters(status, store);
 119
 120                 /*
 121                  * Select the actual time step to use.  It is the minimum of the following:
 122                  *  dt[0]:  the user-specified time step (or 1/5th of it if still on the launch rod)
 123                  *  dt[1]:  the value of maxTimeStep
 124                  *  dt[2]:  the maximum pitch step angle limit
 125                  *  dt[3]:  the maximum roll step angle limit
 126                  *  dt[4]:  the maximum roll rate change limit
 127                  *  dt[5]:  the maximum pitch change limit
 128                  *  dt[6]:  1/10th of the launch rod length if still on the launch rod
 129                  *  dt[7]:  1.50 times the previous time step
 130                  *
 131                  * The limits #5 and #6 are required since near the steady-state roll rate the roll rate
 132                  * may oscillate significantly even between the sub-steps of the RK4 integration.
 133                  *
 134                  * The step is still at least 1/20th of the user-selected time step.
 135                  */
 136                 double[] dt = new double[8];
 137                 Arrays.fill(dt, Double.MAX_VALUE);
 138
 139                 dt[0] = status.getSimulationConditions().getTimeStep();
 140                 dt[1] = maxTimeStep;
 141                 dt[2] = status.getSimulationConditions().getMaximumAngleStep() / store.lateralPitchRate;
 142                 dt[3] = Math.abs(MAX_ROLL_STEP_ANGLE / store.flightConditions.getRollRate());
 143                 dt[4] = Math.abs(MAX_ROLL_RATE_CHANGE / store.rollAcceleration);
 144                 dt[5] = Math.abs(MAX_PITCH_CHANGE / store.lateralPitchAcceleration);
 145                 if (!status.isLaunchRodCleared()) {
 146                         dt[0] /= 5.0;
 147                         dt[6] = status.getSimulationConditions().getLaunchRodLength() / k1.v.length() / 10;
 148                 }
 149                 dt[7] = 1.5 * status.getPreviousTimeStep();
 150
 151                 store.timestep = Double.MAX_VALUE;
 152                 int limitingValue = -1;
 153                 for (int i = 0; i < dt.length; i++) {
 154                         if (dt[i] < store.timestep) {
 155                                 store.timestep = dt[i];
 156                                 limitingValue = i;
 157                         }
 158                 }
 159
 160                 double minTimeStep = status.getSimulationConditions().getTimeStep() / 20;
 161                 if (store.timestep < minTimeStep) {
 162                         log.verbose("Too small time step " + store.timestep + " (limiting factor " + limitingValue + "), using " +
 163                                         minTimeStep + " instead.");
 164                         store.timestep = minTimeStep;
 165                 } else {
 166                         log.verbose("Selected time step " + store.timestep + " (limiting factor " + limitingValue + ")");
 167                 }
 168                 checkNaN(store.timestep);
 169
 170                 /*
 171                  * Compute the correct thrust for this time step.  If the original thrust estimate differs more
 172                  * than 10% from the true value then recompute the RK4 step 1.  The 10% error in step 1 is
 173                  * diminished by it affecting only 1/6th of the total, so it's an acceptable error.
 174                  */
 175                 double thrustEstimate = store.thrustForce;
 176                 store.thrustForce = calculateThrust(status, store.timestep, store.longitudinalAcceleration,
 177                                 store.atmosphericConditions, true);
 178                 double thrustDiff = Math.abs(store.thrustForce - thrustEstimate);
 179                 // Log if difference over 1%, recompute if over 10%
 180                 if (thrustDiff > 0.01 * thrustEstimate) {
 181                         if (thrustDiff > 0.1 * thrustEstimate + 0.001) {
 182                                 log.debug("Thrust estimate differs from correct value by " +
 183                                                 (Math.rint(1000 * (thrustDiff + 0.000001) / thrustEstimate) / 10.0) + "%," +
 184                                                 " estimate=" + thrustEstimate +
 185                                                 " correct=" + store.thrustForce +
 186                                                 " timestep=" + store.timestep +
 187                                                 ", recomputing k1 parameters");
 188                                 k1 = computeParameters(status, store);
 189                         } else {
 190                                 log.verbose("Thrust estimate differs from correct value by " +
 191                                                 (Math.rint(1000 * (thrustDiff + 0.000001) / thrustEstimate) / 10.0) + "%," +
 192                                                 " estimate=" + thrustEstimate +
 193                                                 " correct=" + store.thrustForce +
 194                                                 " timestep=" + store.timestep +
 195                                                 ", error acceptable");
 196                         }
 197                 }
 198
 199                 // Store data
 200                 // TODO: MEDIUM: Store acceleration etc of entire RK4 step, store should be cloned or something...
 201                 storeData(status, store);
 202
 203
 204                 //// Second position, k2 = f(t + h/2, y + k1*h/2)
 205
 206                 status2 = status.clone();
 207                 status2.setSimulationTime(status.getSimulationTime() + store.timestep / 2);
 208                 status2.setRocketPosition(status.getRocketPosition().add(k1.v.multiply(store.timestep / 2)));
 209                 status2.setRocketVelocity(status.getRocketVelocity().add(k1.a.multiply(store.timestep / 2)));
 210                 status2.setRocketOrientationQuaternion(status.getRocketOrientationQuaternion().multiplyLeft(Quaternion.rotation(k1.rv.multiply(store.timestep / 2))));
 211                 status2.setRocketRotationVelocity(status.getRocketRotationVelocity().add(k1.ra.multiply(store.timestep / 2)));
 212
 213                 k2 = computeParameters(status2, store);
 214
 215
 216                 //// Third position, k3 = f(t + h/2, y + k2*h/2)
 217
 218                 status2 = status.clone();
 219                 status2.setSimulationTime(status.getSimulationTime() + store.timestep / 2);
 220                 status2.setRocketPosition(status.getRocketPosition().add(k2.v.multiply(store.timestep / 2)));
 221                 status2.setRocketVelocity(status.getRocketVelocity().add(k2.a.multiply(store.timestep / 2)));
 222                 status2.setRocketOrientationQuaternion(status2.getRocketOrientationQuaternion().multiplyLeft(Quaternion.rotation(k2.rv.multiply(store.timestep / 2))));
 223                 status2.setRocketRotationVelocity(status.getRocketRotationVelocity().add(k2.ra.multiply(store.timestep / 2)));
 224
 225                 k3 = computeParameters(status2, store);
 226
 227
 228                 //// Fourth position, k4 = f(t + h, y + k3*h)
 229
 230                 status2 = status.clone();
 231                 status2.setSimulationTime(status.getSimulationTime() + store.timestep);
 232                 status2.setRocketPosition(status.getRocketPosition().add(k3.v.multiply(store.timestep)));
 233                 status2.setRocketVelocity(status.getRocketVelocity().add(k3.a.multiply(store.timestep)));
 234                 status2.setRocketOrientationQuaternion(status2.getRocketOrientationQuaternion().multiplyLeft(Quaternion.rotation(k3.rv.multiply(store.timestep))));
 235                 status2.setRocketRotationVelocity(status.getRocketRotationVelocity().add(k3.ra.multiply(store.timestep)));
 236
 237                 k4 = computeParameters(status2, store);
 238
 239
 240                 //// Sum all together,  y(n+1) = y(n) + h*(k1 + 2*k2 + 2*k3 + k4)/6
 241
 242
 243
 244                 Coordinate deltaV, deltaP, deltaR, deltaO;
 245                 deltaV = k2.a.add(k3.a).multiply(2).add(k1.a).add(k4.a).multiply(store.timestep / 6);
 246                 deltaP = k2.v.add(k3.v).multiply(2).add(k1.v).add(k4.v).multiply(store.timestep / 6);
 247                 deltaR = k2.ra.add(k3.ra).multiply(2).add(k1.ra).add(k4.ra).multiply(store.timestep / 6);
 248                 deltaO = k2.rv.add(k3.rv).multiply(2).add(k1.rv).add(k4.rv).multiply(store.timestep / 6);
 249
 250
 251
 252                 status.setRocketVelocity(status.getRocketVelocity().add(deltaV));
 253                 status.setRocketPosition(status.getRocketPosition().add(deltaP));
 254                 status.setRocketRotationVelocity(status.getRocketRotationVelocity().add(deltaR));
 255                 status.setRocketOrientationQuaternion(status.getRocketOrientationQuaternion().multiplyLeft(Quaternion.rotation(deltaO)).normalizeIfNecessary());
 256
 257                 WorldCoordinate w = status.getSimulationConditions().getLaunchSite();
 258                 w = status.getSimulationConditions().getGeodeticComputation().addCoordinate(w, status.getRocketPosition());
 259                 status.setRocketWorldPosition(w);
 260
 261                 status.setSimulationTime(status.getSimulationTime() + store.timestep);
 262
 263                 status.setPreviousTimeStep(store.timestep);
 264
 265                 // Verify that values don't run out of range
 266                 if (status.getRocketVelocity().length2() > 1e18 ||
 267                                 status.getRocketPosition().length2() > 1e18 ||
 268                                 status.getRocketRotationVelocity().length2() > 1e18) {
 269                         throw new SimulationCalculationException("Simulation values exceeded limits");
 270                 }
 271         }
 272
 273
 274
 275
 276
 277         private RK4Parameters computeParameters(RK4SimulationStatus status, DataStore dataStore)
 278                         throws SimulationException {
 279                 RK4Parameters params = new RK4Parameters();
 280
 281                 //              if (dataStore == null) {
 282                 //                      dataStore = new DataStore();
 283                 //              }
 284
 285                 calculateAcceleration(status, dataStore);
 286                 params.a = dataStore.linearAcceleration;
 287                 params.ra = dataStore.angularAcceleration;
 288                 params.v = status.getRocketVelocity();
 289                 params.rv = status.getRocketRotationVelocity();
 290
 291                 checkNaN(params.a);
 292                 checkNaN(params.ra);
 293                 checkNaN(params.v);
 294                 checkNaN(params.rv);
 295
 296                 return params;
 297         }
 298
 299
 300
 301
 302
 303         /**
 304          * Calculate the linear and angular acceleration at the given status.  The results
 305          * are stored in the fields {@link #linearAcceleration} and {@link #angularAcceleration}.
 306          *
 307          * @param status   the status of the rocket.
 308          * @throws SimulationException
 309          */
 310         private void calculateAcceleration(RK4SimulationStatus status, DataStore store) throws SimulationException {
 311
 312                 // Call pre-listeners
 313                 store.accelerationData = SimulationListenerHelper.firePreAccelerationCalculation(status);
 314                 if (store.accelerationData != null) {
 315                         return;
 316                 }
 317
 318                 // Compute the forces affecting the rocket
 319                 calculateForces(status, store);
 320
 321                 // Calculate mass data
 322                 store.massData = calculateMassData(status);
 323
 324
 325                 // Calculate the forces from the aerodynamic coefficients
 326
 327                 double dynP = (0.5 * store.flightConditions.getAtmosphericConditions().getDensity() *
 328                                         MathUtil.pow2(store.flightConditions.getVelocity()));
 329                 double refArea = store.flightConditions.getRefArea();
 330                 double refLength = store.flightConditions.getRefLength();
 331
 332
 333                 // Linear forces in rocket coordinates
 334                 store.dragForce = store.forces.getCaxial() * dynP * refArea;
 335                 double fN = store.forces.getCN() * dynP * refArea;
 336                 double fSide = store.forces.getCside() * dynP * refArea;
 337
 338                 double forceZ = store.thrustForce - store.dragForce;
 339
 340                 store.linearAcceleration = new Coordinate(-fN / store.massData.getCG().weight,
 341                                         -fSide / store.massData.getCG().weight,
 342                                         forceZ / store.massData.getCG().weight);
 343
 344                 store.linearAcceleration = store.thetaRotation.rotateZ(store.linearAcceleration);
 345
 346                 // Convert into rocket world coordinates
 347                 store.linearAcceleration = status.getRocketOrientationQuaternion().rotate(store.linearAcceleration);
 348
 349                 // add effect of gravity
 350                 store.gravity = modelGravity(status);
 351                 store.linearAcceleration = store.linearAcceleration.sub(0, 0, store.gravity);
 352
 353                 // add effect of Coriolis acceleration
 354                 store.coriolisAcceleration = status.getSimulationConditions().getGeodeticComputation()
 355                                 .getCoriolisAcceleration(status.getRocketWorldPosition(), status.getRocketVelocity());
 356                 store.linearAcceleration = store.linearAcceleration.add(store.coriolisAcceleration);
 357
 358                 // If still on the launch rod, project acceleration onto launch rod direction and
 359                 // set angular acceleration to zero.
 360                 if (!status.isLaunchRodCleared()) {
 361
 362                         store.linearAcceleration = status.getLaunchRodDirection().multiply(
 363                                                 store.linearAcceleration.dot(status.getLaunchRodDirection()));
 364                         store.angularAcceleration = Coordinate.NUL;
 365                         store.rollAcceleration = 0;
 366                         store.lateralPitchAcceleration = 0;
 367
 368                 } else {
 369
 370                         // Shift moments to CG
 371                         double Cm = store.forces.getCm() - store.forces.getCN() * store.massData.getCG().x / refLength;
 372                         double Cyaw = store.forces.getCyaw() - store.forces.getCside() * store.massData.getCG().x / refLength;
 373
 374                         // Compute moments
 375                         double momX = -Cyaw * dynP * refArea * refLength;
 376                         double momY = Cm * dynP * refArea * refLength;
 377                         double momZ = store.forces.getCroll() * dynP * refArea * refLength;
 378
 379                         // Compute acceleration in rocket coordinates
 380                         store.angularAcceleration = new Coordinate(momX / store.massData.getLongitudinalInertia(),
 381                                                 momY / store.massData.getLongitudinalInertia(),
 382                                                 momZ / store.massData.getRotationalInertia());
 383
 384                         store.rollAcceleration = store.angularAcceleration.z;
 385                         // TODO: LOW: This should be hypot, but does it matter?
 386                         store.lateralPitchAcceleration = MathUtil.max(Math.abs(store.angularAcceleration.x),
 387                                                 Math.abs(store.angularAcceleration.y));
 388
 389                         store.angularAcceleration = store.thetaRotation.rotateZ(store.angularAcceleration);
 390
 391                         // Convert to world coordinates
 392                         store.angularAcceleration = status.getRocketOrientationQuaternion().rotate(store.angularAcceleration);
 393
 394                 }
 395
 396                 // Call post-listeners
 397                 store.accelerationData = SimulationListenerHelper.firePostAccelerationCalculation(status, store.accelerationData);
 398         }
 399
 400
 401         /**
 402          * Calculate the aerodynamic forces into the data store.  This method also handles
 403          * whether to include aerodynamic computation warnings or not.
 404          */
 405         private void calculateForces(RK4SimulationStatus status, DataStore store) throws SimulationException {
 406
 407                 // Call pre-listeners
 408                 store.forces = SimulationListenerHelper.firePreAerodynamicCalculation(status);
 409                 if (store.forces != null) {
 410                         return;
 411                 }
 412
 413                 // Compute flight conditions
 414                 calculateFlightConditions(status, store);
 415
 416                 /*
 417                  * Check whether to store warnings or not.  Warnings are ignored when on the
 418                  * launch rod or 0.25 seconds after departure, and when the velocity has dropped
 419                  * below 20% of the max. velocity.
 420                  */
 421                 WarningSet warnings = status.getWarnings();
 422                 status.setMaxZVelocity(MathUtil.max(status.getMaxZVelocity(), status.getRocketVelocity().z));
 423
 424                 if (!status.isLaunchRodCleared()) {
 425                         warnings = null;
 426                 } else {
 427                         if (status.getRocketVelocity().z < 0.2 * status.getMaxZVelocity())
 428                                 warnings = null;
 429                         if (status.getStartWarningTime() < 0)
 430                                 status.setStartWarningTime(status.getSimulationTime() + 0.25);
 431                 }
 432                 if (status.getSimulationTime() < status.getStartWarningTime())
 433                         warnings = null;
 434
 435
 436                 // Calculate aerodynamic forces
 437                 store.forces = status.getSimulationConditions().getAerodynamicCalculator()
 438                                 .getAerodynamicForces(status.getConfiguration(), store.flightConditions, warnings);
 439
 440
 441                 // Add very small randomization to yaw & pitch moments to prevent over-perfect flight
 442                 // TODO: HIGH: This should rather be performed as a listener
 443                 store.forces.setCm(store.forces.getCm() + (PITCH_YAW_RANDOM * 2 * (random.nextDouble() - 0.5)));
 444                 store.forces.setCyaw(store.forces.getCyaw() + (PITCH_YAW_RANDOM * 2 * (random.nextDouble() - 0.5)));
 445
 446
 447                 // Call post-listeners
 448                 store.forces = SimulationListenerHelper.firePostAerodynamicCalculation(status, store.forces);
 449         }
 450
 451
 452
 453         /**
 454          * Calculate and return the flight conditions for the current rocket status.
 455          * Listeners can override these if necessary.
 456          * <p>
 457          * Additionally the fields thetaRotation and lateralPitchRate are defined in
 458          * the data store, and can be used after calling this method.
 459          */
 460         private void calculateFlightConditions(RK4SimulationStatus status, DataStore store)
 461                         throws SimulationException {
 462
 463                 // Call pre listeners, allow complete override
 464                 store.flightConditions = SimulationListenerHelper.firePreFlightConditions(
 465                                 status);
 466                 if (store.flightConditions != null) {
 467                         // Compute the store values
 468                         store.thetaRotation = new Rotation2D(store.flightConditions.getTheta());
 469                         store.lateralPitchRate = Math.hypot(store.flightConditions.getPitchRate(), store.flightConditions.getYawRate());
 470                         return;
 471                 }
 472
 473
 474
 475                 //// Atmospheric conditions
 476                 AtmosphericConditions atmosphere = modelAtmosphericConditions(status);
 477                 store.flightConditions = new FlightConditions(status.getConfiguration());
 478                 store.flightConditions.setAtmosphericConditions(atmosphere);
 479
 480
 481                 //// Local wind speed and direction
 482                 Coordinate windSpeed = modelWindVelocity(status);
 483                 Coordinate airSpeed = status.getRocketVelocity().add(windSpeed);
 484                 airSpeed = status.getRocketOrientationQuaternion().invRotate(airSpeed);
 485
 486
 487                 // Lateral direction:
 488                 double len = MathUtil.hypot(airSpeed.x, airSpeed.y);
 489                 if (len > 0.0001) {
 490                         store.thetaRotation = new Rotation2D(airSpeed.y / len, airSpeed.x / len);
 491                         store.flightConditions.setTheta(Math.atan2(airSpeed.y, airSpeed.x));
 492                 } else {
 493                         store.thetaRotation = Rotation2D.ID;
 494                         store.flightConditions.setTheta(0);
 495                 }
 496
 497                 double velocity = airSpeed.length();
 498                 store.flightConditions.setVelocity(velocity);
 499                 if (velocity > 0.01) {
 500                         // aoa must be calculated from the monotonous cosine
 501                         // sine can be calculated by a simple division
 502                         store.flightConditions.setAOA(Math.acos(airSpeed.z / velocity), len / velocity);
 503                 } else {
 504                         store.flightConditions.setAOA(0);
 505                 }
 506
 507
 508                 // Roll, pitch and yaw rate
 509                 Coordinate rot = status.getRocketOrientationQuaternion().invRotate(status.getRocketRotationVelocity());
 510                 rot = store.thetaRotation.invRotateZ(rot);
 511
 512                 store.flightConditions.setRollRate(rot.z);
 513                 if (len < 0.001) {
 514                         store.flightConditions.setPitchRate(0);
 515                         store.flightConditions.setYawRate(0);
 516                         store.lateralPitchRate = 0;
 517                 } else {
 518                         store.flightConditions.setPitchRate(rot.y);
 519                         store.flightConditions.setYawRate(rot.x);
 520                         // TODO: LOW: set this as power of two?
 521                         store.lateralPitchRate = MathUtil.hypot(rot.x, rot.y);
 522                 }
 523
 524
 525                 // Call post listeners
 526                 FlightConditions c = SimulationListenerHelper.firePostFlightConditions(
 527                                 status, store.flightConditions);
 528                 if (c != store.flightConditions) {
 529                         // Listeners changed the values, recalculate data store
 530                         store.flightConditions = c;
 531                         store.thetaRotation = new Rotation2D(store.flightConditions.getTheta());
 532                         store.lateralPitchRate = Math.hypot(store.flightConditions.getPitchRate(), store.flightConditions.getYawRate());
 533                 }
 534
 535         }
 536
 537
 538
 539         private void storeData(RK4SimulationStatus status, DataStore store) {
 540
 541                 FlightDataBranch data = status.getFlightData();
 542                 boolean extra = status.getSimulationConditions().isCalculateExtras();
 543
 544                 data.addPoint();
 545                 data.setValue(FlightDataType.TYPE_TIME, status.getSimulationTime());
 546                 data.setValue(FlightDataType.TYPE_ALTITUDE, status.getRocketPosition().z);
 547                 data.setValue(FlightDataType.TYPE_POSITION_X, status.getRocketPosition().x);
 548                 data.setValue(FlightDataType.TYPE_POSITION_Y, status.getRocketPosition().y);
 549
 550                 if (status.getSimulationConditions().getGeodeticComputation() != GeodeticComputationStrategy.NONE) {
 551                         data.setValue(FlightDataType.TYPE_LATITUDE, status.getRocketWorldPosition().getLatitudeRad());
 552                         data.setValue(FlightDataType.TYPE_LONGITUDE, status.getRocketWorldPosition().getLongitudeRad());
 553                         data.setValue(FlightDataType.TYPE_CORIOLIS_ACCELERATION, store.coriolisAcceleration.length());
 554                 }
 555
 556                 if (extra) {
 557                         data.setValue(FlightDataType.TYPE_POSITION_XY,
 558                                         MathUtil.hypot(status.getRocketPosition().x, status.getRocketPosition().y));
 559                         data.setValue(FlightDataType.TYPE_POSITION_DIRECTION,
 560                                         Math.atan2(status.getRocketPosition().y, status.getRocketPosition().x));
 561
 562                         data.setValue(FlightDataType.TYPE_VELOCITY_XY,
 563                                         MathUtil.hypot(status.getRocketVelocity().x, status.getRocketVelocity().y));
 564
 565                         if (store.linearAcceleration != null) {
 566                                 data.setValue(FlightDataType.TYPE_ACCELERATION_XY,
 567                                                 MathUtil.hypot(store.linearAcceleration.x, store.linearAcceleration.y));
 568
 569                                 data.setValue(FlightDataType.TYPE_ACCELERATION_TOTAL, store.linearAcceleration.length());
 570                         }
 571
 572                         if (store.flightConditions != null) {
 573                                 double Re = (store.flightConditions.getVelocity() *
 574                                                 status.getConfiguration().getLength() /
 575                                                 store.flightConditions.getAtmosphericConditions().getKinematicViscosity());
 576                                 data.setValue(FlightDataType.TYPE_REYNOLDS_NUMBER, Re);
 577                         }
 578                 }
 579
 580                 data.setValue(FlightDataType.TYPE_VELOCITY_Z, status.getRocketVelocity().z);
 581                 if (store.linearAcceleration != null) {
 582                         data.setValue(FlightDataType.TYPE_ACCELERATION_Z, store.linearAcceleration.z);
 583                 }
 584
 585                 if (store.flightConditions != null) {
 586                         data.setValue(FlightDataType.TYPE_VELOCITY_TOTAL, status.getRocketVelocity().length());
 587                         data.setValue(FlightDataType.TYPE_MACH_NUMBER, store.flightConditions.getMach());
 588                 }
 589
 590                 if (store.massData != null) {
 591                         data.setValue(FlightDataType.TYPE_CG_LOCATION, store.massData.getCG().x);
 592                 }
 593                 if (status.isLaunchRodCleared()) {
 594                         // Don't include CP and stability with huge launch AOA
 595                         if (store.forces != null) {
 596                                 data.setValue(FlightDataType.TYPE_CP_LOCATION, store.forces.getCP().x);
 597                         }
 598                         if (store.forces != null && store.flightConditions != null && store.massData != null) {
 599                                 data.setValue(FlightDataType.TYPE_STABILITY,
 600                                                 (store.forces.getCP().x - store.massData.getCG().x) / store.flightConditions.getRefLength());
 601                         }
 602                 }
 603                 if (store.massData != null) {
 604                         data.setValue(FlightDataType.TYPE_MASS, store.massData.getCG().weight);
 605                         data.setValue(FlightDataType.TYPE_LONGITUDINAL_INERTIA, store.massData.getLongitudinalInertia());
 606                         data.setValue(FlightDataType.TYPE_ROTATIONAL_INERTIA, store.massData.getRotationalInertia());
 607                 }
 608
 609                 data.setValue(FlightDataType.TYPE_THRUST_FORCE, store.thrustForce);
 610                 data.setValue(FlightDataType.TYPE_DRAG_FORCE, store.dragForce);
 611
 612                 if (status.isLaunchRodCleared() && store.forces != null) {
 613                         if (store.massData != null && store.flightConditions != null) {
 614                                 data.setValue(FlightDataType.TYPE_PITCH_MOMENT_COEFF,
 615                                                 store.forces.getCm() - store.forces.getCN() * store.massData.getCG().x / store.flightConditions.getRefLength());
 616                                 data.setValue(FlightDataType.TYPE_YAW_MOMENT_COEFF,
 617                                                 store.forces.getCyaw() - store.forces.getCside() * store.massData.getCG().x / store.flightConditions.getRefLength());
 618                         }
 619                         data.setValue(FlightDataType.TYPE_NORMAL_FORCE_COEFF, store.forces.getCN());
 620                         data.setValue(FlightDataType.TYPE_SIDE_FORCE_COEFF, store.forces.getCside());
 621                         data.setValue(FlightDataType.TYPE_ROLL_MOMENT_COEFF, store.forces.getCroll());
 622                         data.setValue(FlightDataType.TYPE_ROLL_FORCING_COEFF, store.forces.getCrollForce());
 623                         data.setValue(FlightDataType.TYPE_ROLL_DAMPING_COEFF, store.forces.getCrollDamp());
 624                         data.setValue(FlightDataType.TYPE_PITCH_DAMPING_MOMENT_COEFF,
 625                                         store.forces.getPitchDampingMoment());
 626                 }
 627
 628                 if (store.forces != null) {
 629                         data.setValue(FlightDataType.TYPE_DRAG_COEFF, store.forces.getCD());
 630                         data.setValue(FlightDataType.TYPE_AXIAL_DRAG_COEFF, store.forces.getCaxial());
 631                         data.setValue(FlightDataType.TYPE_FRICTION_DRAG_COEFF, store.forces.getFrictionCD());
 632                         data.setValue(FlightDataType.TYPE_PRESSURE_DRAG_COEFF, store.forces.getPressureCD());
 633                         data.setValue(FlightDataType.TYPE_BASE_DRAG_COEFF, store.forces.getBaseCD());
 634                 }
 635
 636                 if (store.flightConditions != null) {
 637                         data.setValue(FlightDataType.TYPE_REFERENCE_LENGTH, store.flightConditions.getRefLength());
 638                         data.setValue(FlightDataType.TYPE_REFERENCE_AREA, store.flightConditions.getRefArea());
 639
 640                         data.setValue(FlightDataType.TYPE_PITCH_RATE, store.flightConditions.getPitchRate());
 641                         data.setValue(FlightDataType.TYPE_YAW_RATE, store.flightConditions.getYawRate());
 642                         data.setValue(FlightDataType.TYPE_ROLL_RATE, store.flightConditions.getRollRate());
 643
 644                         data.setValue(FlightDataType.TYPE_AOA, store.flightConditions.getAOA());
 645                 }
 646
 647
 648                 if (extra) {
 649                         Coordinate c = status.getRocketOrientationQuaternion().rotateZ();
 650                         double theta = Math.atan2(c.z, MathUtil.hypot(c.x, c.y));
 651                         double phi = Math.atan2(c.y, c.x);
 652                         if (phi < -(Math.PI - 0.0001))
 653                                 phi = Math.PI;
 654                         data.setValue(FlightDataType.TYPE_ORIENTATION_THETA, theta);
 655                         data.setValue(FlightDataType.TYPE_ORIENTATION_PHI, phi);
 656                 }
 657
 658                 data.setValue(FlightDataType.TYPE_WIND_VELOCITY, store.windSpeed);
 659
 660                 if (store.flightConditions != null) {
 661                         data.setValue(FlightDataType.TYPE_AIR_TEMPERATURE,
 662                                         store.flightConditions.getAtmosphericConditions().getTemperature());
 663                         data.setValue(FlightDataType.TYPE_AIR_PRESSURE,
 664                                         store.flightConditions.getAtmosphericConditions().getPressure());
 665                         data.setValue(FlightDataType.TYPE_SPEED_OF_SOUND,
 666                                         store.flightConditions.getAtmosphericConditions().getMachSpeed());
 667                 }
 668
 669
 670                 data.setValue(FlightDataType.TYPE_TIME_STEP, store.timestep);
 671                 data.setValue(FlightDataType.TYPE_COMPUTATION_TIME,
 672                                 (System.nanoTime() - status.getSimulationStartWallTime()) / 1000000000.0);
 673         }
 674
 675
 676
 677
 678         private static class RK4Parameters {
 679                 /** Linear acceleration */
 680                 public Coordinate a;
 681                 /** Linear velocity */
 682                 public Coordinate v;
 683                 /** Rotational acceleration */
 684                 public Coordinate ra;
 685                 /** Rotational velocity */
 686                 public Coordinate rv;
 687         }
 688
 689         private static class DataStore {
 690                 public double timestep = Double.NaN;
 691
 692                 public AccelerationData accelerationData;
 693
 694                 public AtmosphericConditions atmosphericConditions;
 695
 696                 public FlightConditions flightConditions;
 697
 698                 public double longitudinalAcceleration = Double.NaN;
 699
 700                 public MassData massData;
 701
 702                 public Coordinate coriolisAcceleration;
 703
 704                 public Coordinate linearAcceleration;
 705                 public Coordinate angularAcceleration;
 706
 707                 // set by calculateFlightConditions and calculateAcceleration:
 708                 public AerodynamicForces forces;
 709                 public double windSpeed = Double.NaN;
 710                 public double gravity = Double.NaN;
 711                 public double thrustForce = Double.NaN;
 712                 public double dragForce = Double.NaN;
 713                 public double lateralPitchRate = Double.NaN;
 714
 715                 public double rollAcceleration = Double.NaN;
 716                 public double lateralPitchAcceleration = Double.NaN;
 717
 718                 public Rotation2D thetaRotation;
 719
 720         }
 721
 722 }