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