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