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