Merge pull request #181 from bkuker/tumble

Changes to Tumble Transition & Tumble Bug Fix

core/resources/l10n/messages.properties

@@ -1539,6 +1539,8 @@ Warning.PARALLEL_FINS = Too many parallel fins
 Warning.SUPERSONIC = Body calculations may not be entirely accurate at supersonic speeds.
 Warning.RECOVERY_LAUNCH_ROD = Recovery device device deployed while on the launch guide.
 Warning.RECOVERY_HIGH_SPEED = Recovery device deployment at high speed
+Warning.TUMBLE_UNDER_THRUST = Stage began to tumble under thrust.
+Warning.TUMBLE_BEFORE_APOGEE = Sustainer became unstable before apogee.
 
 
 ! Scale dialog

core/src/net/sf/openrocket/aerodynamics/Warning.java

@@ -325,4 +325,10 @@ public abstract class Warning {
 	
 	public static final Warning RECOVERY_LAUNCH_ROD =
 			new Other(trans.get("Warning.RECOVERY_LAUNCH_ROD"));
+	
+	public static final Warning TUMBLE_UNDER_THRUST =
+			new Other(trans.get("Warning.TUMBLE_UNDER_THRUST"));
+	
+	public static final Warning TUMBLE_BEFORE_APOGEE =
+			new Other(trans.get("Warning.TUMBLE_BEFORE_APOGEE"));
 }

core/src/net/sf/openrocket/simulation/BasicEventSimulationEngine.java

@@ -42,10 +42,14 @@ public class BasicEventSimulationEngine implements SimulationEngine {
 	private SimulationStepper landingStepper = new BasicLandingStepper();
 	private SimulationStepper tumbleStepper = new BasicTumbleStepper();
 	
-	// Constant holding 10 degress in radians.  This is the AOA condition
+	// Constant holding 20 degress in radians.  This is the AOA condition
 	// necessary to transistion to tumbling.
 	private final static double AOA_TUMBLE_CONDITION = Math.PI / 9.0;
 	
+	// The thrust must be below this value for the transition to tumbling.
+	// TODO: this is an arbitrary value
+	private final static double THRUST_TUMBLE_CONDITION = 0.01;
+	
 	private SimulationStepper currentStepper;
 	
 	private SimulationStatus status;
@@ -202,18 +206,32 @@ public class BasicEventSimulationEngine implements SimulationEngine {
 				
 				// Check for Tumbling
 				// Conditions for transision are:
-				//  apogee reached
+				//  apogee reached (if sustainer stage)
 				// and is not already tumbling
 				// and not stable (cg > cp)
-				// and aoa > 30
+				// and aoa > AOA_TUMBLE_CONDITION threshold
+				// and thrust < THRUST_TUMBLE_CONDITION threshold
 				
-				if (status.isApogeeReached() && !status.isTumbling()) {
+				if (!status.isTumbling()) {
-					double cp = status.getFlightData().getLast(FlightDataType.TYPE_CP_LOCATION);
+					final double t = status.getFlightData().getLast(FlightDataType.TYPE_THRUST_FORCE);
-					double cg = status.getFlightData().getLast(FlightDataType.TYPE_CG_LOCATION);
+					final double cp = status.getFlightData().getLast(FlightDataType.TYPE_CP_LOCATION);
-					double aoa = status.getFlightData().getLast(FlightDataType.TYPE_AOA);
+					final double cg = status.getFlightData().getLast(FlightDataType.TYPE_CG_LOCATION);
-					if (cg > cp && aoa > AOA_TUMBLE_CONDITION) {
+					final double aoa = status.getFlightData().getLast(FlightDataType.TYPE_AOA);
-						addEvent(new FlightEvent(FlightEvent.Type.TUMBLE, status.getSimulationTime()));
+					
-						status.setTumbling(true);
+					final boolean wantToTumble = (cg > cp && aoa > AOA_TUMBLE_CONDITION);
+					
+					if (wantToTumble) {
+						final boolean tooMuchThrust = t > THRUST_TUMBLE_CONDITION;
+						final boolean isSustainer = status.getConfiguration().isStageActive(0);
+						final boolean notUntilApogee = isSustainer && !status.isApogeeReached();
+						if (tooMuchThrust) {
+							status.getWarnings().add(Warning.TUMBLE_UNDER_THRUST);
+						} else if (notUntilApogee) {
+							status.getWarnings().add(Warning.TUMBLE_BEFORE_APOGEE);
+						} else {
+							addEvent(new FlightEvent(FlightEvent.Type.TUMBLE, status.getSimulationTime()));
+							status.setTumbling(true);
+						}
 					}
 					
 				}

core/src/net/sf/openrocket/simulation/BasicTumbleStatus.java

@@ -18,19 +18,21 @@ public class BasicTumbleStatus extends SimulationStatus {
 	// offset the indexes so finEff[1] is the coefficient for one fin from the table in techdoc.pdf
 	private final static double[] finEff = { 0.0, 0.5, 1.0, 1.41, 1.81, 1.73, 1.90, 1.85 };
 	
-	private double drag;
+	private final double drag;
 	
 	public BasicTumbleStatus(Configuration configuration,
 			MotorInstanceConfiguration motorConfiguration,
 			SimulationConditions simulationConditions) {
 		super(configuration, motorConfiguration, simulationConditions);
-		computeTumbleDrag();
+		this.drag = computeTumbleDrag();
 	}
 	
 	public BasicTumbleStatus(SimulationStatus orig) {
 		super(orig);
 		if (orig instanceof BasicTumbleStatus) {
 			this.drag = ((BasicTumbleStatus) orig).drag;
+		} else {
+			this.drag = computeTumbleDrag();
 		}
 	}
 	
@@ -39,7 +41,7 @@ public class BasicTumbleStatus extends SimulationStatus {
 	}
 	
 	
-	public void computeTumbleDrag() {
+	private double computeTumbleDrag() {
 		
 		// Computed based on Sampo's experimentation as documented in the pdf.
 		
@@ -69,6 +71,6 @@ public class BasicTumbleStatus extends SimulationStatus {
 			}
 		}
 		
-		drag = (cDFin * aFins + cDBt * aBt);
+		return (cDFin * aFins + cDBt * aBt);
 	}
 }

swing/src/net/sf/openrocket/gui/plot/EventGraphics.java

@@ -39,6 +39,7 @@ public class EventGraphics {
 		EVENT_COLORS.put(FlightEvent.Type.RECOVERY_DEVICE_DEPLOYMENT, new Color(0, 0, 128));
 		EVENT_COLORS.put(FlightEvent.Type.GROUND_HIT, new Color(0, 0, 0));
 		EVENT_COLORS.put(FlightEvent.Type.SIMULATION_END, new Color(128, 0, 0));
+		EVENT_COLORS.put(FlightEvent.Type.TUMBLE, new Color(196, 0, 255));
 	}
 
 	private static final Map<FlightEvent.Type, Image> EVENT_IMAGES = new HashMap<FlightEvent.Type, Image>();