Merge pull request #577 from wolsen/issue-576

Fix ground hit velocity calculation

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

@@ -101,7 +101,7 @@ public class FlightData {
 		for (FlightDataBranch b : branches)
 			this.addBranch(b);
 		
-		calculateIntrestingValues();
+		calculateInterestingValues();
 	}
 	
 	
@@ -126,7 +126,7 @@ public class FlightData {
 		branches.add(branch);
 		
 		if (branches.size() == 1) {
-			calculateIntrestingValues();
+			calculateInterestingValues();
 		}
 	}
 	
@@ -185,7 +185,7 @@ public class FlightData {
 	 * Calculate the max. altitude/velocity/acceleration, time to apogee, flight time
 	 * and ground hit velocity.
 	 */
-	private void calculateIntrestingValues() {
+	private void calculateInterestingValues() {
 		if (branches.isEmpty())
 			return;
 		
@@ -195,13 +195,7 @@ public class FlightData {
 		maxMachNumber = branch.getMaximum(FlightDataType.TYPE_MACH_NUMBER);
 		
 		flightTime = branch.getLast(FlightDataType.TYPE_TIME);
-		if (branch.getLast(FlightDataType.TYPE_ALTITUDE) < 10) {
-			groundHitVelocity = branch.getLast(FlightDataType.TYPE_VELOCITY_TOTAL);
-		} else {
-			groundHitVelocity = Double.NaN;
-		}
 		
-
 		// Time to apogee
 		List<Double> time = branch.get(FlightDataType.TYPE_TIME);
 		List<Double> altitude = branch.get(FlightDataType.TYPE_ALTITUDE);
@@ -236,6 +230,10 @@ public class FlightData {
 				double t = event.getTime();
 				List<Double> velocity = branch.get(FlightDataType.TYPE_VELOCITY_TOTAL);
 				deploymentVelocity = MathUtil.interpolate( time, velocity, t);
+			} else if (event.getType() == FlightEvent.Type.GROUND_HIT) {
+				double t = event.getTime();
+				List<Double> velocity = branch.get(FlightDataType.TYPE_VELOCITY_TOTAL);
+				groundHitVelocity = MathUtil.interpolate( time,  velocity, t);
 			}
 		}
 		

core/test/net/sf/openrocket/simulation/TestFlightData.java

@@ -0,0 +1,285 @@
+package net.sf.openrocket.simulation;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertNotNull;
+import static org.junit.Assert.assertTrue;
+
+import org.junit.Test;
+
+import net.sf.openrocket.aerodynamics.WarningSet;
+
+/**
+ * Tests the FlightData object.
+ * 
+ * @author Billy Olsen
+ */
+public class TestFlightData {
+
+	/**
+	 * Test method for {@link net.sf.openrocket.simulation.FlightData#FlightData()}.
+	 */
+	@Test
+	public void testFlightData() {
+		FlightData data = new FlightData();
+		
+		WarningSet warnings = data.getWarningSet();
+		assertNotNull(warnings);
+		assertTrue(warnings.isEmpty());
+		
+		assertEquals(0, data.getBranchCount());
+		assertEquals(Double.NaN, data.getDeploymentVelocity(), 0.00);
+		assertEquals(Double.NaN, data.getFlightTime(), 0.00);
+		assertEquals(Double.NaN, data.getGroundHitVelocity(), 0.00);
+		assertEquals(Double.NaN, data.getLaunchRodVelocity(), 0.00);
+		assertEquals(Double.NaN, data.getMaxAcceleration(), 0.00);
+		assertEquals(Double.NaN, data.getMaxAltitude(), 0.00);
+		assertEquals(Double.NaN, data.getMaxMachNumber(), 0.00);
+		assertEquals(Double.NaN, data.getTimeToApogee(), 0.00);
+		
+	}
+	
+	/**
+	 * Tests flight data created from summary data.
+	 */
+	@Test
+	public void testFlightDataFromSummaryData() {
+		double deploymentVelocity = 14.8;
+		double flightTime = 69.1;
+		double groundHitVelocity = 3.4;
+		double launchRodVelocity = 17.5;
+		double maxAcceleration = 156.2;
+		double maxVelocity = 105.9;
+		double maxAltitude = 355.1;
+		double maxMachNumber = 0.31;
+		double timeToApogee = 7.96;
+		
+		FlightData data = new FlightData(maxAltitude, maxVelocity, maxAcceleration,
+				                         maxMachNumber, timeToApogee, flightTime,
+				                         groundHitVelocity, launchRodVelocity,
+				                         deploymentVelocity);
+		
+		WarningSet warnings = data.getWarningSet();
+		assertNotNull(warnings);
+		assertTrue(warnings.isEmpty());
+		
+		assertEquals(0, data.getBranchCount());
+		assertEquals(deploymentVelocity, data.getDeploymentVelocity(), 0.00);
+		assertEquals(flightTime, data.getFlightTime(), 0.00);
+		assertEquals(groundHitVelocity, data.getGroundHitVelocity(), 0.00);
+		assertEquals(launchRodVelocity, data.getLaunchRodVelocity(), 0.00);
+		assertEquals(maxAcceleration, data.getMaxAcceleration(), 0.00);
+		assertEquals(maxAltitude, data.getMaxAltitude(), 0.00);
+		assertEquals(maxMachNumber, data.getMaxMachNumber(), 0.00);
+		assertEquals(timeToApogee, data.getTimeToApogee(), 0.00);
+	}
+	
+	/**
+	 * Test method for {@link net.sf.openrocket.simulation.FlightData#FlightData(net.sf.openrocket.simulation.FlightDataBranch[])}.
+	 */
+	@Test
+	public void testFlightDataFlightDataBranchArray() {		
+		FlightData data = new FlightData(new FlightDataBranch("Test", FlightDataType.TYPE_TIME));
+		
+		WarningSet warnings = data.getWarningSet();
+		assertNotNull(warnings);
+		assertTrue(warnings.isEmpty());
+		
+		assertEquals(1, data.getBranchCount());
+		
+		data = new FlightData(new FlightDataBranch("Test 1", FlightDataType.TYPE_TIME),
+		                      new FlightDataBranch("Test 2", FlightDataType.TYPE_TIME));
+		
+		warnings = data.getWarningSet();
+		assertNotNull(warnings);
+		assertTrue(warnings.isEmpty());
+		
+		assertEquals(2, data.getBranchCount());
+	}
+	
+	private FlightDataBranch createFlightDataBranch(final String name, final FlightDataType dataType, final double[] values) {
+		final FlightDataBranch branch = new FlightDataBranch(name, dataType);
+		addDataPoints(branch, dataType, values);
+		return branch;
+	}
+	
+	private void addDataPoints(final FlightDataBranch branch, final FlightDataType dataType, final double[] values) {
+		for (int i=0; i < values.length; i++) {
+			branch.addPoint();
+			branch.setValue(dataType, values[i]);
+		}
+	}
+
+	/**
+	 * Test method for {@link net.sf.openrocket.simulation.FlightData#getMaxAltitude()}.
+	 */
+	@Test
+	public void testGetMaxAltitudeCalculated() {
+		final double[] altitudes = new double[] {
+				10.5,
+				37.771,
+				37.5,
+				5.1,
+				0.0
+			};
+		FlightDataBranch branch = 
+				createFlightDataBranch("Test Max Alt", FlightDataType.TYPE_ALTITUDE, altitudes);
+		
+		FlightData data = new FlightData(branch);
+
+		assertEquals(37.771, data.getMaxAltitude(), 0.000);
+	}
+	
+	/**
+	 * Test method for {@link net.sf.openrocket.simulation.FlightData#getMaxVelocity()}.
+	 */
+	@Test
+	public void testGetMaxVelocityCalculated() {
+		final double[] velocities = new double[] {
+				10.5,
+				23.7,
+				35.5,
+				30.1,
+				0.0
+			};
+		FlightDataBranch branch = 
+				createFlightDataBranch("Test Max Velocity", FlightDataType.TYPE_VELOCITY_TOTAL, velocities);
+		
+		FlightData data = new FlightData(branch);
+
+		assertEquals(35.5, data.getMaxVelocity(), 0.000);
+	}
+		
+	/**
+	 * Test method for {@link net.sf.openrocket.simulation.FlightData#getMaxMachNumber()}.
+	 */
+	@Test
+	public void testGetMaxMachNumberCalculated() {
+		final double[] machs = new double[] {
+				0.1,
+				0.2,
+				0.333,
+				0.3,
+				0.1
+			};
+		FlightDataBranch branch = 
+				createFlightDataBranch("Test Max Mach", FlightDataType.TYPE_MACH_NUMBER, machs);
+		
+		FlightData data = new FlightData(branch);
+
+		assertEquals(0.333, data.getMaxMachNumber(), 0.000);
+	}
+	
+	/**
+	 * Test method for {@link net.sf.openrocket.simulation.FlightData#getFlightTime()}.
+	 */
+	@Test
+	public void testGetFlightTime() {
+		final double[] times = new double[] {
+				1.0,
+				5.0,
+				15.0,
+				20.1,
+				30.2
+			};
+		FlightDataBranch branch =
+				createFlightDataBranch("Test Flight Time", FlightDataType.TYPE_TIME, times);
+		
+		// Flight time is calculated as the last time entry
+		FlightData data = new FlightData(branch);
+		assertEquals(30.2, data.getFlightTime(), 0.000);
+	}
+	
+	/**
+	 * Test method for {@link net.sf.openrocket.simulation.FlightData#getGroundHitVelocity()}.
+	 */
+	@Test
+	public void testGetGroundHitVelocity() {
+		/*
+		 * Setup a flight profile where there is data logged for every second.
+		 * The time events will start at 1, rather than 0 so the time into the
+		 * data log is the index + 1.0 seconds.
+		 * 
+		 * i.e. at second 1, the velocity becomes 1.2 m/s, the altitude of the
+		 * rocket is 1.2, and the LiftOff event is saved.
+		 * 
+		 * This loosely approximates a flight of about 21 seconds where it
+		 * flies up quickly and comes down quickly. The actual flight profile
+		 * is not as important as the fact that a profile exists.
+		 * 
+		 * Each array is stored as 
+		 */
+		final double[] velocities = new double[] {
+				// launch to burn out
+				1.2, 15.0, 31.1, 45.6,
+				// burn out to apogee
+				33.6, 21.2, 14.1, 6.8, 0.0,
+				// apogee to ejection charge
+				2.4, 4.7, 8.6, 9.23,
+				// ejection charge to parachute deployment
+				7.1, 6.2, 6.2, 6.2, 6.2,
+				// parachute deployment to ground hit
+				6.2, 0.0, 0.0
+			};
+		final double[] altitudes = new double[] {
+				// launch to burn out
+				1.2, 16.2, 47.3, 92.9,
+				// burn out to apogee
+				126.5, 147.7, 161.8, 168.6, 168.6,
+				// apogee to ejection charge
+				166.2, 161.5, 152.9, 143.67,
+				// ejection charge to parachute deployment
+				136.57, 113.81, 91.05, 68.29, 45.53,
+				// parachute deployment to ground hit
+				22.77, 0.0, 0.0
+			};
+		final FlightEvent.Type[] eventTypes = new FlightEvent.Type[] {
+				// launch to burn out
+				FlightEvent.Type.LIFTOFF, FlightEvent.Type.LAUNCHROD,
+				FlightEvent.Type.ALTITUDE, FlightEvent.Type.BURNOUT,
+				
+				// burn out to apogee
+				FlightEvent.Type.ALTITUDE, FlightEvent.Type.ALTITUDE,
+				FlightEvent.Type.ALTITUDE, FlightEvent.Type.ALTITUDE,
+				FlightEvent.Type.APOGEE,
+				
+				// apogee to ejection charge
+				FlightEvent.Type.ALTITUDE, FlightEvent.Type.ALTITUDE,
+				FlightEvent.Type.ALTITUDE, FlightEvent.Type.EJECTION_CHARGE,
+				
+				// ejection charge to parachute deployment
+				FlightEvent.Type.ALTITUDE, FlightEvent.Type.RECOVERY_DEVICE_DEPLOYMENT,
+				FlightEvent.Type.ALTITUDE, FlightEvent.Type.ALTITUDE,
+				FlightEvent.Type.ALTITUDE,
+				
+				// parachute deployment to ground hit
+				FlightEvent.Type.GROUND_HIT, FlightEvent.Type.ALTITUDE,
+				FlightEvent.Type.SIMULATION_END
+			};
+		
+		assertEquals(velocities.length, eventTypes.length);
+		assertEquals(velocities.length, altitudes.length);
+		
+		// This flight data branch only needs to record for time,
+		// altitude and velocity.
+		FlightDataBranch branch =
+				new FlightDataBranch("Ground Hit Velocities",
+				                     FlightDataType.TYPE_TIME,
+				                     FlightDataType.TYPE_ALTITUDE,
+				                     FlightDataType.TYPE_VELOCITY_TOTAL);
+		
+		for (int i = 0; i < velocities.length; i++) {
+			branch.addPoint();
+			// the data entries are 1 second ahead of the index
+			double time = i + 1.0;
+			branch.setValue(FlightDataType.TYPE_TIME, time);
+			branch.setValue(FlightDataType.TYPE_ALTITUDE, altitudes[i]);
+			branch.setValue(FlightDataType.TYPE_VELOCITY_TOTAL, velocities[i]);
+			branch.addEvent(new FlightEvent(eventTypes[i], time));
+		}
+		
+		FlightData data = new FlightData(branch);
+		
+		assertEquals(6.2, data.getGroundHitVelocity(), 0.000);
+	}
+	
+}