--- /dev/null
+package net.sf.openrocket.motor;
+
+import java.text.Collator;
+import java.util.Comparator;
+import java.util.Locale;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
+import net.sf.openrocket.util.Coordinate;
+import net.sf.openrocket.util.MathUtil;
+
+
+
+/**
+ * Abstract base class for motors. The methods that must be implemented are
+ * {@link #getTotalTime()}, {@link #getThrust(double)} and {@link #getCG(double)}.
+ * Additionally the method {@link #getMaxThrust()} may be overridden for efficiency.
+ * <p>
+ *
+ * NOTE: The current implementation of {@link #getAverageTime()} and
+ * {@link #getAverageThrust()} assume that the class is immutable!
+ *
+ * @author Sampo Niskanen <sampo.niskanen@iki.fi>
+ */
+public abstract class Motor implements Comparable<Motor> {
+
+ /**
+ * Enum of rocket motor types.
+ *
+ * @author Sampo Niskanen <sampo.niskanen@iki.fi>
+ */
+ public enum Type {
+ SINGLE("Single-use", "Single-use solid propellant motor"),
+ RELOAD("Reloadable", "Reloadable solid propellant motor"),
+ HYBRID("Hybrid", "Hybrid rocket motor engine"),
+ UNKNOWN("Unknown", "Unknown motor type");
+
+ private final String name;
+ private final String description;
+
+ Type(String name, String description) {
+ this.name = name;
+ this.description = description;
+ }
+
+ /**
+ * Return a short name of this motor type.
+ * @return a short name of the motor type.
+ */
+ public String getName() {
+ return name;
+ }
+
+ /**
+ * Return a long description of this motor type.
+ * @return a description of the motor type.
+ */
+ public String getDescription() {
+ return description;
+ }
+
+ @Override
+ public String toString() {
+ return name;
+ }
+ }
+
+
+ /**
+ * Ejection charge delay value signifying a "plugged" motor with no ejection charge.
+ * The value is that of <code>Double.POSITIVE_INFINITY</code>.
+ */
+ public static final double PLUGGED = Double.POSITIVE_INFINITY;
+
+
+ /**
+ * Below what portion of maximum thrust is the motor chosen to be off when
+ * calculating average thrust and burn time. NFPA 1125 defines the "official"
+ * burn time to be the time which the motor produces over 5% of its maximum thrust.
+ */
+ public static final double AVERAGE_MARGINAL = 0.05;
+
+ /* All data is cached, so divisions can be very tight. */
+ private static final int DIVISIONS = 1000;
+
+
+ // Comparators:
+ private static final Collator COLLATOR = Collator.getInstance(Locale.US);
+ static {
+ COLLATOR.setStrength(Collator.PRIMARY);
+ }
+ private static DesignationComparator DESIGNATION_COMPARATOR = new DesignationComparator();
+
+
+
+
+ private final Manufacturer manufacturer;
+ private final String designation;
+ private final String description;
+ private final Type motorType;
+
+ private final double[] delays;
+
+ private final double diameter;
+ private final double length;
+
+ /* Cached data */
+ private double maxThrust = -1;
+ private double avgTime = -1;
+ private double avgThrust = -1;
+ private double totalImpulse = -1;
+
+
+
+ /**
+ * Sole constructor. None of the parameters may be <code>null</code>.
+ *
+ * @param manufacturer the manufacturer of the motor.
+ * @param designation the motor designation.
+ * @param description further description, including any comments on the origin
+ * of the thrust curve.
+ * @param delays an array of the standard ejection charge delays. A plugged
+ * motor (no ejection charge) is specified by a delay of
+ * {@link #PLUGGED} (<code>Double.POSITIVE_INFINITY</code>).
+ * @param diameter maximum diameter of the motor
+ * @param length length of the motor
+ */
+ protected Motor(Manufacturer manufacturer, String designation, String description,
+ Type type, double[] delays, double diameter, double length) {
+
+ if (manufacturer == null || designation == null || description == null ||
+ type == null || delays == null) {
+ throw new IllegalArgumentException("Parameters cannot be null.");
+ }
+
+ this.manufacturer = manufacturer;
+ this.designation = designation;
+ this.description = description.trim();
+ this.motorType = type;
+ this.delays = delays.clone();
+ this.diameter = diameter;
+ this.length = length;
+ }
+
+
+
+ /**
+ * Return the total burn time of the motor. The method {@link #getThrust(double)}
+ * must return zero for time values greater than the return value.
+ *
+ * @return the total burn time of the motor.
+ */
+ public abstract double getTotalTime();
+
+
+ /**
+ * Return the thrust of the motor at the specified time.
+ *
+ * @param time time since the ignition of the motor.
+ * @return the thrust at the specified time.
+ */
+ public abstract double getThrust(double time);
+
+
+ /**
+ * Return the average thrust of the motor between times t1 and t2.
+ *
+ * @param t1 starting time since the ignition of the motor.
+ * @param t2 end time since the ignition of the motor.
+ * @return the average thrust during the time period.
+ */
+ /* TODO: MEDIUM: Implement better method in subclass */
+ public double getThrust(double t1, double t2) {
+ double f = 0;
+ f += getThrust(t1);
+ f += getThrust(0.8*t1 + 0.2*t2);
+ f += getThrust(0.6*t1 + 0.4*t2);
+ f += getThrust(0.4*t1 + 0.6*t2);
+ f += getThrust(0.2*t1 + 0.8*t2);
+ f += getThrust(t2);
+ return f/6;
+ }
+
+
+ /**
+ * Return the mass and CG of the motor at the specified time.
+ *
+ * @param time time since the ignition of the motor.
+ * @return the mass and CG of the motor.
+ */
+ public abstract Coordinate getCG(double time);
+
+
+
+ /**
+ * Return the mass of the motor at the specified time. The original mass
+ * of the motor can be queried by <code>getMass(0)</code> and the burnt mass
+ * by <code>getMass(Double.MAX_VALUE)</code>.
+ *
+ * @param time time since the ignition of the motor.
+ * @return the mass of the motor.
+ */
+ public double getMass(double time) {
+ return getCG(time).weight;
+ }
+
+
+ /**
+ * Return the longitudal moment of inertia of the motor at the specified time.
+ * This default method assumes that the mass of the motor is evenly distributed
+ * in a cylinder with the diameter and length of the motor.
+ *
+ * @param time time since the ignition of the motor.
+ * @return the longitudal moment of inertia of the motor.
+ */
+ public double getLongitudalInertia(double time) {
+ return getMass(time) * (3.0*MathUtil.pow2(diameter/2) + MathUtil.pow2(length))/12;
+ }
+
+
+
+ /**
+ * Return the rotational moment of inertia of the motor at the specified time.
+ * This default method assumes that the mass of the motor is evenly distributed
+ * in a cylinder with the diameter and length of the motor.
+ *
+ * @param time time since the ignition of the motor.
+ * @return the rotational moment of inertia of the motor.
+ */
+ public double getRotationalInertia(double time) {
+ return getMass(time) * MathUtil.pow2(diameter) / 8;
+ }
+
+
+
+
+ /**
+ * Return the maximum thrust. This implementation slices through the thrust curve
+ * searching for the maximum thrust. Subclasses may wish to override this with a
+ * more efficient method.
+ *
+ * @return the maximum thrust of the motor
+ */
+ public double getMaxThrust() {
+ if (maxThrust < 0) {
+ double time = getTotalTime();
+ maxThrust = 0;
+
+ for (int i=0; i < DIVISIONS; i++) {
+ double t = time * i / DIVISIONS;
+ double thrust = getThrust(t);
+
+ if (thrust > maxThrust)
+ maxThrust = thrust;
+ }
+ }
+ return maxThrust;
+ }
+
+
+ /**
+ * Return the time used in calculating the average thrust. The time is the
+ * length of time that the motor produces over 5% ({@link #AVERAGE_MARGINAL})
+ * of its maximum thrust.
+ *
+ * @return the nominal burn time.
+ */
+ public double getAverageTime() {
+ // Compute average time lazily
+ if (avgTime < 0) {
+ double max = getMaxThrust();
+ double time = getTotalTime();
+
+ avgTime = 0;
+ for (int i=0; i <= DIVISIONS; i++) {
+ double t = i*time/DIVISIONS;
+ if (getThrust(t) >= max*AVERAGE_MARGINAL)
+ avgTime++;
+ }
+ avgTime *= time/(DIVISIONS+1);
+
+ if (Double.isNaN(avgTime))
+ throw new RuntimeException("Calculated avg. time is NaN for motor "+this);
+
+ }
+ return avgTime;
+ }
+
+
+ /**
+ * Return the calculated average thrust during the time the motor produces
+ * over 5% ({@link #AVERAGE_MARGINAL}) of its thrust.
+ *
+ * @return the nominal average thrust.
+ */
+ public double getAverageThrust() {
+ // Compute average thrust lazily
+ if (avgThrust < 0) {
+ double max = getMaxThrust();
+ double time = getTotalTime();
+ int points = 0;
+
+ avgThrust = 0;
+ for (int i=0; i <= DIVISIONS; i++) {
+ double t = i*time/DIVISIONS;
+ double thrust = getThrust(t);
+ if (thrust >= max*AVERAGE_MARGINAL) {
+ avgThrust += thrust;
+ points++;
+ }
+ }
+ if (points > 0)
+ avgThrust /= points;
+
+ if (Double.isNaN(avgThrust))
+ throw new RuntimeException("Calculated average thrust is NaN for motor "+this);
+ }
+ return avgThrust;
+ }
+
+
+ /**
+ * Return the total impulse of the motor. This is calculated from the entire
+ * burn time, and therefore may differ from the value of {@link #getAverageTime()}
+ * and {@link #getAverageThrust()} multiplied together.
+ *
+ * @return the total impulse of the motor.
+ */
+ public double getTotalImpulse() {
+ // Compute total impulse lazily
+ if (totalImpulse < 0) {
+ double time = getTotalTime();
+ double f0, t0;
+
+ totalImpulse = 0;
+ t0 = 0;
+ f0 = getThrust(0);
+ for (int i=1; i < DIVISIONS; i++) {
+ double t1 = time * i / DIVISIONS;
+ double f1 = getThrust(t1);
+ totalImpulse += 0.5*(f0+f1)*(t1-t0);
+ t0 = t1;
+ f0 = f1;
+ }
+
+ if (Double.isNaN(totalImpulse))
+ throw new RuntimeException("Calculated total impulse is NaN for motor "+this);
+ }
+ return totalImpulse;
+ }
+
+
+ /**
+ * Return the manufacturer of the motor.
+ *
+ * @return the manufacturer
+ */
+ public Manufacturer getManufacturer() {
+ return manufacturer;
+ }
+
+ /**
+ * Return the designation of the motor.
+ *
+ * @return the designation
+ */
+ public String getDesignation() {
+ return designation;
+ }
+
+ /**
+ * Return the designation of the motor, including a delay.
+ *
+ * @param delay the delay of the motor.
+ * @return designation with delay.
+ */
+ public String getDesignation(double delay) {
+ return getDesignation() + "-" + getDelayString(delay);
+ }
+
+
+ /**
+ * Return extra description for the motor. This may include for example
+ * comments on the source of the thrust curve. The returned <code>String</code>
+ * may include new-lines.
+ *
+ * @return the description
+ */
+ public String getDescription() {
+ return description;
+ }
+
+
+ /**
+ * Return the motor type.
+ *
+ * @return the motorType
+ */
+ public Type getMotorType() {
+ return motorType;
+ }
+
+
+
+ /**
+ * Return the standard ejection charge delays for the motor. "Plugged" motors
+ * with no ejection charge are signified by the value {@link #PLUGGED}
+ * (<code>Double.POSITIVE_INFINITY</code>).
+ *
+ * @return the list of standard ejection charge delays, which may be empty.
+ */
+ public double[] getStandardDelays() {
+ return delays.clone();
+ }
+
+ /**
+ * Return the maximum diameter of the motor.
+ *
+ * @return the diameter
+ */
+ public double getDiameter() {
+ return diameter;
+ }
+
+ /**
+ * Return the length of the motor. This should be a "characteristic" length,
+ * and the exact definition may depend on the motor type. Typically this should
+ * be the length from the bottom of the motor to the end of the maximum diameter
+ * portion, ignoring any smaller ejection charge compartments.
+ *
+ * @return the length
+ */
+ public double getLength() {
+ return length;
+ }
+
+
+ /**
+ * Compares two <code>Motor</code> objects. The motors are considered equal
+ * if they have identical manufacturers, designations and types, near-identical
+ * dimensions, burn times and delays and near-identical thrust curves
+ * (sampled at 10 equidistant points).
+ * <p>
+ * The comment field is ignored when comparing equality.
+ */
+ @Override
+ public boolean equals(Object o) {
+ if (!(o instanceof Motor))
+ return false;
+
+ Motor other = (Motor) o;
+
+ // Tests manufacturer, designation, diameter and length
+ if (this.compareTo(other) != 0)
+ return false;
+
+ if (Math.abs(this.getTotalTime() - other.getTotalTime()) > 0.5 ||
+ this.motorType != other.motorType ||
+ this.delays.length != other.delays.length) {
+
+ return false;
+ }
+
+ for (int i=0; i < delays.length; i++) {
+ // INF - INF == NaN, which produces false when compared
+ if (Math.abs(this.delays[i] - other.delays[i]) > 0.5) {
+ return false;
+ }
+ }
+
+ double time = getTotalTime();
+ for (int i=0; i < 10; i++) {
+ double t = time * i/10;
+ if (Math.abs(this.getThrust(t) - other.getThrust(t)) > 1) {
+ return false;
+ }
+ }
+ return true;
+ }
+
+ /**
+ * A <code>hashCode</code> method compatible with the <code>equals</code>
+ * method.
+ */
+ @Override
+ public int hashCode() {
+ return (manufacturer.hashCode() + designation.hashCode() +
+ ((int)(length*1000)) + ((int)(diameter*1000)));
+ }
+
+
+
+ @Override
+ public String toString() {
+ return manufacturer + " " + designation;
+ }
+
+
+ ////////// Static methods
+
+
+ /**
+ * Return a String representation of a delay time. If the delay is {@link #PLUGGED},
+ * returns "P".
+ *
+ * @param delay the delay time.
+ * @return the <code>String</code> representation.
+ */
+ public static String getDelayString(double delay) {
+ return getDelayString(delay,"P");
+ }
+
+ /**
+ * Return a String representation of a delay time. If the delay is {@link #PLUGGED},
+ * <code>plugged</code> is returned.
+ *
+ * @param delay the delay time.
+ * @param plugged the return value if there is no ejection charge.
+ * @return the String representation.
+ */
+ public static String getDelayString(double delay, String plugged) {
+ if (delay == PLUGGED)
+ return plugged;
+ delay = Math.rint(delay*10)/10;
+ if (MathUtil.equals(delay, Math.rint(delay)))
+ return "" + ((int)delay);
+ return "" + delay;
+ }
+
+
+
+
+ //////////// Comparation
+
+
+
+ @Override
+ public int compareTo(Motor other) {
+ int value;
+
+ // 1. Manufacturer
+ value = COLLATOR.compare(this.manufacturer.getDisplayName(),
+ other.manufacturer.getDisplayName());
+ if (value != 0)
+ return value;
+
+ // 2. Designation
+ value = DESIGNATION_COMPARATOR.compare(this.designation, other.designation);
+ if (value != 0)
+ return value;
+
+ // 3. Diameter
+ value = (int)((this.diameter - other.diameter)*1000000);
+ if (value != 0)
+ return value;
+
+ // 4. Length
+ value = (int)((this.length - other.length)*1000000);
+ if (value != 0)
+ return value;
+
+ // 5. Total impulse
+ value = (int)((this.getTotalImpulse() - other.getTotalImpulse())*1000);
+ return value;
+ }
+
+
+
+ public static Comparator<String> getDesignationComparator() {
+ return DESIGNATION_COMPARATOR;
+ }
+
+
+ /**
+ * Compares two motors by their designations. The motors are ordered first
+ * by their motor class, second by their average thrust and lastly by any
+ * extra modifiers at the end of the designation.
+ *
+ * @author Sampo Niskanen <sampo.niskanen@iki.fi>
+ */
+ private static class DesignationComparator implements Comparator<String> {
+ private Pattern pattern =
+ Pattern.compile("^([0-9][0-9]+|1/([1-8]))?([a-zA-Z])([0-9]+)(.*?)$");
+
+ @Override
+ public int compare(String o1, String o2) {
+ int value;
+ Matcher m1, m2;
+
+ m1 = pattern.matcher(o1);
+ m2 = pattern.matcher(o2);
+
+ if (m1.find() && m2.find()) {
+
+ String o1Class = m1.group(3);
+ int o1Thrust = Integer.parseInt(m1.group(4));
+ String o1Extra = m1.group(5);
+
+ String o2Class = m2.group(3);
+ int o2Thrust = Integer.parseInt(m2.group(4));
+ String o2Extra = m2.group(5);
+
+ // 1. Motor class
+ if (o1Class.equalsIgnoreCase("A") && o2Class.equalsIgnoreCase("A")) {
+ // 1/2A and 1/4A comparison
+ String sub1 = m1.group(2);
+ String sub2 = m2.group(2);
+
+ if (sub1 != null || sub2 != null) {
+ if (sub1 == null)
+ sub1 = "1";
+ if (sub2 == null)
+ sub2 = "1";
+ value = -COLLATOR.compare(sub1,sub2);
+ if (value != 0)
+ return value;
+ }
+ }
+ value = COLLATOR.compare(o1Class,o2Class);
+ if (value != 0)
+ return value;
+
+ // 2. Average thrust
+ if (o1Thrust != o2Thrust)
+ return o1Thrust - o2Thrust;
+
+ // 3. Extra modifier
+ return COLLATOR.compare(o1Extra, o2Extra);
+
+ } else {
+
+ System.out.println("Falling back");
+ System.out.println("o1:"+o1 + " o2:"+o2);
+
+ // Not understandable designation, simply compare strings
+ return COLLATOR.compare(o1, o2);
+ }
+ }
+ }
+}
projects / debian / openrocket / blobdiff