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Merge pull request #491 from JoePfeiffer/fix-exception

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Clamp pitch and yaw damping moments to avoid numerical instability
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Wes Cravens 2018-12-08 12:30:25 -06:00 committed by GitHub
commit b41af82c90
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1 changed files with 12 additions and 8 deletions
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18
core/src/net/sf/openrocket/aerodynamics/BarrowmanCalculator.java
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@ -718,16 +718,20 @@ public class BarrowmanCalculator extends AbstractAerodynamicCalculator {
// Calculate pitch and yaw damping moments // Calculate pitch and yaw damping moments
double mul = getDampingMultiplier(configuration, conditions, double mul = getDampingMultiplier(configuration, conditions,
conditions.getPitchCenter().x); conditions.getPitchCenter().x);
double pitch = conditions.getPitchRate(); double pitchRate = conditions.getPitchRate();
double yaw = conditions.getYawRate(); double yawRate = conditions.getYawRate();
double vel = conditions.getVelocity(); double velocity = conditions.getVelocity();
vel = MathUtil.max(vel, 1);
mul *= 3; // TODO: Higher damping yields much more realistic apogee turn mul *= 3; // TODO: Higher damping yields much more realistic apogee turn
total.setPitchDampingMoment(mul * MathUtil.sign(pitch) * pow2(pitch / vel)); // find magnitude of damping moments, and clamp so they can't
total.setYawDampingMoment(mul * MathUtil.sign(yaw) * pow2(yaw / vel)); // exceed magnitude of pitch and yaw moments
double pitchDampingMomentMagnitude = MathUtil.min(mul * pow2(pitchRate / velocity), total.getCm());
double yawDampingMomentMagnitude = MathUtil.min(mul * pow2(yawRate / velocity), total.getCyaw());
// multiply by sign of pitch and yaw rates
total.setPitchDampingMoment(MathUtil.sign(pitchRate) * pitchDampingMomentMagnitude);
total.setYawDampingMoment(MathUtil.sign(yawRate) * yawDampingMomentMagnitude);
} }
// TODO: MEDIUM: Are the rotation etc. being added correctly? sin/cos theta? // TODO: MEDIUM: Are the rotation etc. being added correctly? sin/cos theta?