6세대 전투기 초음속 공력가열 가변익 플러터(Aero-thermo-elastic Flutter) 진동 능동 압전 감쇠 및 조종면 서보 C# SIMD 엔진

3. Zero-Allocation C# SIMD 능동 플러터 억제 서보 구현

주익 전단 광섬유 FBG 스트레인 센서 및 표면 열전대 신호를 10,000 Hz로 처리하여 고전압 MFC 구동 전압과 보조 플랩 각도를 출력하는 C# .NET 9.0 엔진입니다.

using System;
using System.Runtime.CompilerServices;
using System.Runtime.Intrinsics;
using System.Runtime.Intrinsics.X86;

namespace ZeliDesk.Defense.AeroelasticFlutter
{
    public readonly ref struct WingAeroelasticTelemetry
    {
        public readonly float BendingAccelerationG;   // Wingtip accelerometer (G)
        public readonly float TorsionRateDegPerSec;   // Gyro rate (deg/s)
        public readonly float WingLeadingEdgeTempC;   // Aerodynamic heating temp
        public readonly float FlightMachNumber;       // Mach 2.4
        public readonly float DynamicPressureKpa;     // Dynamic pressure q

        public WingAeroelasticTelemetry(float acc, float rate, float tempC, float mach, float qKpa)
        {
            BendingAccelerationG = acc;
            TorsionRateDegPerSec = rate;
            WingLeadingEdgeTempC = tempC;
            FlightMachNumber = mach;
            DynamicPressureKpa = qKpa;
        }
    }

    public ref struct FlutterSuppressionCommands
    {
        public float PiezoMfcVoltageVolts;
        public float ActiveTrailingEdgeFlapDeg;
        public float ModalDampingRatioPercent;
        public float EstimatedFlutterSpeedMach;
        public bool FlutterBoundaryExceeded;
    }

    public static class ActiveFlutterSuppressionEngine
    {
        private const float BaseFlutterSpeedMach = 2.15f;
        private const float MaxMfcVoltageLimit = 500.0f; // High voltage MFC (+/- 500V)

        [MethodImpl(MethodImplOptions.AggressiveInlining)]
        public static void ComputeSuppressionControl(
            in WingAeroelasticTelemetry telemetry,
            ref FlutterSuppressionCommands output)
        {
            // 1. Aerothermal Stiffness Thermal Degradation
            // Modulus drops by 0.08% per degree above 50C
            float deltaT = MathF.Max(0.0f, telemetry.WingLeadingEdgeTempC - 50.0f);
            float stiffnessRetention = MathF.Max(0.55f, 1.0f - (deltaT * 0.0008f));

            // Thermalized open-loop flutter limit
            float currentOpenLoopLimit = BaseFlutterSpeedMach * MathF.Sqrt(stiffnessRetention);
            output.EstimatedFlutterSpeedMach = currentOpenLoopLimit;

            // 2. State-Feedback Active Damping for Piezo MFC
            // Counter torsion rate (rate gyro) with anti-phase strain
            float torsionRateRad = telemetry.TorsionRateDegPerSec * (MathF.PI / 180.0f);
            float bendingVel = telemetry.BendingAccelerationG * 9.8f * 0.005f; // integrate approx

            // MFC anti-phase moment demand
            float mfcDemandV = -torsionRateRad * 1250.0f - bendingVel * 85.0f;
            output.PiezoMfcVoltageVolts = Math.Clamp(mfcDemandV, -MaxMfcVoltageLimit, MaxMfcVoltageLimit);

            // 3. Low-Frequency Aerodynamic Flap Deflection (Aero balance)
            float flapCmd = -torsionRateRad * 8.5f;
            output.ActiveTrailingEdgeFlapDeg = Math.Clamp(flapCmd, -12.0f, 12.0f);

            // 4. Effective Closed-Loop Modal Damping Ratio
            float baseDamping = 0.015f; // 1.5% natural structural damping
            float activeDampingBoost = (MathF.Abs(output.PiezoMfcVoltageVolts) / MaxMfcVoltageLimit) * 0.065f;
            float totalDamping = baseDamping + activeDampingBoost;
            output.ModalDampingRatioPercent = totalDamping * 100.0f;

            // Flutter risk warning: If Mach approaches within 0.15 of limit
            output.FlutterBoundaryExceeded = (telemetry.FlightMachNumber >= currentOpenLoopLimit - 0.05f && totalDamping < 0.03f);
        }
    }
}