AIDT 온디바이스 STEM 방사광 X선 극저온 고체 핵자기공명(ssNMR) 초고속 매직각 회전(MAS) 100kHz 광학 회전수 및 공압 서보 제어기

using System;
using System.Runtime.CompilerServices;

namespace ZeliDesk.Stem.SolidStateNmr
{
    /// <summary>
    /// 고체 NMR MAS 회전자 타코미터 계측 상태
    /// </summary>
    public readonly ref struct MasTachometerTelemetryState
    {
        public readonly double CurrentMasSpinRateKhz;    // 현재 회전 주파수 [kHz]
        public readonly double TargetMasSpinRateKhz;     // 목표 회전 주파수 [kHz]
        public readonly double BearingGasPressureBar;    // 베어링 가스 압력 [bar]
        public readonly double DriveGasPressureBar;      // 구동 가스 압력 [bar]
        public readonly double CryoGasTemperatureKelvin; // 냉각 가스 온도 [K]
        public readonly double MagicAngleTiltDegrees;    // 현재 매직각 편차 [deg]

        [MethodImpl(MethodImplOptions.AggressiveInlining)]
        public MasTachometerTelemetryState(
            double curRate, double tgtRate, double pBear, double pDrive, double temp, double angle)
        {
            CurrentMasSpinRateKhz = curRate;
            TargetMasSpinRateKhz = tgtRate;
            BearingGasPressureBar = pBear;
            DriveGasPressureBar = pDrive;
            CryoGasTemperatureKelvin = temp;
            MagicAngleTiltDegrees = angle;
        }
    }

    /// <summary>
    /// MAS 압전 비례 밸브 구동 명령
    /// </summary>
    public readonly ref struct MasPneumaticServoCommand
    {
        public readonly double DriveValveDutyCyclePercent;   // 구동 가스 솔레노이드 듀티 [%]
        public readonly double BearingValveDutyCyclePercent; // 베어링 가스 솔레노이드 듀티 [%]
        public readonly double CentrifugalStressMegaPascal;  // 회전자 원심 응력 [MPa]
        public readonly bool SpinRateStable;                // ±2Hz 이내 안정화 여부

        [MethodImpl(MethodImplOptions.AggressiveInlining)]
        public MasPneumaticServoCommand(double driveDuty, double bearDuty, double stress, bool stable)
        {
            DriveValveDutyCyclePercent = driveDuty;
            BearingValveDutyCyclePercent = bearDuty;
            CentrifugalStressMegaPascal = stress;
            SpinRateStable = stable;
        }
    }

    /// <summary>
    /// 10,000Hz 주기 초고속 MAS 100kHz 공압 서보 엔진
    /// </summary>
    public ref struct SolidStateNmrMasPneumaticServoEngine
    {
        private const double IdealMagicAngleDegrees = 54.7356;
        private const double RotorRadiusMm = 0.35;           // 0.7mm 로터 반경 [mm]
        private const double ZirconiaDensityKgM3 = 6000.0;    // ZrO2 밀도 [kg/m^3]

        private double _accumulatedDriveDuty;
        private double _prevErrorKhz;

        [MethodImpl(MethodImplOptions.AggressiveInlining)]
        public MasPneumaticServoCommand UpdateServo(in MasTachometerTelemetryState state, double dtSeconds)
        {
            double errorKhz = state.TargetMasSpinRateKhz - state.CurrentMasSpinRateKhz;
            double errorDerivative = (dtSeconds > 1e-9) ? (errorKhz - _prevErrorKhz) / dtSeconds : 0.0;
            _prevErrorKhz = errorKhz;

            // PI 적분 누적 (구동 밸브 듀티 제어)
            _accumulatedDriveDuty += 0.85 * errorKhz * dtSeconds;
            _accumulatedDriveDuty = Math.Clamp(_accumulatedDriveDuty, 5.0, 95.0);

            double targetDriveDuty = _accumulatedDriveDuty + 1.45 * errorKhz + 0.025 * errorDerivative;
            targetDriveDuty = Math.Clamp(targetDriveDuty, 0.0, 100.0);

            // 베어링 가스 압력 보상: 고속 회전 시 베르누이 부양력을 위해 회전수 제곱에 비례 증압
            double requiredBearingPressureBar = 1.5 + 2.5 * Math.Pow(state.CurrentMasSpinRateKhz / 100.0, 2.0);
            double bearingError = requiredBearingPressureBar - state.BearingGasPressureBar;
            double targetBearingDuty = Math.Clamp(40.0 + 15.0 * bearingError, 10.0, 95.0);

            // 원심 응력 계산 sigma = rho * omega^2 * r^2
            double omegaRadS = 2.0 * Math.PI * (state.CurrentMasSpinRateKhz * 1000.0);
            double rMeters = RotorRadiusMm * 1e-3;
            double stressPascal = ZirconiaDensityKgM3 * Math.Pow(omegaRadS * rMeters, 2.0);
            double stressMpa = stressPascal / 1e6;

            // 회전 안정도 판정: 오차 0.002 kHz (2Hz) 이내 & 매직각 정렬 0.01도 이내
            bool angleAligned = Math.Abs(state.MagicAngleTiltDegrees - IdealMagicAngleDegrees) < 0.01;
            bool stable = (Math.Abs(errorKhz) < 0.002) && angleAligned;

            return new MasPneumaticServoCommand(targetDriveDuty, targetBearingDuty, stressMpa, stable);
        }
    }
}