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Add adjustment os adhesion substeps due to decreasing screen fps
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@peternewell
peternewell committed Oct 25, 2023
1 parent 1fdec87 commit 2df2ab4
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Showing 4 changed files with 39 additions and 73 deletions.
2 changes: 2 additions & 0 deletions Source/Orts.Simulation/Simulation/Physics/Train.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -195,6 +195,8 @@ public int ActivityDurationS

public bool HasControlCarWithGear = false;

public float ScreenFrameRate;

//To investigate coupler breaks on route
private bool numOfCouplerBreaksNoted = false;
public static int NumOfCouplerBreaks = 0;//Debrief Eval
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4 changes: 3 additions & 1 deletion Source/Orts.Simulation/Simulation/RollingStocks/MSTSLocomotive.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -149,6 +149,7 @@ public enum SoundState

float ZeroSpeedAdhesionBase;


public float FilteredBrakePipeFlowM3pS;
public IIRFilter AFMFilter;

Expand Down Expand Up @@ -2799,13 +2800,14 @@ public virtual void AdvancedAdhesion(float elapsedClockSeconds)

foreach (var axle in LocomotiveAxles)
{
axle.BrakeRetardForceN = BrakeRetardForceN/LocomotiveAxles.Count;
axle.BrakeRetardForceN = BrakeRetardForceN / LocomotiveAxles.Count;
axle.TrainSpeedMpS = SpeedMpS; //Set the train speed of the axle mod
axle.WheelRadiusM = DriverWheelRadiusM;
axle.WheelDistanceGaugeM = TrackGaugeM;
axle.CurrentCurveRadiusM = CurrentCurveRadiusM;
axle.BogieRigidWheelBaseM = RigidWheelBaseM;
axle.CurtiusKnifflerZeroSpeed = ZeroSpeedAdhesionBase;
axle.ScreenFrameRate = Train.ScreenFrameRate;
}

LocomotiveAxles.Update(elapsedClockSeconds);
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102 changes: 30 additions & 72 deletions Source/Orts.Simulation/Simulation/RollingStocks/SubSystems/PowerTransmissions/Axle.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -516,6 +516,11 @@ public float TransmissionEfficiency
/// </summary>
public float CurtiusKnifflerZeroSpeed;

/// <summary>
/// Simulator FPS
/// </summary>
public float ScreenFrameRate;

/// <summary>
/// Wheel adhesion as calculated by Polach
/// </summary>
Expand Down Expand Up @@ -643,15 +648,6 @@ public void ComputeWheelSlipThresholdMpS()
}
}
WheelSlipThresholdMpS = (float)Math.Max((a + b) / 2, MpS.FromKpH(0.1f));

if (IsWheelSlip)
{
// Trace.TraceInformation("Fx Values - a {0} fa1 {1} b {2} fb1 {3} s {4} fs {5} t {6} ft {7} u {8} fu {9} v {10} fv {11} x {12} fx {13} y {14} fy {15} Speed {16} Threshold {17} Fslip {18} SlipSpeed {19}", a, fa1, b, fb1, s, fs, t, ft, u, fu, v, fv, x, fx, y, fy, TrainSpeedMpS, WheelSlipThresholdMpS, fslip, SlipSpeedMpS);

// Trace.TraceInformation("Threshold Speed - {0}", WheelSlipThresholdMpS);

}

}

/// <summary>
Expand Down Expand Up @@ -878,53 +874,47 @@ void Integrate(float elapsedClockSeconds)
{
if (elapsedClockSeconds <= 0) return;
double prevSpeedMpS = AxleSpeedMpS;
/*
if (Math.Abs(integratorError) > Math.Max((Math.Abs(SlipSpeedMpS) - 1) * 0.01, 0.001))
{
++NumOfSubstepsPS;
waitBeforeSpeedingUp = 100;

var upperSubStepStartingLimit = 120;
var upperSubStepLimit = upperSubStepStartingLimit;
var lowerSubStepLimit = 1;

// Trace.TraceInformation("Algorithim Increase - Steps {0} Err {1}", NumOfSubstepsPS, integratorError);
var screenFrameUpperLimit = 60;
var screenFrameLowerLimit = 40;

// Reduces the number of substeps if screen FPS drops
if (ScreenFrameRate >= screenFrameUpperLimit)
{
upperSubStepLimit = upperSubStepStartingLimit;
}
else if (ScreenFrameRate < screenFrameLowerLimit)
{
upperSubStepLimit = upperSubStepStartingLimit * (screenFrameLowerLimit / screenFrameUpperLimit);
}
else
{
if (--waitBeforeSpeedingUp <= 0) //wait for a while before speeding up the integration
{
--NumOfSubstepsPS;
waitBeforeSpeedingUp = 10; //not so fast ;)
// Trace.TraceInformation("Algorithim Decrease - Steps {0} Err {1}", NumOfSubstepsPS, integratorError);
}
upperSubStepLimit = (int) ((ScreenFrameRate / 60) * upperSubStepStartingLimit);
}

NumOfSubstepsPS = Math.Max(Math.Min(NumOfSubstepsPS, 130), 1);
*/
// use straight line graph approximation
// Points are 1 = (0, upperLimit) and 2 = (threshold, lowerLimit)

var upperLimit = 130;
var lowerLimit = 1;
var AdhesGrad = ((upperLimit - lowerLimit) / (WheelSlipThresholdMpS - 0));
var targetNumOfSubstepsPS = Math.Abs((AdhesGrad * SlipSpeedMpS) + lowerLimit);
// use straight line graph approximation to increase substeps as slipspeed increases towards the threshold speed point
// Points are 1 = (0, upperLimit) and 2 = (threshold, lowerLimit)
var AdhesGrad = ((upperSubStepLimit - lowerSubStepLimit) / (WheelSlipThresholdMpS - 0));
var targetNumOfSubstepsPS = Math.Abs((AdhesGrad * SlipSpeedMpS) + lowerSubStepLimit);
if (float.IsNaN((float)targetNumOfSubstepsPS)) targetNumOfSubstepsPS = 1;

if (SlipSpeedMpS > WheelSlipThresholdMpS) // if in wheel slip then maximise the substeps
{
targetNumOfSubstepsPS = 130;
targetNumOfSubstepsPS = upperSubStepLimit;
}

// Trace.TraceInformation("Grad - {0} AdhesGrad {1} SlipSpeedMps {2} Threshold {3}", temp, AdhesGrad, SlipSpeedMpS, WheelSlipThresholdMpS);

if (Math.Abs(integratorError) < 0.000277 && !IsWheelSlip && !IsWheelSlipWarning && SlipSpeedMpS < 0.4 * WheelSlipThresholdMpS)
{
if (--waitBeforeIntegreationRate <= 0) //wait for a while before changing the integration rate
{
NumOfSubstepsPS -= 2;
NumOfSubstepsPS -= 2; // decrease substeps when under low slip conditions
waitBeforeIntegreationRate = 20;
}
}
// else if (targetNumOfSubstepsPS > NumOfSubstepsPS && Math.Abs(integratorError) > Math.Max((Math.Abs(SlipSpeedMpS) - 1) * 0.01, 0.001)) // increase substeps
else if (targetNumOfSubstepsPS > NumOfSubstepsPS) // increase substeps
{
if (--waitBeforeIntegreationRate <= 0 ) //wait for a while before changing the integration rate
Expand All @@ -942,13 +932,11 @@ void Integrate(float elapsedClockSeconds)
}
}

if (NumOfSubstepsPS < lowerLimit)
NumOfSubstepsPS = lowerLimit;
if (NumOfSubstepsPS < lowerSubStepLimit)
NumOfSubstepsPS = lowerSubStepLimit;

if (NumOfSubstepsPS > upperLimit)
NumOfSubstepsPS = upperLimit;

// Trace.TraceInformation("Grad - {0} AdhesGrad {1} SlipSpeedMps {2} Threshold {3} NumStepsPS {4} Error {5}", targetNumOfSubstepsPS, AdhesGrad, SlipSpeedMpS, WheelSlipThresholdMpS, NumOfSubstepsPS, integratorError);
if (NumOfSubstepsPS > upperSubStepLimit)
NumOfSubstepsPS = upperSubStepLimit;

double dt = elapsedClockSeconds / NumOfSubstepsPS;
double hdt = dt / 2;
Expand All @@ -957,18 +945,6 @@ void Integrate(float elapsedClockSeconds)
for (int i = 0; i < NumOfSubstepsPS; i++)
{
var k1 = GetAxleMotionVariation(AxleSpeedMpS, dt);
/*
if (i == 0)
{
if (k1.Item1 * dt > Math.Max((Math.Abs(SlipSpeedMpS) - 1) * 10, 1) / 100)
{
// NumOfSubstepsPS = Math.Min(NumOfSubstepsPS + 5, 130);
// Trace.TraceInformation("Algorithim Change - k1 - Number of Steps {0}", NumOfSubstepsPS);
dt = elapsedClockSeconds / NumOfSubstepsPS;
hdt = dt / 2;
}
}
*/
var k2 = GetAxleMotionVariation(AxleSpeedMpS + k1.Item1 * hdt, hdt);
var k3 = GetAxleMotionVariation(AxleSpeedMpS + k2.Item1 * hdt, hdt);
var k4 = GetAxleMotionVariation(AxleSpeedMpS + k3.Item1 * dt, dt);
Expand Down Expand Up @@ -998,8 +974,6 @@ public virtual void Update(float timeSpan)
axleStaticForceN = AxleWeightN * SlipCharacteristics(0);
ComputeWheelSlipThresholdMpS();

// Trace.TraceInformation("Threshold - Threshold {0} SlipSpeed {1} Speed {2}", WheelSlipThresholdMpS, SlipSpeedMpS, TrainSpeedMpS);

if (count < 6 && count++ == 5)
{
TrainSpeedMpS = 10 / 3.6f;
Expand Down Expand Up @@ -1050,7 +1024,6 @@ public virtual void Update(float timeSpan)
if (WheelSlipTimeS > 1)
{
IsWheelSlip = IsWheelSlipWarning = true;
// Trace.TraceInformation("Wheel Slip Triggered");
}
WheelSlipTimeS += timeSpan;
}
Expand Down Expand Up @@ -1153,13 +1126,9 @@ public void Update()
if (float.IsNaN((float)Sy)) Sy = 0;//avoid NaN when first starting OR
Sy2 = Sy * Sy;

// Trace.TraceInformation("Spin - {0} FlangeAngle {1} wheelRadius {2} Speed {3}", spinM1, Axle.WheelFlangeAngleRad, wheelRadiusMM, trainSpeedMpS);

Syc = Sy + (spinM1 * a_HertzianM);
Syc2 = Syc * Syc;

// Trace.TraceInformation("Sy - {0} Syc {1} Spin {2} a_hertz {3}", Sy, Syc, spinM1, a_HertzianMM);

// calculate "standard" Polach adhesion parameters as straight line approximations as u varies - these values are capped at the moment at the u=0.3 level
// Taking them lower may reduce the stability of the calculations
polach_A = 0.4;
Expand All @@ -1176,8 +1145,6 @@ public double SlipCharacteristics(double slipSpeedMpS)
{
var polach_uadhesion = zeroSpeedAdhesion * (((1 - polach_A) * Math.Exp(-polach_B * slipSpeedMpS)) + polach_A);

// Trace.TraceInformation("Polach Adhesion - {0} ZeroAdhesion {1} RawPolach {2} SlipSpeed {3}", polach_uadhesion, zeroSpeedAdhesion, (((1 - polach_A) * Math.Exp(-polach_B * slipSpeedMpS)) + polach_A), slipSpeedMpS);

if (trainSpeedMpS < 0.05f)
return polach_uadhesion;

Expand Down Expand Up @@ -1205,15 +1172,6 @@ public double SlipCharacteristics(double slipSpeedMpS)

var fx = (f * Sx / Sc) / wheelLoadN;


// if (slipSpeedMpS == 0.025f || slipSpeedMpS == 0.05f || slipSpeedMpS == 0.1f || slipSpeedMpS == 0.15f || slipSpeedMpS == 0.2f)
if (Axle.IsWheelSlip)
{
// Trace.TraceInformation("Negative Fx - Fx {0} Speed {1} SlipSpeed {2} Sx {3} PolachAdhesion {4} adhesionComponent {5} slipComponent {6} Polach_Ks {7} Stiffness2 {8} SlipForce {9} Sc {10} WheelLoad {11} Syc {12} Hertz_a {13} Sy {14} Threshold {15} DriveForce {16} Steps {17} IsWheelSlip {18} IsWheelSlipWarning {19}", fx, (float)trainSpeedMpS, (float)slipSpeedMpS, (float)Sx, polach_uadhesion, adhesionComponent, slipComponent, polach_Ks, Stiffness2, f, Sc, wheelLoadN, Syc, a_HertzianMM, Sy, Axle.WheelSlipThresholdMpS, Axle.DriveForceN, Axle.NumOfSubstepsPS, Axle.IsWheelSlip, Axle.IsWheelSlipWarning);

}


return fx;
}
}
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4 changes: 4 additions & 0 deletions Source/RunActivity/Viewer3D/Popups/HUDWindow.cs
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Expand Up @@ -474,6 +474,10 @@ void TextPageCommon(TableData table)
TableAddLabelValue(table, Viewer.Catalog.GetString("FPS"), "{0:F0}", Viewer.RenderProcess.FrameRate.SmoothedValue);
TableAddLine(table);

// Used in axle module to adjust substeps for frame rate drops
var mstsLocomotive = Viewer.PlayerLocomotive as MSTSLocomotive;
Viewer.PlayerTrain.ScreenFrameRate = Viewer.RenderProcess.FrameRate.SmoothedValue;

if (Viewer.PlayerLocomotive.Train.TrainType == Train.TRAINTYPE.AI_PLAYERHOSTING)
TableAddLine(table, Viewer.Catalog.GetString("Autopilot") + "???");

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