public StabilityDerivExportOutput CalculateStabilityDerivs(CelestialBody body, double alt, double machNumber, int flapSetting, bool spoilers, double alpha, double beta, double phi)
{
double pressure = body.GetPressure(alt);
double temperature = body.GetTemperature(alt);
double density = body.GetDensity(pressure, temperature);
double sspeed = body.GetSpeedOfSound(pressure, density);
double u0 = sspeed * machNumber;
double q = u0 * u0 * density * 0.5f;
StabilityDerivOutput stabDerivOutput = new StabilityDerivOutput();
StabilityDerivExportVariables stabDerivExport = new StabilityDerivExportVariables();
stabDerivOutput.nominalVelocity = u0;
stabDerivOutput.altitude = alt;
stabDerivOutput.body = body;
Vector3d CoM = Vector3d.zero;
double mass = 0;
double MAC = 0;
double b = 0;
double area = 0;
double Ix = 0;
double Iy = 0;
double Iz = 0;
double Ixy = 0;
double Iyz = 0;
double Ixz = 0;
InstantConditionSimInput input = new InstantConditionSimInput(alpha, beta, phi, 0, 0, 0, machNumber, 0, flapSetting, spoilers);
InstantConditionSimOutput nominalOutput;
InstantConditionSimOutput pertOutput = new InstantConditionSimOutput();
_instantCondition.GetClCdCmSteady(input, out nominalOutput, true);
List <Part> partsList = EditorLogic.SortedShipList;
for (int i = 0; i < partsList.Count; i++)
{
Part p = partsList[i];
if (FARAeroUtil.IsNonphysical(p))
{
continue;
}
double partMass = p.mass;
if (p.Resources.Count > 0)
{
partMass += p.GetResourceMass();
}
//partMass += p.GetModuleMass(p.mass);
// If you want to use GetModuleMass, you need to start from p.partInfo.mass, not p.mass
CoM += partMass * (Vector3d)p.transform.TransformPoint(p.CoMOffset);
mass += partMass;
FARWingAerodynamicModel w = p.GetComponent <FARWingAerodynamicModel>();
if (w != null)
{
if (w.isShielded)
{
continue;
}
area += w.S;
MAC += w.GetMAC() * w.S;
b += w.Getb_2() * w.S;
if (w is FARControllableSurface)
{
(w as FARControllableSurface).SetControlStateEditor(CoM, p.transform.up, 0, 0, 0, input.flaps, input.spoilers);
}
}
}
if (area.NearlyEqual(0))
{
area = _instantCondition._maxCrossSectionFromBody;
MAC = _instantCondition._bodyLength;
b = 1;
}
MAC /= area;
b /= area;
CoM /= mass;
mass *= 1000;
stabDerivOutput.b = b;
stabDerivOutput.MAC = MAC;
stabDerivOutput.area = area;
for (int i = 0; i < partsList.Count; i++)
{
Part p = partsList[i];
if (p == null || FARAeroUtil.IsNonphysical(p))
{
continue;
}
//This section handles the parallel axis theorem
Vector3 relPos = p.transform.TransformPoint(p.CoMOffset) - CoM;
double x2, y2, z2, x, y, z;
x2 = relPos.z * relPos.z;
y2 = relPos.x * relPos.x;
z2 = relPos.y * relPos.y;
x = relPos.z;
y = relPos.x;
z = relPos.y;
double partMass = p.mass;
if (p.Resources.Count > 0)
{
partMass += p.GetResourceMass();
}
//partMass += p.GetModuleMass(p.mass);
// If you want to use GetModuleMass, you need to start from p.partInfo.mass, not p.mass
Ix += (y2 + z2) * partMass;
Iy += (x2 + z2) * partMass;
Iz += (x2 + y2) * partMass;
Ixy += -x * y * partMass;
Iyz += -z * y * partMass;
Ixz += -x * z * partMass;
//And this handles the part's own moment of inertia
Vector3 principalInertia = p.Rigidbody.inertiaTensor;
Quaternion prncInertRot = p.Rigidbody.inertiaTensorRotation;
//The rows of the direction cosine matrix for a quaternion
Vector3 Row1 = new Vector3(prncInertRot.x * prncInertRot.x - prncInertRot.y * prncInertRot.y - prncInertRot.z * prncInertRot.z + prncInertRot.w * prncInertRot.w,
2 * (prncInertRot.x * prncInertRot.y + prncInertRot.z * prncInertRot.w),
2 * (prncInertRot.x * prncInertRot.z - prncInertRot.y * prncInertRot.w));
Vector3 Row2 = new Vector3(2 * (prncInertRot.x * prncInertRot.y - prncInertRot.z * prncInertRot.w),
-prncInertRot.x * prncInertRot.x + prncInertRot.y * prncInertRot.y - prncInertRot.z * prncInertRot.z + prncInertRot.w * prncInertRot.w,
2 * (prncInertRot.y * prncInertRot.z + prncInertRot.x * prncInertRot.w));
Vector3 Row3 = new Vector3(2 * (prncInertRot.x * prncInertRot.z + prncInertRot.y * prncInertRot.w),
2 * (prncInertRot.y * prncInertRot.z - prncInertRot.x * prncInertRot.w),
-prncInertRot.x * prncInertRot.x - prncInertRot.y * prncInertRot.y + prncInertRot.z * prncInertRot.z + prncInertRot.w * prncInertRot.w);
//And converting the principal moments of inertia into the coordinate system used by the system
Ix += principalInertia.x * Row1.x * Row1.x + principalInertia.y * Row1.y * Row1.y + principalInertia.z * Row1.z * Row1.z;
Iy += principalInertia.x * Row2.x * Row2.x + principalInertia.y * Row2.y * Row2.y + principalInertia.z * Row2.z * Row2.z;
Iz += principalInertia.x * Row3.x * Row3.x + principalInertia.y * Row3.y * Row3.y + principalInertia.z * Row3.z * Row3.z;
Ixy += principalInertia.x * Row1.x * Row2.x + principalInertia.y * Row1.y * Row2.y + principalInertia.z * Row1.z * Row2.z;
Ixz += principalInertia.x * Row1.x * Row3.x + principalInertia.y * Row1.y * Row3.y + principalInertia.z * Row1.z * Row3.z;
Iyz += principalInertia.x * Row2.x * Row3.x + principalInertia.y * Row2.y * Row3.y + principalInertia.z * Row2.z * Row3.z;
}
Ix *= 1000;
Iy *= 1000;
Iz *= 1000;
stabDerivOutput.stabDerivs[0] = Ix;
stabDerivOutput.stabDerivs[1] = Iy;
stabDerivOutput.stabDerivs[2] = Iz;
stabDerivOutput.stabDerivs[24] = Ixy;
stabDerivOutput.stabDerivs[25] = Iyz;
stabDerivOutput.stabDerivs[26] = Ixz;
double effectiveG = _instantCondition.CalculateAccelerationDueToGravity(body, alt); //This is the effect of gravity
effectiveG -= u0 * u0 / (alt + body.Radius); //This is the effective reduction of gravity due to high velocity
double neededCl = mass * effectiveG / (q * area);
_instantCondition.GetClCdCmSteady(input, out pertOutput, true, true);
//Longitudinal Mess
_instantCondition.SetState(machNumber, neededCl, CoM, 0, input.flaps, input.spoilers);
alpha = FARMathUtil.SelectedSearchMethod(machNumber, _instantCondition.FunctionIterateForAlpha);
input.alpha = alpha;
nominalOutput = _instantCondition.iterationOutput;
//alpha_str = (alpha * Mathf.PI / 180).ToString();
input.alpha = (alpha + 2);
_instantCondition.GetClCdCmSteady(input, out pertOutput, true, true);
stabDerivOutput.stableCl = neededCl;
stabDerivOutput.stableCd = nominalOutput.Cd;
stabDerivOutput.stableAoA = alpha;
stabDerivOutput.stableAoAState = "";
if (Math.Abs((nominalOutput.Cl - neededCl) / neededCl) > 0.1)
{
stabDerivOutput.stableAoAState = ((nominalOutput.Cl > neededCl) ? "<" : ">");
}
FARLogger.Info("Cl needed: " + neededCl + ", AoA: " + alpha + ", Cl: " + nominalOutput.Cl + ", Cd: " + nominalOutput.Cd);
pertOutput.Cl = (pertOutput.Cl - nominalOutput.Cl) / (2 * FARMathUtil.deg2rad); //vert vel derivs
pertOutput.Cd = (pertOutput.Cd - nominalOutput.Cd) / (2 * FARMathUtil.deg2rad);
pertOutput.Cm = (pertOutput.Cm - nominalOutput.Cm) / (2 * FARMathUtil.deg2rad);
pertOutput.Cl += nominalOutput.Cd;
pertOutput.Cd -= nominalOutput.Cl;
pertOutput.Cl *= -q * area / (mass * u0);
pertOutput.Cd *= -q * area / (mass * u0);
pertOutput.Cm *= q * area * MAC / (Iy * u0);
stabDerivOutput.stabDerivs[3] = pertOutput.Cl; //Zw
stabDerivOutput.stabDerivs[4] = pertOutput.Cd; //Xw
stabDerivOutput.stabDerivs[5] = pertOutput.Cm; //Mw
// Rodhern: The motivation for the revised stability derivatives sign interpretations of Zq, Xq, Ze and Xe
// is to align the sign conventions used for Zu, Zq, Ze, Xu, Xq and Xe. Further explanation can be found
// here: https://forum.kerbalspaceprogram.com/index.php?/topic/109098-official-far-craft-repository/&do=findComment&comment=2425057
input.alpha = alpha;
input.machNumber = machNumber + 0.05;
_instantCondition.GetClCdCmSteady(input, out pertOutput, true, false);
pertOutput.Cl = (pertOutput.Cl - nominalOutput.Cl) / 0.05 * machNumber; //fwd vel derivs
pertOutput.Cd = (pertOutput.Cd - nominalOutput.Cd) / 0.05 * machNumber;
pertOutput.Cm = (pertOutput.Cm - nominalOutput.Cm) / 0.05 * machNumber;
pertOutput.Cl += 2 * nominalOutput.Cl;
pertOutput.Cd += 2 * nominalOutput.Cd;
pertOutput.Cl *= -q * area / (mass * u0);
pertOutput.Cd *= -q * area / (mass * u0);
pertOutput.Cm *= q * area * MAC / (u0 * Iy);
stabDerivOutput.stabDerivs[6] = pertOutput.Cl; //Zu
stabDerivOutput.stabDerivs[7] = pertOutput.Cd; //Xu
stabDerivOutput.stabDerivs[8] = pertOutput.Cm; //Mu
input.machNumber = machNumber;
_instantCondition.GetClCdCmSteady(input, out pertOutput, true, true);
input.alphaDot = -0.05;
_instantCondition.GetClCdCmSteady(input, out pertOutput, true, false);
pertOutput.Cl = (pertOutput.Cl - nominalOutput.Cl) / 0.05; //pitch rate derivs
pertOutput.Cd = (pertOutput.Cd - nominalOutput.Cd) / 0.05;
pertOutput.Cm = (pertOutput.Cm - nominalOutput.Cm) / 0.05;
pertOutput.Cl *= -q * area * MAC / (2 * u0 * mass); // Rodhern: Replaced 'q' by '-q', so that formulas
pertOutput.Cd *= -q * area * MAC / (2 * u0 * mass); // for Zq and Xq match those for Zu and Xu.
pertOutput.Cm *= q * area * MAC * MAC / (2 * u0 * Iy);
stabDerivOutput.stabDerivs[9] = pertOutput.Cl; //Zq
stabDerivOutput.stabDerivs[10] = pertOutput.Cd; //Xq
stabDerivOutput.stabDerivs[11] = pertOutput.Cm; //Mq
input.alphaDot = 0;
input.pitchValue = 0.1;
_instantCondition.GetClCdCmSteady(input, out pertOutput, true, false);
pertOutput.Cl = (pertOutput.Cl - nominalOutput.Cl) / 0.1; //elevator derivs
pertOutput.Cd = (pertOutput.Cd - nominalOutput.Cd) / 0.1;
pertOutput.Cm = (pertOutput.Cm - nominalOutput.Cm) / 0.1;
pertOutput.Cl *= -q * area / mass; // Rodhern: Replaced 'q' by '-q', so that formulas
pertOutput.Cd *= -q * area / mass; // for Ze and Xe match those for Zu and Xu.
pertOutput.Cm *= q * area * MAC / Iy;
stabDerivOutput.stabDerivs[12] = pertOutput.Cl; //Ze
stabDerivOutput.stabDerivs[13] = pertOutput.Cd; //Xe
stabDerivOutput.stabDerivs[14] = pertOutput.Cm; //Me
//Lateral Mess
input.pitchValue = 0;
input.beta = (beta + 2);
_instantCondition.GetClCdCmSteady(input, out pertOutput, true, false);
pertOutput.Cy = (pertOutput.Cy - nominalOutput.Cy) / (2 * FARMathUtil.deg2rad); //sideslip angle derivs
pertOutput.Cn = (pertOutput.Cn - nominalOutput.Cn) / (2 * FARMathUtil.deg2rad);
pertOutput.C_roll = (pertOutput.C_roll - nominalOutput.C_roll) / (2 * FARMathUtil.deg2rad);
pertOutput.Cy *= q * area / mass;
pertOutput.Cn *= q * area * b / Iz;
pertOutput.C_roll *= q * area * b / Ix;
stabDerivOutput.stabDerivs[15] = pertOutput.Cy; //Yb
stabDerivOutput.stabDerivs[17] = pertOutput.Cn; //Nb
stabDerivOutput.stabDerivs[16] = pertOutput.C_roll; //Lb
input.beta = beta;
_instantCondition.GetClCdCmSteady(input, out pertOutput, true, true);
input.phiDot = -0.05;
_instantCondition.GetClCdCmSteady(input, out pertOutput, true, false);
pertOutput.Cy = (pertOutput.Cy - nominalOutput.Cy) / 0.05; //roll rate derivs
pertOutput.Cn = (pertOutput.Cn - nominalOutput.Cn) / 0.05;
pertOutput.C_roll = (pertOutput.C_roll - nominalOutput.C_roll) / 0.05;
pertOutput.Cy *= q * area * b / (2 * mass * u0);
pertOutput.Cn *= q * area * b * b / (2 * Iz * u0);
pertOutput.C_roll *= q * area * b * b / (2 * Ix * u0);
stabDerivOutput.stabDerivs[18] = pertOutput.Cy; //Yp
stabDerivOutput.stabDerivs[20] = pertOutput.Cn; //Np
stabDerivOutput.stabDerivs[19] = pertOutput.C_roll; //Lp
input.phiDot = 0;
_instantCondition.GetClCdCmSteady(input, out pertOutput, true, true);
input.betaDot = -0.05;
_instantCondition.GetClCdCmSteady(input, out pertOutput, true, false); pertOutput.Cy = (pertOutput.Cy - nominalOutput.Cy) / 0.05f; //yaw rate derivs
pertOutput.Cn = (pertOutput.Cn - nominalOutput.Cn) / 0.05f;
pertOutput.C_roll = (pertOutput.C_roll - nominalOutput.C_roll) / 0.05f;
pertOutput.Cy *= q * area * b / (2 * mass * u0);
pertOutput.Cn *= q * area * b * b / (2 * Iz * u0);
pertOutput.C_roll *= q * area * b * b / (2 * Ix * u0);
stabDerivOutput.stabDerivs[21] = pertOutput.Cy; //Yr
stabDerivOutput.stabDerivs[23] = pertOutput.Cn; //Nr
stabDerivOutput.stabDerivs[22] = pertOutput.C_roll; //Lr
// Assign values to export variables
stabDerivExport.craftmass = mass;
stabDerivExport.envpressure = pressure;
stabDerivExport.envtemperature = temperature;
stabDerivExport.envdensity = density;
stabDerivExport.envsoundspeed = sspeed;
stabDerivExport.envg = _instantCondition.CalculateAccelerationDueToGravity(body, alt);
stabDerivExport.sitmach = machNumber;
stabDerivExport.sitdynpres = q;
stabDerivExport.siteffg = effectiveG;
return(new StabilityDerivExportOutput(stabDerivOutput, stabDerivExport));
}
public StabilityDerivOutput CalculateStabilityDerivs(double u0, double q, double machNumber, double alpha, double beta, double phi, int flapSetting, bool spoilers, CelestialBody body, double alt)
{
StabilityDerivOutput stabDerivOutput = new StabilityDerivOutput();
stabDerivOutput.nominalVelocity = u0;
stabDerivOutput.altitude = alt;
stabDerivOutput.body = body;
Vector3d CoM = Vector3d.zero;
double mass = 0;
double MAC = 0;
double b = 0;
double area = 0;
double Ix = 0;
double Iy = 0;
double Iz = 0;
double Ixy = 0;
double Iyz = 0;
double Ixz = 0;
InstantConditionSimInput input = new InstantConditionSimInput(alpha, beta, phi, 0, 0, 0, machNumber, 0, flapSetting, spoilers);
InstantConditionSimOutput nominalOutput;
InstantConditionSimOutput pertOutput = new InstantConditionSimOutput();
_instantCondition.GetClCdCmSteady(input, out nominalOutput, true);
List <Part> partsList = EditorLogic.SortedShipList;
for (int i = 0; i < partsList.Count; i++)
{
Part p = partsList[i];
if (FARAeroUtil.IsNonphysical(p))
{
continue;
}
double partMass = p.mass;
if (p.Resources.Count > 0)
{
partMass += p.GetResourceMass();
}
//partMass += p.GetModuleMass(p.mass);
// If you want to use GetModuleMass, you need to start from p.partInfo.mass, not p.mass
CoM += partMass * (Vector3d)p.transform.TransformPoint(p.CoMOffset);
mass += partMass;
FARWingAerodynamicModel w = p.GetComponent <FARWingAerodynamicModel>();
if (w != null)
{
if (w.isShielded)
{
continue;
}
area += w.S;
MAC += w.GetMAC() * w.S;
b += w.Getb_2() * w.S;
if (w is FARControllableSurface)
{
(w as FARControllableSurface).SetControlStateEditor(CoM, p.transform.up, 0, 0, 0, input.flaps, input.spoilers);
}
}
}
if (area == 0)
{
area = _instantCondition._maxCrossSectionFromBody;
MAC = _instantCondition._bodyLength;
b = 1;
}
MAC /= area;
b /= area;
CoM /= mass;
mass *= 1000;
stabDerivOutput.b = b;
stabDerivOutput.MAC = MAC;
stabDerivOutput.area = area;
for (int i = 0; i < partsList.Count; i++)
{
Part p = partsList[i];
if (p == null || FARAeroUtil.IsNonphysical(p))
{
continue;
}
//This section handles the parallel axis theorem
Vector3 relPos = p.transform.TransformPoint(p.CoMOffset) - CoM;
double x2, y2, z2, x, y, z;
x2 = relPos.z * relPos.z;
y2 = relPos.x * relPos.x;
z2 = relPos.y * relPos.y;
x = relPos.z;
y = relPos.x;
z = relPos.y;
double partMass = p.mass;
if (p.Resources.Count > 0)
{
partMass += p.GetResourceMass();
}
//partMass += p.GetModuleMass(p.mass);
// If you want to use GetModuleMass, you need to start from p.partInfo.mass, not p.mass
Ix += (y2 + z2) * partMass;
Iy += (x2 + z2) * partMass;
Iz += (x2 + y2) * partMass;
Ixy += -x * y * partMass;
Iyz += -z * y * partMass;
Ixz += -x * z * partMass;
//And this handles the part's own moment of inertia
Vector3 principalInertia = p.Rigidbody.inertiaTensor;
Quaternion prncInertRot = p.Rigidbody.inertiaTensorRotation;
//The rows of the direction cosine matrix for a quaternion
Vector3 Row1 = new Vector3(prncInertRot.x * prncInertRot.x - prncInertRot.y * prncInertRot.y - prncInertRot.z * prncInertRot.z + prncInertRot.w * prncInertRot.w,
2 * (prncInertRot.x * prncInertRot.y + prncInertRot.z * prncInertRot.w),
2 * (prncInertRot.x * prncInertRot.z - prncInertRot.y * prncInertRot.w));
Vector3 Row2 = new Vector3(2 * (prncInertRot.x * prncInertRot.y - prncInertRot.z * prncInertRot.w),
-prncInertRot.x * prncInertRot.x + prncInertRot.y * prncInertRot.y - prncInertRot.z * prncInertRot.z + prncInertRot.w * prncInertRot.w,
2 * (prncInertRot.y * prncInertRot.z + prncInertRot.x * prncInertRot.w));
Vector3 Row3 = new Vector3(2 * (prncInertRot.x * prncInertRot.z + prncInertRot.y * prncInertRot.w),
2 * (prncInertRot.y * prncInertRot.z - prncInertRot.x * prncInertRot.w),
-prncInertRot.x * prncInertRot.x - prncInertRot.y * prncInertRot.y + prncInertRot.z * prncInertRot.z + prncInertRot.w * prncInertRot.w);
//And converting the principal moments of inertia into the coordinate system used by the system
Ix += principalInertia.x * Row1.x * Row1.x + principalInertia.y * Row1.y * Row1.y + principalInertia.z * Row1.z * Row1.z;
Iy += principalInertia.x * Row2.x * Row2.x + principalInertia.y * Row2.y * Row2.y + principalInertia.z * Row2.z * Row2.z;
Iz += principalInertia.x * Row3.x * Row3.x + principalInertia.y * Row3.y * Row3.y + principalInertia.z * Row3.z * Row3.z;
Ixy += principalInertia.x * Row1.x * Row2.x + principalInertia.y * Row1.y * Row2.y + principalInertia.z * Row1.z * Row2.z;
Ixz += principalInertia.x * Row1.x * Row3.x + principalInertia.y * Row1.y * Row3.y + principalInertia.z * Row1.z * Row3.z;
Iyz += principalInertia.x * Row2.x * Row3.x + principalInertia.y * Row2.y * Row3.y + principalInertia.z * Row2.z * Row3.z;
}
Ix *= 1000;
Iy *= 1000;
Iz *= 1000;
stabDerivOutput.stabDerivs[0] = Ix;
stabDerivOutput.stabDerivs[1] = Iy;
stabDerivOutput.stabDerivs[2] = Iz;
stabDerivOutput.stabDerivs[24] = Ixy;
stabDerivOutput.stabDerivs[25] = Iyz;
stabDerivOutput.stabDerivs[26] = Ixz;
double effectiveG = _instantCondition.CalculateAccelerationDueToGravity(body, alt); //This is the effect of gravity
effectiveG -= u0 * u0 / (alt + body.Radius); //This is the effective reduction of gravity due to high velocity
double neededCl = mass * effectiveG / (q * area);
_instantCondition.GetClCdCmSteady(input, out pertOutput, true, true);
//Longitudinal Mess
_instantCondition.SetState(machNumber, neededCl, CoM, 0, input.flaps, input.spoilers);
alpha = FARMathUtil.BrentsMethod(_instantCondition.FunctionIterateForAlpha, -30d, 30d, 0.001, 500);
input.alpha = alpha;
nominalOutput = _instantCondition.iterationOutput;
//alpha_str = (alpha * Mathf.PI / 180).ToString();
input.alpha = (alpha + 2);
_instantCondition.GetClCdCmSteady(input, out pertOutput, true, true);
stabDerivOutput.stableCl = neededCl;
stabDerivOutput.stableCd = nominalOutput.Cd;
stabDerivOutput.stableAoA = alpha;
stabDerivOutput.stableAoAState = "";
if (Math.Abs((nominalOutput.Cl - neededCl) / neededCl) > 0.1)
{
stabDerivOutput.stableAoAState = ((nominalOutput.Cl > neededCl) ? "<" : ">");
}
Debug.Log("Cl needed: " + neededCl + ", AoA: " + alpha + ", Cl: " + nominalOutput.Cl + ", Cd: " + nominalOutput.Cd);
pertOutput.Cl = (pertOutput.Cl - nominalOutput.Cl) / (2 * FARMathUtil.deg2rad); //vert vel derivs
pertOutput.Cd = (pertOutput.Cd - nominalOutput.Cd) / (2 * FARMathUtil.deg2rad);
pertOutput.Cm = (pertOutput.Cm - nominalOutput.Cm) / (2 * FARMathUtil.deg2rad);
pertOutput.Cl += nominalOutput.Cd;
pertOutput.Cd -= nominalOutput.Cl;
pertOutput.Cl *= -q * area / (mass * u0);
pertOutput.Cd *= -q * area / (mass * u0);
pertOutput.Cm *= q * area * MAC / (Iy * u0);
stabDerivOutput.stabDerivs[3] = pertOutput.Cl; //Zw
stabDerivOutput.stabDerivs[4] = pertOutput.Cd; //Xw
stabDerivOutput.stabDerivs[5] = pertOutput.Cm; //Mw
input.alpha = alpha;
input.machNumber = machNumber + 0.05;
_instantCondition.GetClCdCmSteady(input, out pertOutput, true, false);
pertOutput.Cl = (pertOutput.Cl - nominalOutput.Cl) / 0.05 * machNumber; //fwd vel derivs
pertOutput.Cd = (pertOutput.Cd - nominalOutput.Cd) / 0.05 * machNumber;
pertOutput.Cm = (pertOutput.Cm - nominalOutput.Cm) / 0.05 * machNumber;
pertOutput.Cl += 2 * nominalOutput.Cl;
pertOutput.Cd += 2 * nominalOutput.Cd;
pertOutput.Cl *= -q * area / (mass * u0);
pertOutput.Cd *= -q * area / (mass * u0);
pertOutput.Cm *= q * area * MAC / (u0 * Iy);
stabDerivOutput.stabDerivs[6] = pertOutput.Cl; //Zu
stabDerivOutput.stabDerivs[7] = pertOutput.Cd; //Xu
stabDerivOutput.stabDerivs[8] = pertOutput.Cm; //Mu
input.machNumber = machNumber;
_instantCondition.GetClCdCmSteady(input, out pertOutput, true, true);
input.alphaDot = -0.05;
_instantCondition.GetClCdCmSteady(input, out pertOutput, true, false);
pertOutput.Cl = (pertOutput.Cl - nominalOutput.Cl) / 0.05; //pitch rate derivs
pertOutput.Cd = (pertOutput.Cd - nominalOutput.Cd) / 0.05;
pertOutput.Cm = (pertOutput.Cm - nominalOutput.Cm) / 0.05;
pertOutput.Cl *= q * area * MAC / (2 * u0 * mass);
pertOutput.Cd *= q * area * MAC / (2 * u0 * mass);
pertOutput.Cm *= q * area * MAC * MAC / (2 * u0 * Iy);
stabDerivOutput.stabDerivs[9] = pertOutput.Cl; //Zq
stabDerivOutput.stabDerivs[10] = pertOutput.Cd; //Xq
stabDerivOutput.stabDerivs[11] = pertOutput.Cm; //Mq
input.alphaDot = 0;
input.pitchValue = 0.1;
_instantCondition.GetClCdCmSteady(input, out pertOutput, true, false);
pertOutput.Cl = (pertOutput.Cl - nominalOutput.Cl) / 0.1; //elevator derivs
pertOutput.Cd = (pertOutput.Cd - nominalOutput.Cd) / 0.1;
pertOutput.Cm = (pertOutput.Cm - nominalOutput.Cm) / 0.1;
pertOutput.Cl *= q * area / mass;
pertOutput.Cd *= q * area / mass;
pertOutput.Cm *= q * area * MAC / Iy;
stabDerivOutput.stabDerivs[12] = pertOutput.Cl; //Ze
stabDerivOutput.stabDerivs[13] = pertOutput.Cd; //Xe
stabDerivOutput.stabDerivs[14] = pertOutput.Cm; //Me
//Lateral Mess
input.pitchValue = 0;
input.beta = (beta + 2);
_instantCondition.GetClCdCmSteady(input, out pertOutput, true, false);
pertOutput.Cy = (pertOutput.Cy - nominalOutput.Cy) / (2 * FARMathUtil.deg2rad); //sideslip angle derivs
pertOutput.Cn = (pertOutput.Cn - nominalOutput.Cn) / (2 * FARMathUtil.deg2rad);
pertOutput.C_roll = (pertOutput.C_roll - nominalOutput.C_roll) / (2 * FARMathUtil.deg2rad);
pertOutput.Cy *= q * area / mass;
pertOutput.Cn *= q * area * b / Iz;
pertOutput.C_roll *= q * area * b / Ix;
stabDerivOutput.stabDerivs[15] = pertOutput.Cy; //Yb
stabDerivOutput.stabDerivs[17] = pertOutput.Cn; //Nb
stabDerivOutput.stabDerivs[16] = pertOutput.C_roll; //Lb
input.beta = beta;
_instantCondition.GetClCdCmSteady(input, out pertOutput, true, true);
input.phiDot = -0.05;
_instantCondition.GetClCdCmSteady(input, out pertOutput, true, false);
pertOutput.Cy = (pertOutput.Cy - nominalOutput.Cy) / 0.05; //roll rate derivs
pertOutput.Cn = (pertOutput.Cn - nominalOutput.Cn) / 0.05;
pertOutput.C_roll = (pertOutput.C_roll - nominalOutput.C_roll) / 0.05;
pertOutput.Cy *= q * area * b / (2 * mass * u0);
pertOutput.Cn *= q * area * b * b / (2 * Iz * u0);
pertOutput.C_roll *= q * area * b * b / (2 * Ix * u0);
stabDerivOutput.stabDerivs[18] = pertOutput.Cy; //Yp
stabDerivOutput.stabDerivs[20] = pertOutput.Cn; //Np
stabDerivOutput.stabDerivs[19] = pertOutput.C_roll; //Lp
input.phiDot = 0;
_instantCondition.GetClCdCmSteady(input, out pertOutput, true, true);
input.betaDot = -0.05;
_instantCondition.GetClCdCmSteady(input, out pertOutput, true, false); pertOutput.Cy = (pertOutput.Cy - nominalOutput.Cy) / 0.05f; //yaw rate derivs
pertOutput.Cn = (pertOutput.Cn - nominalOutput.Cn) / 0.05f;
pertOutput.C_roll = (pertOutput.C_roll - nominalOutput.C_roll) / 0.05f;
pertOutput.Cy *= q * area * b / (2 * mass * u0);
pertOutput.Cn *= q * area * b * b / (2 * Iz * u0);
pertOutput.C_roll *= q * area * b * b / (2 * Ix * u0);
stabDerivOutput.stabDerivs[21] = pertOutput.Cy; //Yr
stabDerivOutput.stabDerivs[23] = pertOutput.Cn; //Nr
stabDerivOutput.stabDerivs[22] = pertOutput.C_roll; //Lr
return(stabDerivOutput);
}
public StabilityDerivOutput CalculateStabilityDerivs(
CelestialBody body,
double alt,
double machNumber,
int flapSetting,
bool spoilers,
double alpha,
double beta,
double phi
)
{
GasProperties properties = FARAtmosphere.GetGasProperties(body,
new Vector3d(0, 0, alt),
Planetarium.GetUniversalTime());
double pressure = properties.Pressure;
double temperature = properties.Temperature;
double density = properties.Density;
double sspeed = properties.SpeedOfSound;
double u0 = sspeed * machNumber;
double q = u0 * u0 * density * 0.5f;
var stabDerivOutput = new StabilityDerivOutput
{
nominalVelocity = u0,
altitude = alt,
body = body
};
Vector3d CoM = Vector3d.zero;
double mass = 0;
double MAC = 0;
double b = 0;
double area = 0;
double Ix = 0;
double Iy = 0;
double Iz = 0;
double Ixy = 0;
double Iyz = 0;
double Ixz = 0;
var input = new InstantConditionSimInput(alpha, beta, phi, 0, 0, 0, machNumber, 0, flapSetting, spoilers);
var pertOutput = new InstantConditionSimOutput();
_instantCondition.GetClCdCmSteady(input, out InstantConditionSimOutput nominalOutput, true);
List <Part> partsList = EditorLogic.SortedShipList;
foreach (Part p in partsList)
{
if (FARAeroUtil.IsNonphysical(p))
{
continue;
}
double partMass = p.mass;
if (p.Resources.Count > 0)
{
partMass += p.GetResourceMass();
}
// If you want to use GetModuleMass, you need to start from p.partInfo.mass, not p.mass
CoM += partMass * (Vector3d)p.transform.TransformPoint(p.CoMOffset);
mass += partMass;
FARWingAerodynamicModel w = p.GetComponent <FARWingAerodynamicModel>();
if (w == null)
{
continue;
}
if (w.isShielded)
{
continue;
}
area += w.S;
MAC += w.GetMAC() * w.S;
b += w.Getb_2() * w.S;
if (w is FARControllableSurface controllableSurface)
{
controllableSurface.SetControlStateEditor(CoM,
p.transform.up,
0,
0,
0,
input.flaps,
input.spoilers);
}
}
if (area.NearlyEqual(0))
{
area = _instantCondition._maxCrossSectionFromBody;
MAC = _instantCondition._bodyLength;
b = 1;
}
MAC /= area;
b /= area;
CoM /= mass;
mass *= 1000;
stabDerivOutput.b = b;
stabDerivOutput.MAC = MAC;
stabDerivOutput.area = area;
foreach (Part p in partsList)
{
if (p == null || FARAeroUtil.IsNonphysical(p))
{
continue;
}
//This section handles the parallel axis theorem
Vector3 relPos = p.transform.TransformPoint(p.CoMOffset) - CoM;
double x2 = relPos.z * relPos.z;
double y2 = relPos.x * relPos.x;
double z2 = relPos.y * relPos.y;
double x = relPos.z;
double y = relPos.x;
double z = relPos.y;
double partMass = p.mass;
if (p.Resources.Count > 0)
{
partMass += p.GetResourceMass();
}
// If you want to use GetModuleMass, you need to start from p.partInfo.mass, not p.mass
Ix += (y2 + z2) * partMass;
Iy += (x2 + z2) * partMass;
Iz += (x2 + y2) * partMass;
Ixy += -x * y * partMass;
Iyz += -z * y * partMass;
Ixz += -x * z * partMass;
//And this handles the part's own moment of inertia
Vector3 principalInertia = p.Rigidbody.inertiaTensor;
Quaternion prncInertRot = p.Rigidbody.inertiaTensorRotation;
//The rows of the direction cosine matrix for a quaternion
var Row1 =
new Vector3(prncInertRot.x * prncInertRot.x -
prncInertRot.y * prncInertRot.y -
prncInertRot.z * prncInertRot.z +
prncInertRot.w * prncInertRot.w,
2 * (prncInertRot.x * prncInertRot.y + prncInertRot.z * prncInertRot.w),
2 * (prncInertRot.x * prncInertRot.z - prncInertRot.y * prncInertRot.w));
var Row2 = new Vector3(2 * (prncInertRot.x * prncInertRot.y - prncInertRot.z * prncInertRot.w),
-prncInertRot.x * prncInertRot.x +
prncInertRot.y * prncInertRot.y -
prncInertRot.z * prncInertRot.z +
prncInertRot.w * prncInertRot.w,
2 * (prncInertRot.y * prncInertRot.z + prncInertRot.x * prncInertRot.w));
var Row3 = new Vector3(2 * (prncInertRot.x * prncInertRot.z + prncInertRot.y * prncInertRot.w),
2 * (prncInertRot.y * prncInertRot.z - prncInertRot.x * prncInertRot.w),
-prncInertRot.x * prncInertRot.x -
prncInertRot.y * prncInertRot.y +
prncInertRot.z * prncInertRot.z +
prncInertRot.w * prncInertRot.w);
//And converting the principal moments of inertia into the coordinate system used by the system
Ix += principalInertia.x * Row1.x * Row1.x +
principalInertia.y * Row1.y * Row1.y +
principalInertia.z * Row1.z * Row1.z;
Iy += principalInertia.x * Row2.x * Row2.x +
principalInertia.y * Row2.y * Row2.y +
principalInertia.z * Row2.z * Row2.z;
Iz += principalInertia.x * Row3.x * Row3.x +
principalInertia.y * Row3.y * Row3.y +
principalInertia.z * Row3.z * Row3.z;
Ixy += principalInertia.x * Row1.x * Row2.x +
principalInertia.y * Row1.y * Row2.y +
principalInertia.z * Row1.z * Row2.z;
Ixz += principalInertia.x * Row1.x * Row3.x +
principalInertia.y * Row1.y * Row3.y +
principalInertia.z * Row1.z * Row3.z;
Iyz += principalInertia.x * Row2.x * Row3.x +
principalInertia.y * Row2.y * Row3.y +
principalInertia.z * Row2.z * Row3.z;
}
Ix *= 1000;
Iy *= 1000;
Iz *= 1000;
stabDerivOutput.stabDerivs[0] = Ix;
stabDerivOutput.stabDerivs[1] = Iy;
stabDerivOutput.stabDerivs[2] = Iz;
stabDerivOutput.stabDerivs[24] = Ixy;
stabDerivOutput.stabDerivs[25] = Iyz;
stabDerivOutput.stabDerivs[26] = Ixz;
//This is the effect of gravity
double effectiveG = InstantConditionSim.CalculateAccelerationDueToGravity(body, alt);
//This is the effective reduction of gravity due to high velocity
effectiveG -= u0 * u0 / (alt + body.Radius);
double neededCl = mass * effectiveG / (q * area);
_instantCondition.GetClCdCmSteady(input, out pertOutput, true, true);
//Longitudinal Mess
_instantCondition.SetState(machNumber, neededCl, CoM, 0, input.flaps, input.spoilers);
FARMathUtil.OptimizationResult optResult =
FARMathUtil.Secant(_instantCondition.FunctionIterateForAlpha,
0,
10,
1e-4,
1e-4,
minLimit: -90,
maxLimit: 90);
int calls = optResult.FunctionCalls;
// if stable AoA doesn't exist, calculate derivatives at 0 incidence
if (!optResult.Converged)
{
FARLogger.Info("Stable angle of attack not found, calculating derivatives at 0 incidence instead");
alpha = 0;
_instantCondition.FunctionIterateForAlpha(alpha);
calls += 1;
}
else
{
alpha = optResult.Result;
}
input.alpha = alpha;
nominalOutput = _instantCondition.iterationOutput;
input.alpha = alpha + 2;
_instantCondition.GetClCdCmSteady(input, out pertOutput, true, true);
stabDerivOutput.stableCl = neededCl;
stabDerivOutput.stableCd = nominalOutput.Cd;
stabDerivOutput.stableAoA = alpha;
stabDerivOutput.stableAoAState = "";
if (Math.Abs((nominalOutput.Cl - neededCl) / neededCl) > 0.1)
{
stabDerivOutput.stableAoAState = nominalOutput.Cl > neededCl ? "<" : ">";
}
FARLogger.Info("Cl needed: " +
neededCl.ToString(CultureInfo.InvariantCulture) +
", AoA: " +
stabDerivOutput.stableAoA.ToString(CultureInfo.InvariantCulture) +
", Cl: " +
nominalOutput.Cl.ToString(CultureInfo.InvariantCulture) +
", Cd: " +
nominalOutput.Cd.ToString(CultureInfo.InvariantCulture) +
", function calls: " +
calls.ToString());
//vert vel derivs
pertOutput.Cl = (pertOutput.Cl - nominalOutput.Cl) / (2 * FARMathUtil.deg2rad);
pertOutput.Cd = (pertOutput.Cd - nominalOutput.Cd) / (2 * FARMathUtil.deg2rad);
pertOutput.Cm = (pertOutput.Cm - nominalOutput.Cm) / (2 * FARMathUtil.deg2rad);
pertOutput.Cl += nominalOutput.Cd;
pertOutput.Cd -= nominalOutput.Cl;
pertOutput.Cl *= -q * area / (mass * u0);
pertOutput.Cd *= -q * area / (mass * u0);
pertOutput.Cm *= q * area * MAC / (Iy * u0);
stabDerivOutput.stabDerivs[3] = pertOutput.Cl; //Zw
stabDerivOutput.stabDerivs[4] = pertOutput.Cd; //Xw
stabDerivOutput.stabDerivs[5] = pertOutput.Cm; //Mw
// Rodhern: The motivation for the revised stability derivatives sign interpretations of Zq, Xq, Ze and Xe
// is to align the sign conventions used for Zu, Zq, Ze, Xu, Xq and Xe. Further explanation can be found
// here: https://forum.kerbalspaceprogram.com/index.php?/topic/109098-official-far-craft-repository/&do=findComment&comment=2425057
input.alpha = alpha;
input.machNumber = machNumber + 0.05;
_instantCondition.GetClCdCmSteady(input, out pertOutput, true);
//fwd vel derivs
pertOutput.Cl = (pertOutput.Cl - nominalOutput.Cl) / 0.05 * machNumber;
pertOutput.Cd = (pertOutput.Cd - nominalOutput.Cd) / 0.05 * machNumber;
pertOutput.Cm = (pertOutput.Cm - nominalOutput.Cm) / 0.05 * machNumber;
pertOutput.Cl += 2 * nominalOutput.Cl;
pertOutput.Cd += 2 * nominalOutput.Cd;
pertOutput.Cl *= -q * area / (mass * u0);
pertOutput.Cd *= -q * area / (mass * u0);
pertOutput.Cm *= q * area * MAC / (u0 * Iy);
stabDerivOutput.stabDerivs[6] = pertOutput.Cl; //Zu
stabDerivOutput.stabDerivs[7] = pertOutput.Cd; //Xu
stabDerivOutput.stabDerivs[8] = pertOutput.Cm; //Mu
input.machNumber = machNumber;
_instantCondition.GetClCdCmSteady(input, out pertOutput, true, true);
input.alphaDot = -0.05;
_instantCondition.GetClCdCmSteady(input, out pertOutput, true);
//pitch rate derivs
pertOutput.Cl = (pertOutput.Cl - nominalOutput.Cl) / 0.05;
pertOutput.Cd = (pertOutput.Cd - nominalOutput.Cd) / 0.05;
pertOutput.Cm = (pertOutput.Cm - nominalOutput.Cm) / 0.05;
pertOutput.Cl *= -q * area * MAC / (2 * u0 * mass); // Rodhern: Replaced 'q' by '-q', so that formulas
pertOutput.Cd *= -q * area * MAC / (2 * u0 * mass); // for Zq and Xq match those for Zu and Xu.
pertOutput.Cm *= q * area * MAC * MAC / (2 * u0 * Iy);
stabDerivOutput.stabDerivs[9] = pertOutput.Cl; //Zq
stabDerivOutput.stabDerivs[10] = pertOutput.Cd; //Xq
stabDerivOutput.stabDerivs[11] = pertOutput.Cm; //Mq
input.alphaDot = 0;
input.pitchValue = 0.1;
_instantCondition.GetClCdCmSteady(input, out pertOutput, true);
//elevator derivs
pertOutput.Cl = (pertOutput.Cl - nominalOutput.Cl) / 0.1;
pertOutput.Cd = (pertOutput.Cd - nominalOutput.Cd) / 0.1;
pertOutput.Cm = (pertOutput.Cm - nominalOutput.Cm) / 0.1;
pertOutput.Cl *= -q * area / mass; // Rodhern: Replaced 'q' by '-q', so that formulas
pertOutput.Cd *= -q * area / mass; // for Ze and Xe match those for Zu and Xu.
pertOutput.Cm *= q * area * MAC / Iy;
stabDerivOutput.stabDerivs[12] = pertOutput.Cl; //Ze
stabDerivOutput.stabDerivs[13] = pertOutput.Cd; //Xe
stabDerivOutput.stabDerivs[14] = pertOutput.Cm; //Me
//Lateral Mess
input.pitchValue = 0;
input.beta = beta + 2;
_instantCondition.GetClCdCmSteady(input, out pertOutput, true);
//sideslip angle derivs
pertOutput.Cy = (pertOutput.Cy - nominalOutput.Cy) / (2 * FARMathUtil.deg2rad);
pertOutput.Cn = (pertOutput.Cn - nominalOutput.Cn) / (2 * FARMathUtil.deg2rad);
pertOutput.C_roll = (pertOutput.C_roll - nominalOutput.C_roll) / (2 * FARMathUtil.deg2rad);
pertOutput.Cy *= q * area / mass;
pertOutput.Cn *= q * area * b / Iz;
pertOutput.C_roll *= q * area * b / Ix;
stabDerivOutput.stabDerivs[15] = pertOutput.Cy; //Yb
stabDerivOutput.stabDerivs[17] = pertOutput.Cn; //Nb
stabDerivOutput.stabDerivs[16] = pertOutput.C_roll; //Lb
input.beta = beta;
_instantCondition.GetClCdCmSteady(input, out pertOutput, true, true);
input.phiDot = -0.05;
_instantCondition.GetClCdCmSteady(input, out pertOutput, true);
//roll rate derivs
pertOutput.Cy = (pertOutput.Cy - nominalOutput.Cy) / 0.05;
pertOutput.Cn = (pertOutput.Cn - nominalOutput.Cn) / 0.05;
pertOutput.C_roll = (pertOutput.C_roll - nominalOutput.C_roll) / 0.05;
pertOutput.Cy *= q * area * b / (2 * mass * u0);
pertOutput.Cn *= q * area * b * b / (2 * Iz * u0);
pertOutput.C_roll *= q * area * b * b / (2 * Ix * u0);
stabDerivOutput.stabDerivs[18] = pertOutput.Cy; //Yp
stabDerivOutput.stabDerivs[20] = pertOutput.Cn; //Np
stabDerivOutput.stabDerivs[19] = pertOutput.C_roll; //Lp
input.phiDot = 0;
_instantCondition.GetClCdCmSteady(input, out pertOutput, true, true);
input.betaDot = -0.05;
//yaw rate derivs
_instantCondition.GetClCdCmSteady(input, out pertOutput, true);
pertOutput.Cy = (pertOutput.Cy - nominalOutput.Cy) / 0.05f;
pertOutput.Cn = (pertOutput.Cn - nominalOutput.Cn) / 0.05f;
pertOutput.C_roll = (pertOutput.C_roll - nominalOutput.C_roll) / 0.05f;
pertOutput.Cy *= q * area * b / (2 * mass * u0);
pertOutput.Cn *= q * area * b * b / (2 * Iz * u0);
pertOutput.C_roll *= q * area * b * b / (2 * Ix * u0);
stabDerivOutput.stabDerivs[21] = pertOutput.Cy; //Yr
stabDerivOutput.stabDerivs[23] = pertOutput.Cn; //Nr
stabDerivOutput.stabDerivs[22] = pertOutput.C_roll; //Lr
return(stabDerivOutput);
}
