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flightgear/src/FDM/YASim/Wing.cpp
2008-09-29 08:00:20 +00:00

485 lines
12 KiB
C++

#include "Math.hpp"
#include "Surface.hpp"
#include "Wing.hpp"
namespace yasim {
Wing::Wing()
{
_mirror = false;
_base[0] = _base[1] = _base[2] = 0;
_length = 0;
_chord = 0;
_taper = 0;
_sweep = 0;
_dihedral = 0;
_stall = 0;
_stallWidth = 0;
_stallPeak = 0;
_twist = 0;
_camber = 0;
_incidence = 0;
_inducedDrag = 1;
_dragScale = 1;
_liftRatio = 1;
_flap0Start = 0;
_flap0End = 0;
_flap0Lift = 0;
_flap0Drag = 0;
_flap1Start = 0;
_flap1End = 0;
_flap1Lift = 0;
_flap1Drag = 0;
_spoilerStart = 0;
_spoilerEnd = 0;
_spoilerLift = 0;
_spoilerDrag = 0;
_slatStart = 0;
_slatEnd = 0;
_slatAoA = 0;
_slatDrag = 0;
}
Wing::~Wing()
{
int i;
for(i=0; i<_surfs.size(); i++) {
SurfRec* s = (SurfRec*)_surfs.get(i);
delete s->surface;
delete s;
}
}
int Wing::numSurfaces()
{
return _surfs.size();
}
Surface* Wing::getSurface(int n)
{
return ((SurfRec*)_surfs.get(n))->surface;
}
float Wing::getSurfaceWeight(int n)
{
return ((SurfRec*)_surfs.get(n))->weight;
}
void Wing::setMirror(bool mirror)
{
_mirror = mirror;
}
void Wing::setBase(float* base)
{
int i;
for(i=0; i<3; i++) _base[i] = base[i];
}
void Wing::setLength(float length)
{
_length = length;
}
void Wing::setChord(float chord)
{
_chord = chord;
}
void Wing::setTaper(float taper)
{
_taper = taper;
}
void Wing::setSweep(float sweep)
{
_sweep = sweep;
}
void Wing::setDihedral(float dihedral)
{
_dihedral = dihedral;
}
void Wing::setStall(float aoa)
{
_stall = aoa;
}
void Wing::setStallWidth(float angle)
{
_stallWidth = angle;
}
void Wing::setStallPeak(float fraction)
{
_stallPeak = fraction;
}
void Wing::setTwist(float angle)
{
_twist = angle;
}
void Wing::setCamber(float camber)
{
_camber = camber;
}
void Wing::setIncidence(float incidence)
{
_incidence = incidence;
int i;
for(i=0; i<_surfs.size(); i++)
((SurfRec*)_surfs.get(i))->surface->setIncidence(incidence);
}
void Wing::setFlap0(float start, float end, float lift, float drag)
{
_flap0Start = start;
_flap0End = end;
_flap0Lift = lift;
_flap0Drag = drag;
}
void Wing::setFlap1(float start, float end, float lift, float drag)
{
_flap1Start = start;
_flap1End = end;
_flap1Lift = lift;
_flap1Drag = drag;
}
void Wing::setSlat(float start, float end, float aoa, float drag)
{
_slatStart = start;
_slatEnd = end;
_slatAoA = aoa;
_slatDrag = drag;
}
void Wing::setSpoiler(float start, float end, float lift, float drag)
{
_spoilerStart = start;
_spoilerEnd = end;
_spoilerLift = lift;
_spoilerDrag = drag;
}
void Wing::setFlap0(float lval, float rval)
{
lval = Math::clamp(lval, -1, 1);
rval = Math::clamp(rval, -1, 1);
int i;
for(i=0; i<_flap0Surfs.size(); i++) {
((Surface*)_flap0Surfs.get(i))->setFlap(lval);
if(_mirror) ((Surface*)_flap0Surfs.get(++i))->setFlap(rval);
}
}
void Wing::setFlap0Effectiveness(float lval)
{
lval = Math::clamp(lval, 1, 10);
int i;
for(i=0; i<_flap0Surfs.size(); i++) {
((Surface*)_flap0Surfs.get(i))->setFlapEffectiveness(lval);
// if(_mirror) ((Surface*)_flap0Surfs.get(++i))->setFlapEffectiveness(rval);
}
}
void Wing::setFlap1(float lval, float rval)
{
lval = Math::clamp(lval, -1, 1);
rval = Math::clamp(rval, -1, 1);
int i;
for(i=0; i<_flap1Surfs.size(); i++) {
((Surface*)_flap1Surfs.get(i))->setFlap(lval);
if(_mirror) ((Surface*)_flap1Surfs.get(++i))->setFlap(rval);
}
}
void Wing::setFlap1Effectiveness(float lval)
{
lval = Math::clamp(lval, 1, 10);
int i;
for(i=0; i<_flap1Surfs.size(); i++) {
((Surface*)_flap1Surfs.get(i))->setFlapEffectiveness(lval);
// if(_mirror) ((Surface*)_flap1Surfs.get(++i))->setFlap(rval);
}
}
void Wing::setSpoiler(float lval, float rval)
{
lval = Math::clamp(lval, 0, 1);
rval = Math::clamp(rval, 0, 1);
int i;
for(i=0; i<_spoilerSurfs.size(); i++) {
((Surface*)_spoilerSurfs.get(i))->setSpoiler(lval);
if(_mirror) ((Surface*)_spoilerSurfs.get(++i))->setSpoiler(rval);
}
}
void Wing::setSlat(float val)
{
val = Math::clamp(val, 0, 1);
int i;
for(i=0; i<_slatSurfs.size(); i++)
((Surface*)_slatSurfs.get(i))->setSlat(val);
}
float Wing::getGroundEffect(float* posOut)
{
int i;
for(i=0; i<3; i++) posOut[i] = _base[i];
float span = _length * Math::cos(_sweep) * Math::cos(_dihedral);
span = 2*(span + Math::abs(_base[2]));
return span;
}
void Wing::getTip(float* tip)
{
tip[0] = -Math::tan(_sweep);
tip[1] = Math::cos(_dihedral);
tip[2] = Math::sin(_dihedral);
Math::unit3(tip, tip);
Math::mul3(_length, tip, tip);
Math::add3(_base, tip, tip);
}
bool Wing::isMirrored()
{
return _mirror;
}
void Wing::compile()
{
// Have we already been compiled?
if(_surfs.size() != 0) return;
// Assemble the start/end coordinates of all control surfaces
// and the wing itself into an array, sort them,
// and remove duplicates. This gives us the boundaries of our
// segments.
float bounds[10];
bounds[0] = _flap0Start; bounds[1] = _flap0End;
bounds[2] = _flap1Start; bounds[3] = _flap1End;
bounds[4] = _spoilerStart; bounds[5] = _spoilerEnd;
bounds[6] = _slatStart; bounds[7] = _slatEnd;
//and don't forget the root and the tip of the wing itself
bounds[8] = 0; bounds[9] = 1;
// Sort in increasing order
int i;
for(i=0; i<10; i++) {
int minIdx = i;
float minVal = bounds[i];
int j;
for(j=i+1; j<10; j++) {
if(bounds[j] < minVal) {
minIdx = j;
minVal = bounds[j];
}
}
float tmp = bounds[i];
bounds[i] = minVal; bounds[minIdx] = tmp;
}
// Uniqify
float last = bounds[0];
int nbounds = 1;
for(i=1; i<10; i++) {
if(bounds[i] != last)
bounds[nbounds++] = bounds[i];
last = bounds[i];
}
// Calculate a "nominal" segment length equal to an average chord,
// normalized to lie within 0-1 over the length of the wing.
float segLen = _chord * (0.5f*(_taper+1)) / _length;
// Generating a unit vector pointing out the left wing.
float left[3];
left[0] = -Math::tan(_sweep);
left[1] = Math::cos(_dihedral);
left[2] = Math::sin(_dihedral);
Math::unit3(left, left);
// Calculate coordinates for the root and tip of the wing
float root[3], tip[3];
Math::set3(_base, root);
Math::set3(left, tip);
Math::mul3(_length, tip, tip);
Math::add3(root, tip, tip);
// The wing's Y axis will be the "left" vector. The Z axis will
// be perpendicular to this and the local (!) X axis, because we
// want motion along the local X axis to be zero AoA (i.e. in the
// wing's XY plane) by definition. Then the local X coordinate is
// just Y cross Z.
float orient[9], rightOrient[9];
float *x = orient, *y = orient+3, *z = orient+6;
x[0] = 1; x[1] = 0; x[2] = 0;
Math::set3(left, y);
Math::cross3(x, y, z);
Math::unit3(z, z);
Math::cross3(y, z, x);
if(_mirror) {
// Derive the right side orientation matrix from this one.
int i;
for(i=0; i<9; i++) rightOrient[i] = orient[i];
// Negate all Y coordinates, this gets us a valid basis, but
// it's left handed! So...
for(i=1; i<9; i+=3) rightOrient[i] = -rightOrient[i];
// Change the direction of the Y axis to get back to a
// right-handed system.
for(i=3; i<6; i++) rightOrient[i] = -rightOrient[i];
}
// Now go through each boundary and make segments
for(i=0; i<(nbounds-1); i++) {
float start = bounds[i];
float end = bounds[i+1];
float mid = (start+end)/2;
bool flap0=0, flap1=0, slat=0, spoiler=0;
if(_flap0Start < mid && mid < _flap0End) flap0 = 1;
if(_flap1Start < mid && mid < _flap1End) flap1 = 1;
if(_slatStart < mid && mid < _slatEnd) slat = 1;
if(_spoilerStart < mid && mid < _spoilerEnd) spoiler = 1;
// FIXME: Should probably detect an error here if both flap0
// and flap1 are set. Right now flap1 overrides.
int nSegs = (int)Math::ceil((end-start)/segLen);
if (_twist != 0 && nSegs < 8) // more segments if twisted
nSegs = 8;
float segWid = _length * (end - start)/nSegs;
int j;
for(j=0; j<nSegs; j++) {
float frac = start + (j+0.5f) * (end-start)/nSegs;
float pos[3];
interp(root, tip, frac, pos);
float chord = _chord * (1 - (1-_taper)*frac);
Surface *s = newSurface(pos, orient, chord,
flap0, flap1, slat, spoiler);
SurfRec *sr = new SurfRec();
sr->surface = s;
sr->weight = chord * segWid;
s->setTotalDrag(sr->weight);
s->setTwist(_twist * frac);
_surfs.add(sr);
if(_mirror) {
pos[1] = -pos[1];
s = newSurface(pos, rightOrient, chord,
flap0, flap1, slat, spoiler);
sr = new SurfRec();
sr->surface = s;
sr->weight = chord * segWid;
s->setTotalDrag(sr->weight);
s->setTwist(_twist * frac);
_surfs.add(sr);
}
}
}
// Last of all, re-set the incidence in case setIncidence() was
// called before we were compiled.
setIncidence(_incidence);
}
float Wing::getDragScale()
{
return _dragScale;
}
void Wing::setDragScale(float scale)
{
_dragScale = scale;
int i;
for(i=0; i<_surfs.size(); i++) {
SurfRec* s = (SurfRec*)_surfs.get(i);
s->surface->setTotalDrag(scale * s->weight);
}
}
void Wing::setLiftRatio(float ratio)
{
_liftRatio = ratio;
int i;
for(i=0; i<_surfs.size(); i++)
((SurfRec*)_surfs.get(i))->surface->setZDrag(ratio);
}
float Wing::getLiftRatio()
{
return _liftRatio;
}
Surface* Wing::newSurface(float* pos, float* orient, float chord,
bool flap0, bool flap1, bool slat, bool spoiler)
{
Surface* s = new Surface();
s->setPosition(pos);
s->setOrientation(orient);
s->setChord(chord);
// Camber is expressed as a fraction of stall peak, so convert.
s->setBaseZDrag(_camber*_stallPeak);
// The "main" (i.e. normal) stall angle
float stallAoA = _stall - _stallWidth/4;
s->setStall(0, stallAoA);
s->setStallWidth(0, _stallWidth);
s->setStallPeak(0, _stallPeak);
// The negative AoA stall is the same if we're using an uncambered
// airfoil, otherwise a "little badder".
if(_camber > 0) {
s->setStall(1, stallAoA * 0.8f);
s->setStallWidth(1, _stallWidth * 0.5f);
} else {
s->setStall(1, stallAoA);
s->setStall(1, _stallWidth);
}
// The "reverse" stalls are unmeasurable junk. Just use 13deg and
// "sharp".
s->setStallPeak(1, 1);
int i;
for(i=2; i<4; i++) {
s->setStall(i, 0.2267f);
s->setStallWidth(i, 0.01);
}
if(flap0) s->setFlapParams(_flap0Lift, _flap0Drag);
if(flap1) s->setFlapParams(_flap1Lift, _flap1Drag);
if(slat) s->setSlatParams(_slatAoA, _slatDrag);
if(spoiler) s->setSpoilerParams(_spoilerLift, _spoilerDrag);
if(flap0) _flap0Surfs.add(s);
if(flap1) _flap1Surfs.add(s);
if(slat) _slatSurfs.add(s);
if(spoiler) _spoilerSurfs.add(s);
s->setInducedDrag(_inducedDrag);
return s;
}
void Wing::interp(float* v1, float* v2, float frac, float* out)
{
out[0] = v1[0] + frac*(v2[0]-v1[0]);
out[1] = v1[1] + frac*(v2[1]-v1[1]);
out[2] = v1[2] + frac*(v2[2]-v1[2]);
}
}; // namespace yasim