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flightgear/src/FDM/YASim/yasim-test.cpp

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C++
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#include <stdio.h>
#include <cstring>
#include <cstdlib>
#include <simgear/props/props.hxx>
#include <simgear/xml/easyxml.hxx>
#include <simgear/misc/sg_path.hxx>
#include "FGFDM.hpp"
#include "Atmosphere.hpp"
#include "RigidBody.hpp"
#include "Airplane.hpp"
using namespace yasim;
using std::string;
// Stubs. Not needed by a batch program, but required to link.
bool fgSetFloat (const char * name, float val) { return false; }
bool fgSetBool(char const * name, bool val) { return false; }
bool fgGetBool(char const * name, bool def) { return false; }
bool fgSetString(char const * name, char const * str) { return false; }
SGPropertyNode* fgGetNode (const char * path, bool create) { return 0; }
SGPropertyNode* fgGetNode (const char * path, int i, bool create) { return 0; }
float fgGetFloat (const char * name, float defaultValue) { return 0; }
double fgGetDouble (const char * name, double defaultValue = 0.0) { return 0; }
bool fgSetDouble (const char * name, double defaultValue = 0.0) { return 0; }
static const float RAD2DEG = 57.2957795131;
static const float DEG2RAD = 0.0174532925199;
/// knots 2 meters per second
static const float KTS2MPS = 0.514444444444;
enum Config
{
CONFIG_NONE,
CONFIG_APPROACH,
CONFIG_CRUISE,
};
// Generate a graph of lift, drag and L/D against AoA at the specified
// speed and altitude. The result is a space-separated file of
// numbers: "aoa lift drag LD" (aoa in degrees, lift and drag in
// G's). You can use this in gnuplot like so (assuming the output is
// in a file named "dat":
/*
plot "dat" using 1:2 with lines title 'lift', \
"dat" using 1:3 with lines title 'drag', \
"dat" using 1:4 with lines title 'LD'
*/
void yasim_graph(Airplane* a, const float alt, const float kts, int cfg = CONFIG_NONE)
{
Model* m = a->getModel();
State s;
m->setAirFromStandardAtmosphere(alt);
switch (cfg) {
case CONFIG_APPROACH:
a->loadApproachControls();
break;
case CONFIG_CRUISE:
a->loadCruiseControls();
break;
case CONFIG_NONE:
break;
}
//if we fake the properties we could also use FGFDM::getExternalInput()
m->getBody()->recalc();
float cl_max = 0, cd_min = 1e6, ld_max = 0;
int cl_max_deg = 0, cd_min_deg = 0, ld_max_deg = 0;
for(int deg=-15; deg<=90; deg++) {
float aoa = deg * DEG2RAD;
a->setupState(aoa, kts * KTS2MPS, 0 ,&s);
m->getBody()->reset();
m->initIteration();
m->calcForces(&s);
float acc[3];
m->getBody()->getAccel(acc);
Math::tmul33(s.orient, acc, acc);
float drag = acc[0] * (-1/9.8);
float lift = 1 + acc[2] * (1/9.8);
float ld = lift/drag;
if (cd_min > drag) {
cd_min = drag;
cd_min_deg = deg;
}
if (cl_max < lift) {
cl_max = lift;
cl_max_deg = deg;
}
if (ld_max < ld) {
ld_max= ld;
ld_max_deg = deg;
}
printf("%d %g %g %g\n", deg, lift, drag, ld);
}
printf("# cl_max %g at %d deg\n", cl_max, cl_max_deg);
printf("# cd_min %g at %d deg\n", cd_min, cd_min_deg);
printf("# ld_max %g at %d deg\n", ld_max, ld_max_deg);
}
void yasim_masses(Airplane* a)
{
RigidBody* body = a->getModel()->getBody();
int i, N = body->numMasses();
float pos[3];
float m, mass = 0;
printf("id posx posy posz mass\n");
for (i = 0; i < N; i++)
{
body->getMassPosition(i, pos);
m = body->getMass(i);
printf("%d %.3f %.3f %.3f %.3f\n", i, pos[0], pos[1], pos[2], m);
mass += m;
}
printf("Total mass: %g", mass);
}
void yasim_drag(Airplane* a, const float aoa, const float alt, int cfg = CONFIG_NONE)
{
fprintf(stderr,"yasim_drag");
Model* m = a->getModel();
State s;
m->setAirFromStandardAtmosphere(alt);
switch (cfg) {
case CONFIG_APPROACH:
a->loadApproachControls();
break;
case CONFIG_CRUISE:
a->loadCruiseControls();
break;
case CONFIG_NONE:
break;
}
m->getBody()->recalc();
float cd_min = 1e6;
int cd_min_kts = 0;
printf("#kts, drag\n");
for(int kts=15; kts<=150; kts++) {
a->setupState(aoa, kts * KTS2MPS, 0 ,&s);
m->getBody()->reset();
m->initIteration();
m->calcForces(&s);
float acc[3];
m->getBody()->getAccel(acc);
Math::tmul33(s.orient, acc, acc);
float drag = acc[0] * (-1/9.8);
if (cd_min > drag) {
cd_min = drag;
cd_min_kts = kts;
}
printf("%d %g\n", kts, drag);
}
printf("# cd_min %g at %d kts\n", cd_min, cd_min_kts);
}
int usage()
{
fprintf(stderr, "Usage: \n");
fprintf(stderr, " yasim <aircraft.xml> [-g [-a meters] [-s kts] [-approach | -cruise] ]\n");
fprintf(stderr, " yasim <aircraft.xml> [-d [-a meters] [-approach | -cruise] ]\n");
fprintf(stderr, " yasim <aircraft.xml> [-m]\n");
fprintf(stderr, " -g print lift/drag table: aoa, lift, drag, lift/drag \n");
fprintf(stderr, " -d print drag over TAS: kts, drag\n");
fprintf(stderr, " -a set altitude in meters!\n");
fprintf(stderr, " -s set speed in knots\n");
fprintf(stderr, " -m print mass distribution table: id, x, y, z, mass \n");
return 1;
}
int main(int argc, char** argv)
{
FGFDM* fdm = new FGFDM();
Airplane* a = fdm->getAirplane();
if(argc < 2) return usage();
// Read
try {
string file = argv[1];
readXML(SGPath(file), *fdm);
}
catch (const sg_exception &e) {
printf("XML parse error: %s (%s)\n", e.getFormattedMessage().c_str(), e.getOrigin());
}
// ... and run
a->compile();
if(a->getFailureMsg())
printf("SOLUTION FAILURE: %s\n", a->getFailureMsg());
if(!a->getFailureMsg() && argc > 2 ) {
if(strcmp(argv[2], "-g") == 0) {
float alt = 5000, kts = 100;
int cfg = CONFIG_NONE;
for(int i=3; i<argc; i++) {
if (std::strcmp(argv[i], "-a") == 0) {
if (i+1 < argc) alt = std::atof(argv[++i]);
}
else if(std::strcmp(argv[i], "-s") == 0) {
if(i+1 < argc) kts = std::atof(argv[++i]);
}
else if(std::strcmp(argv[i], "-approach") == 0) cfg = CONFIG_APPROACH;
else if(std::strcmp(argv[i], "-cruise") == 0) cfg = CONFIG_CRUISE;
else return usage();
}
yasim_graph(a, alt, kts, cfg);
}
else if(strcmp(argv[2], "-d") == 0) {
float alt = 2000, aoa = a->getCruiseAoA();
int cfg = CONFIG_NONE;
for(int i=3; i<argc; i++) {
if (std::strcmp(argv[i], "-a") == 0) {
if (i+1 < argc) alt = std::atof(argv[++i]);
}
else if(std::strcmp(argv[i], "-approach") == 0) cfg = CONFIG_APPROACH;
else if(std::strcmp(argv[i], "-cruise") == 0) cfg = CONFIG_CRUISE;
else return usage();
}
yasim_drag(a, aoa, alt, cfg);
}
else if(strcmp(argv[2], "-m") == 0) {
yasim_masses(a);
}
}
else {
printf("==========================\n");
printf("= YASim solution results =\n");
printf("==========================\n");
float aoa = a->getCruiseAoA() * RAD2DEG;
float tail = -1 * a->getTailIncidence() * RAD2DEG;
float drag = 1000 * a->getDragCoefficient();
float cg[3];
a->getModel()->getBody()->getCG(cg);
a->getModel()->getBody()->recalc();
float SI_inertia[9];
a->getModel()->getBody()->getInertiaMatrix(SI_inertia);
float MAC = a->getWing()->getMAC();
float MACx = a->getWing()->getMACx();
float MACy = a->getWing()->getMACy();
printf(" Iterations: %d\n", a->getSolutionIterations());
printf(" Drag Coefficient: %f\n", drag);
printf(" Lift Ratio: %f\n", a->getLiftRatio());
printf(" Cruise AoA: %f deg\n", aoa);
printf(" Tail Incidence: %f deg\n", tail);
printf("Approach Elevator: %f\n\n", a->getApproachElevator());
printf(" CG: x:%.3f, y:%.3f, z:%.3f\n", cg[0], cg[1], cg[2]);
printf(" Wing MAC (*1): x:%.2f, y:%.2f, length:%.1f \n", MACx, MACy, MAC);
printf(" CG-x rel. MAC: %.3f\n", a->getCGMAC());
printf(" CG-x desired: %.3f < %.3f < %.3f \n", a->getCGSoftLimitXMin(), cg[0], a->getCGSoftLimitXMax());
printf("\nInertia tensor [kg*m^2], origo at CG:\n\n");
printf(" %7.3f, %7.3f, %7.3f\n", SI_inertia[0], SI_inertia[1], SI_inertia[2]);
printf(" %7.3f, %7.3f, %7.3f\n", SI_inertia[3], SI_inertia[4], SI_inertia[5]);
printf(" %7.3f, %7.3f, %7.3f\n", SI_inertia[6], SI_inertia[7], SI_inertia[8]);
printf("\n(*1) MAC calculation works on <wing> only! Numbers will be wrong for segmented wings, e.g. <wing>+<mstab>.\n");
}
delete fdm;
return 0;
}
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